test(ai): expand unit and functional coverage for /ai feature

Unit tests (tests/unittests/test_ai_client.c): +50 cases on top of the
existing 50 — total 100. Covers:
  - chat response parser (ai_parse_response): OpenAI content + Perplexity
    text formats, escape decoding, empty/null/missing inputs, format-string
    safety, multiline content
  - error envelope parser (ai_parse_error_message): standard envelope,
    nested escapes, missing fields, null/empty
  - extended JSON escape: \b, \f, \r, all-specials, UTF-8 pass-through
  - provider autocomplete cycling with >=2 matches and wrap-around
  - session edge cases: NULL args, 100-message order preservation,
    set_model(NULL), ref/unref(NULL)
  - provider edge cases: get/remove with NULL, double-remove, survival
    via session ref after ai_remove_provider
  - settings: multi-key independence, missing key, cross-provider
    isolation
  - model parsing edges: data not array, empty data, "id" outside data,
    multiple models
  - prefs round-trip: set token -> shutdown -> init -> token reloaded
    from disk (uses load_preferences fixture)

Functional tests:
  - Tier A (test_ai.c): 15 cases for the /ai command surface that don't
    need HTTP. Covers /ai help, providers list, set provider/token,
    start with/without key/unknown provider, clear, remove, default
    provider/model, switch without window, bad subcommand.
  - Tier B (test_ai_http.c + ai_http_stub.{c,h,py}): 5 cases that
    exercise the libcurl path against a local Python HTTP stub. The
    stub serves canned bodies in five modes (ok, openai, 401, 500,
    models) so each chat/models/error path is hit end-to-end without
    network.

Infrastructure:
  - TEST_GROUPS bumped to 5 in proftest.c; AI tests live in their own
    Group 5 because mixing them with stabber-driven tests in Group 4
    poisoned stbbr_stop() teardown.
  - PROF_FUNC_TEST_AI macro in functionaltests.c registers AI tests
    with ai_init_test() which wraps init_prof_test with a prof_connect()
    so stabber sees a graceful disconnect at teardown.
  - dist_check_DATA ships ai_http_stub.py with the source tarball.

Source-level changes to enable testing:
  - src/ai/ai_client.{c,h}: dropped 'static' from _parse_ai_response
    (renamed ai_parse_response) and _parse_error_response (renamed
    ai_parse_error_message); declared under a "Parsing helpers (exposed
    for testing)" section. Same approach as ai_parse_models_from_json.

Results in Docker (cproof-debian image):
  - 595/595 unit tests pass
  - 20/20 AI functional tests pass (Group 5)

Makefile.am

@@ -37,6 +37,7 @@ core_sources = \
 	src/ui/window_list.c src/ui/window_list.h \
 	src/ui/rosterwin.c src/ui/occupantswin.c \
 	src/ui/buffer.c src/ui/buffer.h \
+	src/ui/aiwin.c \
 	src/ui/chatwin.c \
 	src/ui/mucwin.c \
 	src/ui/privwin.c \
@@ -78,7 +79,8 @@ core_sources = \
 	src/plugins/themes.c src/plugins/themes.h \
 	src/plugins/settings.c src/plugins/settings.h \
 	src/plugins/disco.c src/plugins/disco.h \
-	src/ui/tray.h src/ui/tray.c
+	src/ui/tray.h src/ui/tray.c \
+	src/ai/ai_client.h src/ai/ai_client.c
 
 unittest_sources = \
 	src/xmpp/contact.c src/xmpp/contact.h src/common.c \
@@ -89,6 +91,7 @@ unittest_sources = \
 	src/xmpp/chat_state.h src/xmpp/chat_state.c \
 	src/xmpp/roster_list.c src/xmpp/roster_list.h \
 	src/xmpp/xmpp.h src/xmpp/form.c \
+	src/ai/ai_client.h src/ai/ai_client.c \
 	src/ui/ui.h \
 	src/otr/otr.h \
 	src/pgp/gpg.h \
@@ -138,6 +141,7 @@ unittest_sources = \
 	tests/unittests/xmpp/stub_message.c \
 	tests/unittests/ui/stub_ui.c tests/unittests/ui/stub_ui.h \
 	tests/unittests/ui/stub_vcardwin.c \
+	tests/unittests/ui/stub_ai.c \
 	tests/unittests/log/stub_log.c \
 	tests/unittests/chatlog/stub_chatlog.c \
 	tests/unittests/database/stub_database.c \
@@ -174,6 +178,7 @@ unittest_sources = \
 	tests/unittests/test_callbacks.c tests/unittests/test_callbacks.h \
 	tests/unittests/test_plugins_disco.c tests/unittests/test_plugins_disco.h \
 	tests/unittests/test_forced_encryption.c tests/unittests/test_forced_encryption.h \
+	tests/unittests/test_ai_client.c tests/unittests/test_ai_client.h \
 	tests/unittests/test_database_export.c tests/unittests/test_database_export.h \
 	tests/unittests/test_database_stress.c tests/unittests/test_database_stress.h \
 	tests/unittests/unittests.c
@@ -198,8 +203,13 @@ functionaltest_sources = \
 	tests/functionaltests/test_autoping.c tests/functionaltests/test_autoping.h \
 	tests/functionaltests/test_disco.c tests/functionaltests/test_disco.h \
 	tests/functionaltests/test_export_import.c tests/functionaltests/test_export_import.h \
+	tests/functionaltests/test_ai.c tests/functionaltests/test_ai.h \
+	tests/functionaltests/ai_http_stub.c tests/functionaltests/ai_http_stub.h \
+	tests/functionaltests/test_ai_http.c tests/functionaltests/test_ai_http.h \
 	tests/functionaltests/functionaltests.c
 
+dist_check_DATA = tests/functionaltests/ai_http_stub.py
+
 main_source = src/main.c
 
 python_sources = \

src/ai/ai_client.h

@@ -0,0 +1,275 @@
+#ifndef AI_CLIENT_H
+#define AI_CLIENT_H
+
+#include <glib.h>
+
+/**
+ * @brief AI message structure for conversation history.
+ */
+typedef struct ai_message_t
+{
+    gchar* role;    /* "user" or "assistant" */
+    gchar* content; /* Message content */
+} AIMessage;
+
+/**
+ * @brief AI provider configuration.
+ */
+typedef struct ai_provider_t
+{
+    gchar* name;           /* Provider name (e.g., "openai", "perplexity") */
+    gchar* api_url;        /* API endpoint URL */
+    gchar* org_id;         /* Optional organization ID */
+    gchar* project_id;     /* Optional project ID (for some providers) */
+    gchar* default_model;  /* Default model for this provider */
+    GHashTable* settings;  /* Extensible per-provider settings (e.g., tools=enabled, search=disabled) */
+    GList* models;         /* Cached models (gchar*) */
+    gboolean models_fresh; /* Whether models cache is current */
+    gint32 ref_count;      /* Reference count (atomic) */
+} AIProvider;
+
+/**
+ * @brief AI chat session structure.
+ */
+typedef struct ai_session_t
+{
+    gchar* provider_name; /* Provider name */
+    AIProvider* provider; /* Provider configuration */
+    gchar* model;         /* Model identifier (e.g., "gpt-4", "sonar") */
+    gchar* api_key;       /* API key for this session */
+    GList* history;       /* Conversation history (GList of AIMessage*) */
+    gint32 ref_count;     /* Reference count (atomic) */
+} AISession;
+
+/* ========================================================================
+ * Provider Management
+ * ======================================================================== */
+
+/**
+ * Initialize the AI client and load default providers.
+ */
+void ai_client_init(void);
+
+/**
+ * Shutdown the AI client and free resources.
+ */
+void ai_client_shutdown(void);
+
+/**
+ * Get a provider by name.
+ * @param name The provider name (e.g., "openai", "perplexity")
+ * @return AIProvider*, or NULL if not found
+ */
+AIProvider* ai_get_provider(const gchar* name);
+
+/**
+ * Add or update a provider configuration.
+ * @param name The provider name
+ * @param api_url The API endpoint URL
+ * @param org_id Optional organization ID (can be NULL)
+ * @return New AIProvider* (caller must unref when done)
+ */
+AIProvider* ai_add_provider(const gchar* name, const gchar* api_url, const gchar* org_id);
+
+/**
+ * Remove a provider by name.
+ * @param name The provider name
+ * @return TRUE if provider was removed, FALSE if not found
+ */
+gboolean ai_remove_provider(const gchar* name);
+
+/**
+ * Decrement the reference count of a provider.
+ * @param provider The provider to unreference
+ */
+void ai_provider_unref(AIProvider* provider);
+
+/**
+ * List all configured providers.
+ * @return GList of AIProvider* (caller must not free the list or providers,
+ *         and must not unref the returned providers)
+ */
+GList* ai_list_providers(void);
+
+/**
+ * Find a provider name for autocomplete.
+ * @param search_str The search string
+ * @param previous Whether to go to previous match
+ * @param context Unused
+ * @return Provider name, or NULL if not found
+ */
+gchar* ai_providers_find(const char* const search_str, gboolean previous, void* context);
+
+/**
+ * Find a model name for autocomplete.
+ * @param search_str The search string
+ * @param previous Whether to go to previous match
+ * @param context ProfAiWin* for the current session
+ * @return Model name, or NULL if not found
+ */
+gchar* ai_models_find(const char* const search_str, gboolean previous, void* context);
+
+/**
+ * Get the API key for a provider.
+ * @param provider_name The provider name
+ * @return The API key, or NULL if not set (caller must free)
+ */
+gchar* ai_get_provider_key(const gchar* provider_name);
+
+/**
+ * Set the API key for a provider.
+ * @param provider_name The provider name
+ * @param api_key The API key to set
+ */
+void ai_set_provider_key(const gchar* provider_name, const gchar* api_key);
+
+/**
+ * Set the default model for a provider.
+ * @param provider_name The provider name
+ * @param model The default model name
+ */
+void ai_set_provider_default_model(const gchar* provider_name, const gchar* model);
+
+/**
+ * Get the default model for a provider.
+ * @param provider_name The provider name
+ * @return The default model name (caller must not free), or NULL if not set
+ */
+const gchar* ai_get_provider_default_model(const gchar* provider_name);
+
+/**
+ * Set a custom setting for a provider.
+ * @param provider_name The provider name
+ * @param setting The setting key (e.g., "tools", "search")
+ * @param value The setting value
+ */
+void ai_set_provider_setting(const gchar* provider_name, const gchar* setting, const gchar* value);
+
+/**
+ * Get a custom setting for a provider.
+ * @param provider_name The provider name
+ * @param setting The setting key
+ * @return The setting value (caller must free), or NULL if not set
+ */
+gchar* ai_get_provider_setting(const gchar* provider_name, const gchar* setting);
+
+/**
+ * Fetch available models from a provider's API.
+ * @param provider_name The provider name
+ * @param user_data User data (ProfAiWin* for UI display)
+ * @return TRUE if the request was successfully queued, FALSE otherwise
+ */
+gboolean ai_fetch_models(const gchar* provider_name, gpointer user_data);
+
+/**
+ * Check if models cache is fresh for a provider.
+ * @param provider_name The provider name
+ * @return TRUE if models are fresh, FALSE otherwise
+ */
+gboolean ai_models_are_fresh(const gchar* provider_name);
+
+/* ========================================================================
+ * Parsing helpers (exposed for testing)
+ * ======================================================================== */
+
+/**
+ * Parse model IDs from an OpenAI-compatible API response.
+ * Expected format: {"object":"list","data":[{"id":"model1",...},...]}
+ * @param provider The provider to add models to
+ * @param json The JSON response from the API
+ */
+void ai_parse_models_from_json(AIProvider* provider, const gchar* json);
+
+/**
+ * Extract assistant content from an LLM response body. Tries Perplexity
+ * /v1/responses "text" first, falls back to OpenAI "content". Decodes
+ * the \" and \n escape sequences only.
+ * @param response_json The JSON body from the provider
+ * @return Newly allocated content string, or NULL if not found (caller frees)
+ */
+gchar* ai_parse_response(const gchar* response_json);
+
+/**
+ * Extract human-readable error message from an API error envelope.
+ * Expected format: {"error":{"message":"...","type":"...","code":...}}
+ * Decodes \" \n \\ \t escapes.
+ * @param error_json The JSON body of the error response
+ * @return Newly allocated error message, or NULL if not parseable (caller frees)
+ */
+gchar* ai_parse_error_message(const gchar* error_json);
+
+/* ========================================================================
+ * Session Management
+ * ======================================================================== */
+
+/**
+ * Create a new AI session with the specified provider and model.
+ * @param provider_name The provider name (e.g., "openai")
+ * @param model The model identifier (e.g., "gpt-4")
+ * @return New AISession*, or NULL on failure
+ */
+AISession* ai_session_create(const gchar* provider_name, const gchar* model);
+
+/**
+ * Increment the reference count of an AI session.
+ * @param session The session to reference
+ * @return The same session pointer
+ */
+AISession* ai_session_ref(AISession* session);
+
+/**
+ * Decrement the reference count and free the session when it reaches zero.
+ * @param session The session to unreference
+ */
+void ai_session_unref(AISession* session);
+
+/**
+ * Add a message to the session history.
+ * @param session The session
+ * @param role The message role ("user" or "assistant")
+ * @param content The message content
+ */
+void ai_session_add_message(AISession* session, const gchar* role, const gchar* content);
+
+/**
+ * Clear the conversation history.
+ * @param session The session
+ */
+void ai_session_clear_history(AISession* session);
+
+/**
+ * Get the current model for a session.
+ * @param session The session
+ * @return The model name (caller must not free)
+ */
+const gchar* ai_session_get_model(AISession* session);
+
+/**
+ * Set the model for a session.
+ * @param session The session
+ * @param model The model name
+ */
+void ai_session_set_model(AISession* session, const gchar* model);
+
+/* ========================================================================
+ * Request Handling
+ * ======================================================================== */
+
+/**
+ * Send a prompt to the AI provider asynchronously.
+ * @param session The AI session containing provider and model
+ * @param prompt The prompt to send
+ * @param user_data User data (ProfAiWin* for UI display)
+ * @return TRUE if the request was successfully queued, FALSE otherwise
+ */
+gboolean ai_send_prompt(AISession* session, const gchar* prompt,
+                        gpointer user_data);
+
+/**
+ * Escape a string for JSON embedding.
+ * @param str The string to escape
+ * @return Newly allocated escaped string (caller must free)
+ */
+gchar* ai_json_escape(const gchar* str);
+
+#endif /* AI_CLIENT_H */

src/command/cmd_ac.c

@@ -66,8 +66,11 @@
 #include "omemo/omemo.h"
 #endif
 
+#include "ai/ai_client.h"
+
 static char* _sub_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _notify_autocomplete(ProfWin* window, const char* const input, gboolean previous);
+static char* _ai_model_autocomplete(ProfWin* window, const char* const input, gboolean previous, const char* prefix);
 static char* _theme_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _autoaway_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _autoconnect_autocomplete(ProfWin* window, const char* const input, gboolean previous);
@@ -137,6 +140,7 @@ static char* _strophe_autocomplete(ProfWin* window, const char* const input, gbo
 static char* _adhoc_cmd_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _vcard_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _force_encryption_autocomplete(ProfWin* window, const char* const input, gboolean previous);
+static char* _ai_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 
 static char* _script_autocomplete_func(const char* const prefix, gboolean previous, void* context);
 
@@ -280,11 +284,16 @@ static Autocomplete history_switch_ac;
 static Autocomplete color_ac;
 static Autocomplete correction_ac;
 static Autocomplete avatar_ac;
+static Autocomplete ai_subcommands_ac;
+static Autocomplete ai_set_subcommands_ac;
+static Autocomplete ai_set_custom_subcommands_ac;
+static Autocomplete ai_remove_subcommands_ac;
 static Autocomplete url_ac;
 static Autocomplete executable_ac;
 static Autocomplete executable_param_ac;
 static Autocomplete intype_ac;
 static Autocomplete mood_ac;
+static Autocomplete ai_models_ac;
 static Autocomplete mood_type_ac;
 static Autocomplete strophe_ac;
 static Autocomplete strophe_sm_ac;
@@ -456,7 +465,11 @@ static Autocomplete* all_acs[] = {
     &vcard_togglable_param_ac,
     &vcard_address_type_ac,
     &force_encryption_ac,
-    &force_encryption_policy_ac
+    &force_encryption_policy_ac,
+    &ai_subcommands_ac,
+    &ai_set_subcommands_ac,
+    &ai_set_custom_subcommands_ac,
+    &ai_remove_subcommands_ac
 };
 
 static GHashTable* ac_funcs = NULL;
@@ -1169,6 +1182,27 @@ cmd_ac_init(void)
     autocomplete_add(correction_ac, "off");
     autocomplete_add(correction_ac, "char");
 
+    autocomplete_add_unsorted(ai_subcommands_ac, "set", FALSE);
+    autocomplete_add_unsorted(ai_subcommands_ac, "remove", FALSE);
+    autocomplete_add_unsorted(ai_subcommands_ac, "start", FALSE);
+    autocomplete_add_unsorted(ai_subcommands_ac, "clear", FALSE);
+    autocomplete_add_unsorted(ai_subcommands_ac, "providers", FALSE);
+    autocomplete_add_unsorted(ai_subcommands_ac, "switch", FALSE);
+    autocomplete_add_unsorted(ai_subcommands_ac, "models", FALSE);
+
+    autocomplete_add_unsorted(ai_set_subcommands_ac, "provider", FALSE);
+    autocomplete_add_unsorted(ai_set_subcommands_ac, "token", FALSE);
+    autocomplete_add_unsorted(ai_set_subcommands_ac, "default-provider", FALSE);
+    autocomplete_add_unsorted(ai_set_subcommands_ac, "default-model", FALSE);
+    autocomplete_add_unsorted(ai_set_subcommands_ac, "custom", FALSE);
+
+    autocomplete_add_unsorted(ai_set_custom_subcommands_ac, "tools", FALSE);
+    autocomplete_add_unsorted(ai_set_custom_subcommands_ac, "search", FALSE);
+    autocomplete_add_unsorted(ai_set_custom_subcommands_ac, "memory", FALSE);
+    autocomplete_add_unsorted(ai_set_custom_subcommands_ac, "plugins", FALSE);
+
+    autocomplete_add_unsorted(ai_remove_subcommands_ac, "provider", FALSE);
+
     autocomplete_add(avatar_ac, "set");
     autocomplete_add(avatar_ac, "disable");
     autocomplete_add(avatar_ac, "get");
@@ -1444,6 +1478,7 @@ cmd_ac_init(void)
     g_hash_table_insert(ac_funcs, "/wins", _wins_autocomplete);
     g_hash_table_insert(ac_funcs, "/wintitle", _wintitle_autocomplete);
     g_hash_table_insert(ac_funcs, "/force-encryption", _force_encryption_autocomplete);
+    g_hash_table_insert(ac_funcs, "/ai", _ai_autocomplete);
 }
 
 void
@@ -4450,4 +4485,167 @@ _force_encryption_autocomplete(ProfWin* window, const char* const input, gboolea
 
     result = autocomplete_param_with_ac(input, "/force-encryption", force_encryption_ac, TRUE, previous);
     return result;
-}
+}
+
+static char*
+_ai_autocomplete(ProfWin* window, const char* const input, gboolean previous)
+{
+    char* result = NULL;
+
+    /* Parse once for reuse - /ai <subcommand> [<arg1>] [<arg2>] */
+    gboolean parse_result = FALSE;
+    auto_gcharv gchar** args = parse_args(input, 1, 4, &parse_result);
+    gboolean space_at_end = g_str_has_suffix(input, " ");
+    int num_args = g_strv_length(args);
+
+    /* Top-level /ai <subcommand> autocomplete (e.g., /ai s<tab> -> /ai set) */
+    result = autocomplete_param_with_func(input, "/ai set provider", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai set token <provider> <token> - autocomplete provider names
+    result = autocomplete_param_with_func(input, "/ai set token", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai set default-provider <provider> - autocomplete provider names
+    result = autocomplete_param_with_func(input, "/ai set default-provider", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai set default-model <provider> <model> - autocomplete provider names
+    result = autocomplete_param_with_func(input, "/ai set default-model", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai set custom <provider> <setting> <value> - autocomplete provider names
+    result = autocomplete_param_with_func(input, "/ai set custom", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai set custom <provider> <setting> - autocomplete settings
+    /* args[0]="set", args[1]="custom", args[2]=provider (if typed), args[3]=setting (if typed) */
+    if (num_args == 3 && g_strcmp0(args[1], "custom") == 0) {
+        /* /ai set custom <provider> - check if provider is valid */
+        if (ai_get_provider(args[2])) {
+            /* Valid provider, try settings autocomplete */
+            result = autocomplete_param_with_ac(input, "/ai set custom ", ai_set_custom_subcommands_ac, TRUE, previous);
+            if (result) {
+                return result;
+            }
+        }
+    }
+    // /ai set <subcommand> - autocomplete subcommands
+    result = autocomplete_param_with_ac(input, "/ai set", ai_set_subcommands_ac, TRUE, previous);
+    if (result) {
+        return result;
+    }
+
+    // /ai remove provider <name> - autocomplete provider names
+    result = autocomplete_param_with_func(input, "/ai remove provider", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    result = autocomplete_param_with_ac(input, "/ai remove", ai_remove_subcommands_ac, TRUE, previous);
+    if (result) {
+        return result;
+    }
+
+    // /ai start [<provider>] [<model>] - use shared parse_args
+    if (parse_result && args && args[0] != NULL && g_strcmp0(args[0], "start") == 0) {
+        /* args[0]="start", args[1]=provider (if typed), args[2]=model (if typed) */
+        if (num_args == 1 || (num_args == 2 && !space_at_end)) {
+            result = autocomplete_param_with_func(input, "/ai start", ai_providers_find, previous, NULL);
+        } else {
+            /* /ai start <provider> <model> - model autocomplete */
+            result = _ai_model_autocomplete(window, input, previous, "/ai start ");
+        }
+        if (result) {
+            return result;
+        }
+    }
+
+    // /ai switch <provider> <model> - autocomplete model names for specified provider
+    result = _ai_model_autocomplete(window, input, previous, "/ai switch");
+    if (result) {
+        return result;
+    }
+
+    result = autocomplete_param_with_func(input, "/ai switch", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai switch <model> - autocomplete model names from current session's provider
+    ProfAiWin* aiwin = (window && window->type == WIN_AI) ? (ProfAiWin*)window : wins_get_ai();
+    result = autocomplete_param_with_func(input, "/ai switch", ai_models_find, previous, aiwin);
+    if (result) {
+        return result;
+    }
+
+    // /ai models <provider> - autocomplete provider names
+    result = autocomplete_param_with_func(input, "/ai models", ai_providers_find, previous, NULL);
+    if (result) {
+        return result;
+    }
+
+    // /ai clear - no autocomplete
+    // /ai providers - no autocomplete
+
+    result = autocomplete_param_with_ac(input, "/ai", ai_subcommands_ac, FALSE, previous);
+
+    return result;
+}
+
+/**
+ * Autocomplete model names for /ai <cmd> <provider> <model> patterns.
+ * Extracts provider from input and provides model completions from that provider's cached models.
+ * Uses static ai_models_ac to preserve cycling state (last_found) across calls.
+ */
+static char*
+_ai_model_autocomplete(ProfWin* window, const char* const input, gboolean previous, const char* cmd_prefix)
+{
+    if (!g_str_has_prefix(input, cmd_prefix)) {
+        return NULL;
+    }
+
+    /* Extract provider name from input (after cmd_prefix) */
+    auto_gchar gchar* rest = g_strdup(input + strlen(cmd_prefix));
+    char* space = strchr(rest, ' ');
+    if (space) {
+        *space = '\0';
+    }
+
+    /* Look up the provider by name and get its models */
+    AIProvider* prov = ai_get_provider(rest);
+    if (!prov || !prov->models) {
+        return NULL;
+    }
+
+    if (!ai_models_ac) {
+        ai_models_ac = autocomplete_new();
+    }
+    /* Convert GList* to char** for autocomplete_update */
+    int model_count = g_list_length(prov->models);
+    char** model_array = g_new0(char*, model_count + 1);
+    GList* curr = prov->models;
+    int i = 0;
+    while (curr) {
+        model_array[i++] = curr->data;
+        curr = g_list_next(curr);
+    }
+
+    autocomplete_update(ai_models_ac, model_array);
+    g_free(model_array);
+
+    auto_gchar gchar* full_prefix = g_strdup_printf("%s%s", cmd_prefix, rest);
+
+    char* result = autocomplete_param_with_ac(input, full_prefix, ai_models_ac, TRUE, previous);
+    return result;
+}

src/command/cmd_defs.c

@@ -2787,6 +2787,71 @@ static const struct cmd_t command_defs[] = {
               "/force-encryption policy block")
     },
 
+    { CMD_PREAMBLE("/ai",
+                   parse_args, 0, 5, NULL)
+      CMD_SUBFUNCS(
+              { "set", cmd_ai_set },
+              { "remove", cmd_ai_remove },
+              { "start", cmd_ai_start },
+              { "clear", cmd_ai_clear },
+              { "providers", cmd_ai_providers },
+              { "switch", cmd_ai_switch },
+              { "models", cmd_ai_models })
+      CMD_MAINFUNC(cmd_ai)
+      CMD_TAGS(
+              CMD_TAG_CHAT)
+      CMD_SYN(
+              "/ai",
+              "/ai set provider <name> <url>",
+              "/ai set token <provider> <token>",
+              "/ai set default-provider <provider>",
+              "/ai set default-model <provider> <model>",
+              "/ai set custom <provider> <setting> <value>",
+              "/ai remove provider <name>",
+              "/ai providers",
+              "/ai start [<provider>] [<model>]",
+              "/ai switch <provider> [<model>]",
+              "/ai switch <model>",
+              "/ai models <provider>",
+              "/ai clear")
+      CMD_DESC(
+              "Interact with AI models via OpenAI-compatible APIs. "
+              "Supports multiple providers (openai, perplexity, custom). "
+              "Each provider has its own API key, endpoint, default model, and settings. "
+              "Chat history is maintained per session and not persisted locally.")
+      CMD_ARGS(
+              { "", "Display current AI settings and configured providers" },
+              { "set provider <name> <url>", "Add or update a provider with custom API endpoint" },
+              { "set token <provider> <token>", "Set API token for a provider (e.g., openai, perplexity)" },
+              { "set default-provider <provider>", "Set global default provider for /ai start" },
+              { "set default-model <provider> <model>", "Set default model for a provider" },
+              { "set custom <provider> <setting> <value>", "Set provider-level setting (e.g., tools, search)" },
+              { "remove provider <name>", "Remove a custom provider" },
+              { "providers", "List configured providers with full details" },
+              { "start [<provider>] [<model>]", "Start new AI chat (space-separated, uses defaults if omitted)" },
+              { "switch <provider> [<model>]", "Switch to different provider (and optionally model)" },
+              { "switch <model>", "Change model in current session (keeps provider)" },
+              { "models <provider>", "Fetch and display available models for provider" },
+              { "clear", "Clear current chat history" })
+      CMD_EXAMPLES(
+              "/ai",
+              "/ai set token openai sk-xxx",
+              "/ai set token perplexity pplx-xxx",
+              "/ai set provider custom https://my-api.com/v1/chat/completions",
+              "/ai set default-provider perplexity",
+              "/ai set default-model perplexity sonar",
+              "/ai set custom perplexity tools enabled",
+              "/ai remove provider custom",
+              "/ai start",
+              "/ai start perplexity",
+              "/ai start perplexity sonar",
+              "/ai start openai gpt-4o",
+              "/ai switch gpt-4o",
+              "/ai switch openai gpt-5.4-nano",
+              "/ai models perplexity",
+              "/ai clear")
+    },
+
     // NEXT-COMMAND (search helper)
 };
 

src/command/cmd_funcs.c

@@ -81,7 +81,6 @@
 #include "tools/bookmark_ignore.h"
 #include "tools/editor.h"
 #include "plugins/plugins.h"
-#include "ui/inputwin.h"
 #include "ui/ui.h"
 #include "ui/window_list.h"
 #include "xmpp/avatar.h"
@@ -117,6 +116,8 @@
 #include "tools/clipboard.h"
 #endif
 
+#include "ai/ai_client.h"
+
 #ifdef HAVE_PYTHON
 #include "plugins/python_plugins.h"
 #endif
@@ -8466,7 +8467,7 @@ _cmd_execute_default(ProfWin* window, const char* inp)
     }
 
     // handle non commands in non chat or plugin windows
-    if (window->type != WIN_CHAT && window->type != WIN_MUC && window->type != WIN_PRIVATE && window->type != WIN_PLUGIN && window->type != WIN_XML) {
+    if (window->type != WIN_CHAT && window->type != WIN_MUC && window->type != WIN_PRIVATE && window->type != WIN_PLUGIN && window->type != WIN_XML && window->type != WIN_AI) {
         cons_show("Unknown command: %s", inp);
         cons_alert(NULL);
         return TRUE;
@@ -8512,6 +8513,12 @@ _cmd_execute_default(ProfWin* window, const char* inp)
         connection_send_stanza(inp);
         break;
     }
+    case WIN_AI:
+    {
+        ProfAiWin* aiwin = (ProfAiWin*)window;
+        cl_ev_send_ai_msg(aiwin, inp, NULL);
+        break;
+    }
     default:
         break;
     }
@@ -10780,6 +10787,500 @@ cmd_vcard_save(ProfWin* window, const char* const command, gchar** args)
     return TRUE;
 }
 
+gboolean
+cmd_ai(ProfWin* window, const char* const command, gchar** args)
+{
+    if (args[0] == NULL) {
+        // Display current AI settings
+        cons_show("AI Chat - OpenAI-compatible API client");
+        cons_show("");
+
+        // List configured providers with full details
+        GList* providers = ai_list_providers();
+        cons_show("Configured providers:");
+        for (GList* curr = providers; curr; curr = g_list_next(curr)) {
+            AIProvider* provider = curr->data;
+            auto_gchar gchar* key = ai_get_provider_key(provider->name);
+            const gchar* default_model = ai_get_provider_default_model(provider->name);
+            cons_show("  %s", provider->name);
+            cons_show("    URL: %s", provider->api_url);
+            cons_show("    Key: %s", key ? "configured" : "NOT configured");
+            if (default_model) {
+                cons_show("    Default model: %s", default_model);
+            }
+            if (provider->models && g_list_length(provider->models) > 0) {
+                cons_show("    Cached models: %d", g_list_length(provider->models));
+            }
+            cons_show("");
+        }
+        g_list_free(providers);
+
+        cons_show("Use '/ai start' to begin a chat (uses default provider/model).");
+        cons_show("Use '/ai models <provider>' to fetch available models.");
+        cons_show("Available models: https://models.litellm.ai/");
+        return TRUE;
+    }
+
+    cons_bad_cmd_usage(command);
+    return TRUE;
+}
+
+gboolean
+cmd_ai_set(ProfWin* window, const char* const command, gchar** args)
+{
+    if (args[1] == NULL) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    if (g_strcmp0(args[1], "provider") == 0) {
+        // /ai set provider <name> <url>
+        if (g_strv_length(args) < 4) {
+            cons_bad_cmd_usage(command);
+            return TRUE;
+        }
+        if (ai_add_provider(args[2], args[3], NULL)) {
+            cons_show("Provider '%s' configured with URL: %s", args[2], args[3]);
+        } else {
+            cons_show_error("Failed to configure provider '%s'.", args[2]);
+        }
+        cons_show("");
+        return TRUE;
+    } else if (g_strcmp0(args[1], "token") == 0) {
+        // /ai set token <provider> <token>
+        if (g_strv_length(args) < 4) {
+            cons_bad_cmd_usage(command);
+            return TRUE;
+        }
+        ai_set_provider_key(args[2], args[3]);
+        cons_show("API token set for provider: %s", args[2]);
+        cons_show("");
+        return TRUE;
+    } else if (g_strcmp0(args[1], "default-model") == 0) {
+        // /ai set default-model <provider> <model>
+        if (g_strv_length(args) < 4) {
+            cons_bad_cmd_usage(command);
+            return TRUE;
+        }
+        ai_set_provider_default_model(args[2], args[3]);
+        cons_show("Default model for provider '%s' set to: %s", args[2], args[3]);
+        cons_show("");
+        return TRUE;
+    } else if (g_strcmp0(args[1], "custom") == 0) {
+        // /ai set custom <provider> <setting> <value>
+        if (g_strv_length(args) < 5) {
+            cons_bad_cmd_usage(command);
+            return TRUE;
+        }
+        ai_set_provider_setting(args[2], args[3], args[4]);
+        cons_show("Setting '%s' for provider '%s' set to: %s", args[3], args[2], args[4]);
+        cons_show("");
+        return TRUE;
+    } else if (g_strcmp0(args[1], "default-provider") == 0) {
+        // /ai set default-provider <provider>
+        if (g_strv_length(args) < 3) {
+            cons_bad_cmd_usage(command);
+            return TRUE;
+        }
+        const gchar* provider_name = args[2];
+        AIProvider* provider = ai_get_provider(provider_name);
+        if (!provider) {
+            cons_show_error("Provider '%s' not found. Use '/ai set provider %s <url>' to add it.",
+                            provider_name, provider_name);
+            return TRUE;
+        }
+        prefs_set_string(PREF_AI_PROVIDER, provider_name);
+        cons_show("Default provider set to: %s", provider_name);
+        cons_show("");
+        return TRUE;
+    }
+
+    cons_bad_cmd_usage(command);
+    return TRUE;
+}
+
+gboolean
+cmd_ai_remove(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai remove provider <name>
+    if (g_strcmp0(args[1], "provider") != 0) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    if (g_strv_length(args) < 3) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    if (ai_remove_provider(args[2])) {
+        cons_show("Provider '%s' removed.", args[2]);
+    } else {
+        cons_show("Provider '%s' not found.", args[2]);
+    }
+    cons_show("");
+    return TRUE;
+}
+
+gboolean
+cmd_ai_start(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai start [<provider>] [<model>]
+    // Space-separated, no slash syntax
+    const gchar* provider_name = NULL;
+    const gchar* model = NULL;
+
+    if (g_strv_length(args) >= 2) {
+        provider_name = args[1];
+    }
+    if (g_strv_length(args) >= 3) {
+        model = args[2];
+    }
+
+    // Resolve defaults
+    auto_gchar gchar* owned_provider_name = NULL;
+    if (!provider_name) {
+        // Use default provider from preferences
+        auto_gchar gchar* default_provider = prefs_get_string(PREF_AI_PROVIDER);
+        if (default_provider && strlen(default_provider) > 0) {
+            provider_name = default_provider;
+        }
+    }
+    if (!provider_name) {
+        provider_name = "openai"; // Fallback
+    }
+
+    AIProvider* provider = ai_get_provider(provider_name);
+    if (!provider) {
+        cons_show_error("Provider '%s' not found. Use '/ai set provider %s <url>' to add it.",
+                        provider_name, provider_name);
+        return TRUE;
+    }
+
+    // Get model: explicit > provider default > hardcoded fallback
+    if (!model) {
+        model = ai_get_provider_default_model(provider_name);
+    }
+    if (!model) {
+        model = "gpt-4o"; // Fallback
+    }
+
+    // Check for API key
+    gchar* api_key = ai_get_provider_key(provider_name);
+    if (!api_key || strlen(api_key) == 0) {
+        cons_show_error("No API key set for provider '%s'. Use '/ai set token %s <key>' first.",
+                        provider_name, provider_name);
+        g_free(api_key);
+        return TRUE;
+    }
+    g_free(api_key);
+
+    // Create new AI session
+    AISession* session = ai_session_create(provider_name, model);
+    if (!session) {
+        log_error("[AI-CMD] Failed to create AI session");
+        cons_show_error("Failed to create AI session for %s/%s.", provider_name, model);
+        return TRUE;
+    }
+    log_debug("[AI-CMD] AI session created successfully");
+
+    // Create AI chat window
+    log_debug("[AI-CMD] Calling wins_new_ai()...");
+    ProfWin* ai_win = wins_new_ai(session);
+    if (!ai_win) {
+        log_error("[AI-CMD] wins_new_ai() returned NULL");
+        cons_show_error("Failed to create AI chat window.");
+        ai_session_unref(session);
+        return TRUE;
+    }
+    log_debug("[AI-CMD] wins_new_ai() returned successfully, window type: %d", ai_win->type);
+
+    // Add welcome message to the AI window
+    log_debug("[AI-CMD] Adding welcome messages...");
+    win_println(ai_win, THEME_DEFAULT, "-", "AI Chat: %s/%s", provider_name, model);
+    win_println(ai_win, THEME_DEFAULT, "-", "Type your message and press Enter to start a conversation.");
+    log_debug("[AI-CMD] Welcome messages added");
+
+    // Focus the new window
+    log_debug("[AI-CMD] Calling ui_focus_win()...");
+    ui_focus_win(ai_win);
+    log_debug("[AI-CMD] ui_focus_win() returned");
+
+    cons_show("Started AI chat: %s/%s", provider_name, model);
+    cons_show("");
+    log_debug("[AI-CMD] AI start command completed");
+
+    return TRUE;
+}
+
+gboolean
+cmd_ai_model(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai model <model>
+    if (args[1] == NULL) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    const gchar* model = args[1];
+
+    // Get current AI window
+    ProfAiWin* aiwin = (window && window->type == WIN_AI) ? (ProfAiWin*)window : wins_get_ai();
+    if (!aiwin) {
+        cons_show("No active AI chat window. Use '/ai start' first.");
+        return TRUE;
+    }
+
+    assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+
+    if (!aiwin->session) {
+        cons_show("No active session in this chat window.");
+        return TRUE;
+    }
+
+    ai_session_set_model(aiwin->session, model);
+    cons_show("Session model changed to: %s", model);
+    cons_show("");
+    return TRUE;
+}
+
+gboolean
+cmd_ai_switch(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai switch <provider> [<model>] - Change provider and optionally model
+    // /ai switch <model> - Change model only (keeps current provider)
+    // Modifies the existing session's provider and model instead of recreating it
+    if (g_strv_length(args) < 2) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    // Get current AI window
+    ProfAiWin* aiwin = (window && window->type == WIN_AI) ? (ProfAiWin*)window : wins_get_ai();
+    if (!aiwin) {
+        cons_show("No active AI chat window. Use '/ai start' first.");
+        return TRUE;
+    }
+
+    assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+
+    if (!aiwin->session) {
+        cons_show("No active session in this chat window.");
+        return TRUE;
+    }
+
+    const gchar* arg1 = args[1];
+    const gchar* arg2 = (g_strv_length(args) >= 3) ? args[2] : NULL;
+
+    const gchar* provider_name;
+    const gchar* model;
+    gboolean changed_provider = FALSE;
+
+    // Check if arg1 is a known provider
+    AIProvider* provider = ai_get_provider(arg1);
+    if (provider) {
+        // arg1 is a provider name
+        provider_name = arg1;
+        changed_provider = TRUE;
+
+        // Get model: arg2 > provider default > error
+        if (arg2) {
+            model = arg2;
+        } else {
+            model = ai_get_provider_default_model(provider_name);
+        }
+        if (!model) {
+            cons_show_error("No model specified and no default model set for provider '%s'.", provider_name);
+            cons_show("Use '/ai set default-model %s <model>' or '/ai switch %s <model>'.", provider_name, provider_name);
+            return TRUE;
+        }
+    } else {
+        // arg1 is a model name, keep current provider
+        provider_name = aiwin->session->provider_name;
+        model = arg1;
+    }
+
+    // Check for API key
+    auto_gchar gchar* api_key = ai_get_provider_key(provider_name);
+    if (!api_key || strlen(api_key) == 0) {
+        cons_show_error("No API key set for provider '%s'. Use '/ai set token %s <key>' first.",
+                        provider_name, provider_name);
+        return TRUE;
+    }
+
+    // Update the existing session's provider and model
+    if (changed_provider) {
+        AIProvider* new_provider = ai_get_provider(provider_name);
+        g_free(aiwin->session->provider_name);
+        aiwin->session->provider_name = g_strdup(provider_name);
+        ai_provider_unref(aiwin->session->provider);
+        aiwin->session->provider = new_provider;
+        aiwin->session->provider->ref_count++;
+    }
+    g_free(aiwin->session->model);
+    aiwin->session->model = g_strdup(model);
+    g_free(aiwin->session->api_key);
+    aiwin->session->api_key = g_strdup(api_key);
+
+    // Update window title
+    win_println((ProfWin*)aiwin, THEME_DEFAULT, "-", "AI Chat: %s/%s", provider_name, model);
+
+    cons_show("Switched to %s/%s", provider_name, model);
+    cons_show("");
+
+    return TRUE;
+}
+
+gboolean
+cmd_ai_models(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai models <provider> [--cached]
+    // Default: fetch fresh models from API
+    // --cached: display cached models (if available)
+    if (args[1] == NULL) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    const gchar* provider_name = args[1];
+    gboolean use_cached = (g_strv_length(args) >= 3) && (g_strcmp0(args[2], "--cached") == 0);
+
+    AIProvider* provider = ai_get_provider(provider_name);
+    if (!provider) {
+        cons_show_error("Provider '%s' not found.", provider_name);
+        return TRUE;
+    }
+
+    if (use_cached) {
+        // Display cached models (if available)
+        if (!provider->models) {
+            cons_show("No cached models for provider '%s'. Use '/ai models %s' to fetch from API.", provider_name, provider_name);
+            return TRUE;
+        }
+        cons_show("Cached models for provider '%s':", provider_name);
+        GList* curr = provider->models;
+        while (curr) {
+            cons_show("  %s", (gchar*)curr->data);
+            curr = g_list_next(curr);
+        }
+        cons_show("");
+        cons_show("Use '/ai models %s' to fetch fresh models from the API.", provider_name);
+    } else {
+        // Default: fetch fresh models from API
+        ProfAiWin* aiwin = (window && window->type == WIN_AI) ? (ProfAiWin*)window : wins_get_ai();
+        ai_fetch_models(provider_name, aiwin);
+    }
+
+    return TRUE;
+}
+
+gboolean
+cmd_ai_clear(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai clear
+    ProfAiWin* aiwin = (window && window->type == WIN_AI) ? (ProfAiWin*)window : wins_get_ai();
+
+    if (aiwin) {
+        assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+        if (aiwin->session) {
+            ai_session_clear_history(aiwin->session);
+        }
+        cons_show("Chat history cleared.");
+    } else {
+        cons_show("No active AI chat window to clear.");
+    }
+    cons_show("");
+    return TRUE;
+}
+
+gboolean
+cmd_ai_correct(ProfWin* window, const char* const command, gchar** args)
+{
+    // /ai correct <message>
+    // Join all arguments from args[1] onwards to support multi-word prompts
+    auto_gchar gchar* prompt = g_strjoinv(" ", &args[1]);
+    if (prompt == NULL || strlen(prompt) == 0) {
+        cons_bad_cmd_usage(command);
+        return TRUE;
+    }
+
+    // Get current AI window
+    ProfAiWin* aiwin = wins_get_ai();
+    if (!aiwin) {
+        cons_show("No active AI chat window. Use '/ai start <provider>/<model>' first.");
+        return TRUE;
+    }
+
+    assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+
+    if (!aiwin->session) {
+        cons_show("No active session in this chat window.");
+        return TRUE;
+    }
+
+    // Get the last user message and replace it
+    GList* history = aiwin->session->history;
+    GList* last_user_msg = NULL;
+    for (GList* curr = history; curr; curr = g_list_next(curr)) {
+        AIMessage* msg = curr->data;
+        if (g_strcmp0(msg->role, "user") == 0) {
+            last_user_msg = curr;
+        }
+    }
+
+    if (!last_user_msg) {
+        cons_show("No user messages in this chat to correct.");
+        return TRUE;
+    }
+
+    // Replace the last user message
+    AIMessage* msg = last_user_msg->data;
+    g_free(msg->content);
+    msg->content = g_strdup(prompt);
+
+    // Resend the prompt
+    cons_show("Correcting message...");
+    ai_send_prompt(aiwin->session, prompt, aiwin);
+
+    return TRUE;
+}
+
+gboolean
+cmd_ai_providers(ProfWin* window, const char* const command, gchar** args)
+{
+    if (args[1] == NULL || g_strcmp0(args[1], "list") != 0) {
+        // List all available providers
+        cons_show("Available AI providers:");
+        cons_show("");
+        cons_show("  openai      - OpenAI API (https://api.openai.com)");
+        cons_show("  perplexity  - Perplexity API (https://api.perplexity.ai)");
+        cons_show("");
+        cons_show("Add custom providers with: /ai set provider <name> <url>");
+        return TRUE;
+    }
+
+    // List configured providers with key status
+    cons_show("Configured providers:");
+    cons_show("");
+
+    GList* providers = ai_list_providers();
+    for (GList* curr = providers; curr; curr = g_list_next(curr)) {
+        AIProvider* provider = curr->data;
+        gchar* key = ai_get_provider_key(provider->name);
+        cons_show("  %s", provider->name);
+        cons_show("    URL: %s", provider->api_url);
+        cons_show("    Key: %s", key ? "configured" : "NOT configured");
+        if (provider->org_id && strlen(provider->org_id) > 0) {
+            cons_show("    Org: %s", provider->org_id);
+        }
+        cons_show("");
+        g_free(key);
+    }
+    g_list_free(providers);
+
+    return TRUE;
+}
+
 gboolean
 cmd_force_encryption(ProfWin* window, const char* const command, gchar** args)
 {

src/command/cmd_funcs.h

@@ -166,6 +166,14 @@ gboolean cmd_console(ProfWin* window, const char* const command, gchar** args);
 gboolean cmd_command_list(ProfWin* window, const char* const command, gchar** args);
 gboolean cmd_command_exec(ProfWin* window, const char* const command, gchar** args);
 gboolean cmd_change_password(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_set(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_remove(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_start(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_clear(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_providers(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_switch(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_ai_models(ProfWin* window, const char* const command, gchar** args);
 
 gboolean cmd_plugins(ProfWin* window, const char* const command, gchar** args);
 gboolean cmd_plugins_sourcepath(ProfWin* window, const char* const command, gchar** args);

src/config/preferences.c

@@ -66,6 +66,7 @@
 #define PREF_GROUP_MUC           "muc"
 #define PREF_GROUP_PLUGINS       "plugins"
 #define PREF_GROUP_EXECUTABLES   "executables"
+#define PREF_GROUP_AI            "ai"
 
 #define INPBLOCK_DEFAULT 1000
 
@@ -1706,6 +1707,162 @@ _save_prefs(void)
     save_keyfile(&prefs_prof_keyfile);
 }
 
+/* ========================================================================
+ * AI Token Management
+ * ======================================================================== */
+
+gboolean
+prefs_ai_set_token(const char* const provider, const char* const token)
+{
+    if (!provider)
+        return FALSE;
+
+    if (!prefs)
+        return FALSE;
+
+    if (token) {
+        g_key_file_set_string(prefs, PREF_GROUP_AI, provider, token);
+        _save_prefs();
+        return TRUE;
+    } else {
+        return prefs_ai_remove_token(provider);
+    }
+}
+
+gboolean
+prefs_ai_remove_token(const char* const provider)
+{
+    if (!provider)
+        return FALSE;
+
+    if (!prefs)
+        return FALSE;
+
+    if (!g_key_file_has_key(prefs, PREF_GROUP_AI, provider, NULL)) {
+        return FALSE;
+    }
+
+    g_key_file_remove_key(prefs, PREF_GROUP_AI, provider, NULL);
+    _save_prefs();
+    return TRUE;
+}
+
+char*
+prefs_ai_get_token(const char* const provider)
+{
+    if (!provider || !prefs)
+        return NULL;
+
+    return g_key_file_get_string(prefs, PREF_GROUP_AI, provider, NULL);
+}
+
+GList*
+prefs_ai_list_tokens(void)
+{
+    if (!prefs || !g_key_file_has_group(prefs, PREF_GROUP_AI)) {
+        return NULL;
+    }
+
+    GList* result = NULL;
+    gsize len;
+    auto_gcharv gchar** keys = g_key_file_get_keys(prefs, PREF_GROUP_AI, &len, NULL);
+
+    for (gsize i = 0; i < len; i++) {
+        char* name = keys[i];
+        auto_gchar gchar* value = g_key_file_get_string(prefs, PREF_GROUP_AI, name, NULL);
+        if (value) {
+            result = g_list_append(result, g_strdup(name));
+        }
+    }
+
+    return result;
+}
+
+void
+prefs_free_ai_tokens(GList* tokens)
+{
+    if (tokens) {
+        g_list_free_full(tokens, g_free);
+    }
+}
+
+gboolean
+prefs_ai_set_models(const char* const provider, const gchar* const* models, gint count)
+{
+    if (!provider || count <= 0)
+        return FALSE;
+
+    if (!prefs)
+        return FALSE;
+
+    /* Build semicolon-separated model list */
+    GString* model_str = g_string_new("");
+    for (int i = 0; i < count; i++) {
+        if (i > 0) {
+            g_string_append_c(model_str, ';');
+        }
+        g_string_append(model_str, models[i]);
+    }
+
+    g_key_file_set_string(prefs, PREF_GROUP_AI, g_strconcat(provider, "_models", NULL), model_str->str);
+    g_string_free(model_str, TRUE);
+    _save_prefs();
+    return TRUE;
+}
+
+gboolean
+prefs_ai_remove_models(const char* const provider)
+{
+    if (!provider)
+        return FALSE;
+
+    if (!prefs)
+        return FALSE;
+
+    auto_gchar gchar* key = g_strconcat(provider, "_models", NULL);
+    if (!g_key_file_has_key(prefs, PREF_GROUP_AI, key, NULL)) {
+        return FALSE;
+    }
+
+    g_key_file_remove_key(prefs, PREF_GROUP_AI, key, NULL);
+    _save_prefs();
+    return TRUE;
+}
+
+GList*
+prefs_ai_get_models(const char* const provider)
+{
+    if (!provider || !prefs)
+        return NULL;
+
+    auto_gchar gchar* key = g_strconcat(provider, "_models", NULL);
+    if (!g_key_file_has_key(prefs, PREF_GROUP_AI, key, NULL)) {
+        return NULL;
+    }
+
+    auto_gchar gchar* model_str = g_key_file_get_string(prefs, PREF_GROUP_AI, key, NULL);
+    if (!model_str || strlen(model_str) == 0) {
+        return NULL;
+    }
+
+    GList* result = NULL;
+    gchar** models = g_strsplit(model_str, ";", -1);
+    for (int i = 0; models[i] != NULL; i++) {
+        result = g_list_append(result, g_strdup(models[i]));
+    }
+    g_strfreev(models);
+
+    return result;
+}
+
+void
+prefs_free_ai_models(GList* models)
+{
+    if (models) {
+        g_list_free_full(models, g_free);
+    }
+}
+
 // get the preference group for a specific preference
 // for example the PREF_BEEP setting ("beep" in .profrc, see _get_key) belongs
 // to the [ui] section.
@@ -1865,6 +2022,9 @@ _get_group(preference_t pref)
         return PREF_GROUP_OMEMO;
     case PREF_OX_LOG:
         return PREF_GROUP_OX;
+    case PREF_AI_PROVIDER:
+    case PREF_AI_API_KEY:
+        return PREF_GROUP_AI;
     default:
         return NULL;
     }
@@ -2142,6 +2302,10 @@ _get_key(preference_t pref)
         return "stamp.incoming";
     case PREF_OX_LOG:
         return "log";
+    case PREF_AI_PROVIDER:
+        return "provider";
+    case PREF_AI_API_KEY:
+        return "api_key";
     case PREF_MOOD:
         return "mood";
     case PREF_VCARD_PHOTO_CMD:
@@ -2319,6 +2483,10 @@ _get_default_string(preference_t pref)
         return "on";
     case PREF_FORCE_ENCRYPTION_MODE:
         return "resend-to-confirm";
+    case PREF_AI_PROVIDER:
+        return "openai";
+    case PREF_AI_API_KEY:
+        return "";
     default:
         return NULL;
     }

src/config/preferences.h

@@ -183,6 +183,9 @@ typedef enum {
     PREF_OX_LOG,
     PREF_MOOD,
     PREF_STROPHE_VERBOSITY,
+    PREF_AI_PROVIDER,
+    PREF_AI_API_KEY,
+    PREF_AI_DEFAULT_MODEL,
     PREF_STROPHE_SM_ENABLED,
     PREF_STROPHE_SM_RESEND,
     PREF_VCARD_PHOTO_CMD,
@@ -356,4 +359,17 @@ gboolean prefs_get_room_notify(const char* const roomjid);
 gboolean prefs_get_room_notify_mention(const char* const roomjid);
 gboolean prefs_get_room_notify_trigger(const char* const roomjid);
 
+/* AI token management */
+gboolean prefs_ai_set_token(const char* const provider, const char* const token);
+gboolean prefs_ai_remove_token(const char* const provider);
+char* prefs_ai_get_token(const char* const provider);
+GList* prefs_ai_list_tokens(void);
+void prefs_free_ai_tokens(GList* tokens);
+
+/* AI model cache management */
+gboolean prefs_ai_set_models(const char* const provider, const gchar* const* models, gint count);
+gboolean prefs_ai_remove_models(const char* const provider);
+GList* prefs_ai_get_models(const char* const provider);
+void prefs_free_ai_models(GList* models);
+
 #endif

src/event/client_events.c

@@ -37,8 +37,10 @@
 #include "config.h"
 
 #include <stdlib.h>
+#include <assert.h>
 #include <glib.h>
 
+#include "ai/ai_client.h"
 #include "log.h"
 #include "chatlog.h"
 #include "database.h"
@@ -47,7 +49,7 @@
 #include "event/common.h"
 #include "plugins/plugins.h"
 #include "ui/inputwin.h"
-#include "ui/window_list.h"
+#include "ui/window.h"
 #include "xmpp/chat_session.h"
 #include "xmpp/session.h"
 #include "xmpp/xmpp.h"
@@ -284,3 +286,30 @@ allow_unencrypted_message(ProfChatWin* chatwin, const char* const msg)
     win_println((ProfWin*)chatwin, THEME_ERROR, "-", "Message not sent: invalid encryption mode (%s). Use '/force-encryption policy resend-to-confirm'.", force_enc_mode);
     return FALSE;
 }
+
+void
+cl_ev_send_ai_msg(ProfAiWin* aiwin, const char* const message, const char* const id)
+{
+    if (!aiwin || !message) {
+        return;
+    }
+
+    assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+
+    if (!aiwin->session) {
+        log_error("[AI] AI session not initialized");
+        return;
+    }
+
+    /* Reset paged flag before printing user message.
+     * If the user scrolled up to view history, paged=1 would suppress
+     * the message in _win_printf(). Reset it here so the message displays. */
+    aiwin->window.layout->paged = 0;
+    aiwin->window.layout->unread_msg = 0;
+
+    // Display user message in AI window.
+    win_print_outgoing(&aiwin->window, ">>", id, NULL, message);
+
+    // Send to AI provider.
+    ai_send_prompt(aiwin->session, message, aiwin);
+}

src/event/client_events.h

@@ -51,6 +51,7 @@ void cl_ev_send_msg(ProfChatWin* chatwin, const char* const msg, const char* con
 void cl_ev_send_muc_msg_corrected(ProfMucWin* mucwin, const char* const msg, const char* const oob_url, gboolean correct_last_msg);
 void cl_ev_send_muc_msg(ProfMucWin* mucwin, const char* const msg, const char* const oob_url);
 void cl_ev_send_priv_msg(ProfPrivateWin* privwin, const char* const msg, const char* const oob_url);
+void cl_ev_send_ai_msg(ProfAiWin* aiwin, const char* const message, const char* const id);
 
 // Checks if an unencrypted message can be sent based on encryption preferences.
 // Returns TRUE if allowed, FALSE if blocked.

src/profanity.c

@@ -69,6 +69,7 @@
 #include "xmpp/xmpp.h"
 #include "xmpp/muc.h"
 #include "xmpp/chat_session.h"
+#include "ai/ai_client.h"
 #include "xmpp/chat_state.h"
 #include "xmpp/contact.h"
 #include "xmpp/roster_list.h"
@@ -249,6 +250,7 @@ _init(char* log_level, char* config_file, char* log_file, char* theme_name)
     }
     session_init();
     cmd_init();
+    ai_client_init();
     log_info("Initialising contact list");
     muc_init();
     tlscerts_init();

src/ui/aiwin.c

@@ -0,0 +1,61 @@
+/*
+ * aiwin.c - AI Chat Window Management
+ *
+ * Provides functions for managing the AI chat window (ProfAiWin) in the
+ * profanity client. This includes retrieving window strings for identification,
+ * displaying AI/LLM responses in the chat view, and handling error messages
+ * from AI interactions.
+ *
+ * Key functions:
+ *   aiwin_get_string()       - Returns a descriptive string for the window
+ *   aiwin_display_response() - Displays an AI/LLM response and appends it
+ *                              to the conversation history
+ *   aiwin_display_error()    - Displays an error message from AI operations
+ *
+ * vim: expandtab:ts=4:sts=4:sw=4
+ */
+
+#include "config.h"
+
+#include <assert.h>
+
+#include "ai/ai_client.h"
+#include "log.h"
+#include "ui/ui.h"
+#include "ui/win_types.h"
+
+char*
+aiwin_get_string(ProfAiWin* win)
+{
+    assert(win->memcheck == PROFAIWIN_MEMCHECK);
+    return g_strdup_printf("AI Chat (%s: %s)", win->session->provider_name, win->session->model);
+}
+
+void
+aiwin_display_response(ProfAiWin* win, const char* response)
+{
+    log_debug("[AI-WIN] aiwin_display_response ENTER: win=%p, response='%s'", (void*)win, response);
+    assert(win->memcheck == PROFAIWIN_MEMCHECK);
+
+    if (!response) {
+        log_error("[AI-WIN] FAIL: null response");
+        return;
+    }
+
+    // Display AI response
+    win_println(&win->window, THEME_DEFAULT, "<< LLM:", "%s", response);
+    log_debug("[AI-WIN] Displayed AI response");
+}
+
+void
+aiwin_display_error(ProfAiWin* win, const char* error_msg)
+{
+    log_debug("[AI-WIN] aiwin_display_error ENTER: win=%p, error='%s'", (void*)win, error_msg);
+    assert(win->memcheck == PROFAIWIN_MEMCHECK);
+
+    const char* msg = error_msg ? error_msg : "Unknown error";
+    win_println(&win->window, THEME_ERROR, "[ERROR]", "%s", msg);
+
+    // Also show error in console so user sees it regardless of active window
+    cons_show_error("AI Error: %s", msg);
+}

src/ui/ui.h

@@ -386,6 +386,8 @@ ProfWin* win_create_config(const char* const title, DataForm* form, ProfConfWinC
 ProfWin* win_create_private(const char* const fulljid);
 ProfWin* win_create_plugin(const char* const plugin_name, const char* const tag);
 ProfWin* win_create_vcard(vCard* vcard);
+ProfWin* win_create_ai(AISession* session);
+ProfWin* wins_new_ai(AISession* session);
 void win_update_virtual(ProfWin* window);
 void win_free(ProfWin* window);
 gboolean win_notify_remind(ProfWin* window);
@@ -445,4 +447,9 @@ void notify_invite(const char* const from, const char* const room, const char* c
 void notify(const char* const message, int timeout, const char* const category);
 void notify_subscription(const char* const from);
 
+/* AI window */
+char* aiwin_get_string(ProfAiWin* win);
+void aiwin_display_response(ProfAiWin* win, const char* response);
+void aiwin_display_error(ProfAiWin* win, const char* error_msg);
+
 #endif

src/ui/win_types.h

@@ -62,6 +62,7 @@
 #define PROFXMLWIN_MEMCHECK     87333463
 #define PROFPLUGINWIN_MEMCHECK  43434777
 #define PROFVCARDWIN_MEMCHECK   68947523
+#define PROFAIWIN_MEMCHECK      91827364
 
 typedef enum {
     FIELD_HIDDEN,
@@ -144,7 +145,8 @@ typedef enum {
     WIN_PRIVATE,
     WIN_XML,
     WIN_PLUGIN,
-    WIN_VCARD
+    WIN_VCARD,
+    WIN_AI
 } win_type_t;
 
 typedef enum {
@@ -258,4 +260,16 @@ typedef struct prof_vcard_win_t
     unsigned long memcheck;
 } ProfVcardWin;
 
+/* Forward declaration */
+typedef struct ai_session_t AISession;
+
+typedef struct prof_ai_win_t
+{
+    ProfWin window;
+    ProfBuff message_buffer;
+    GString* conversation_history;
+    AISession* session;
+    unsigned long memcheck;
+} ProfAiWin;
+
 #endif

src/ui/window.c

@@ -36,6 +36,7 @@
 
 #include "config.h"
 #include "database.h"
+#include "ui/win_types.h"
 #include "ui/window_list.h"
 
 #include <stdlib.h>
@@ -62,6 +63,7 @@
 #include "ui/screen.h"
 #include "xmpp/xmpp.h"
 #include "xmpp/roster_list.h"
+#include "ai/ai_client.h"
 
 static const char* LOADING_MESSAGE = "Loading older messages…";
 static const char* CONS_WIN_TITLE = "CProof. Type /help for help information.";
@@ -329,6 +331,22 @@ win_create_vcard(vCard* vcard)
     return &new_win->window;
 }
 
+ProfWin*
+win_create_ai(AISession* session)
+{
+    ProfAiWin* new_win = g_new0(ProfAiWin, 1);
+    new_win->window.type = WIN_AI;
+    new_win->window.scroll_state = WIN_SCROLL_INNER;
+    new_win->window.layout = _win_create_simple_layout();
+
+    new_win->message_buffer = buffer_create();
+    new_win->conversation_history = g_string_new("");
+    new_win->session = session ? ai_session_ref(session) : NULL;
+    new_win->memcheck = PROFAIWIN_MEMCHECK;
+
+    return &new_win->window;
+}
+
 gchar*
 win_get_title(ProfWin* window)
 {
@@ -407,6 +425,13 @@ win_get_title(ProfWin* window)
 
         return g_string_free(title, FALSE);
     }
+    case WIN_AI:
+    {
+        const ProfAiWin* aiwin = (ProfAiWin*)window;
+        assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+
+        return g_strdup_printf("AI Assistant (%s: %s)", aiwin->session->provider_name, aiwin->session->model);
+    }
     }
     assert(FALSE);
 }
@@ -454,6 +479,10 @@ win_get_tab_identifier(ProfWin* window)
     {
         return strdup("vcard");
     }
+    case WIN_AI:
+    {
+        return strdup("ai");
+    }
     }
     assert(FALSE);
 }
@@ -536,6 +565,12 @@ win_to_string(ProfWin* window)
         ProfVcardWin* vcardwin = (ProfVcardWin*)window;
         return vcardwin_get_string(vcardwin);
     }
+    case WIN_AI:
+    {
+        ProfAiWin* aiwin = (ProfAiWin*)window;
+        assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+        return aiwin_get_string(aiwin);
+    }
     }
     assert(FALSE);
 }
@@ -662,6 +697,17 @@ win_free(ProfWin* window)
         free(pluginwin->plugin_name);
         break;
     }
+    case WIN_AI:
+    {
+        ProfAiWin* aiwin = (ProfAiWin*)window;
+        assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+        buffer_free(aiwin->message_buffer);
+        g_string_free(aiwin->conversation_history, TRUE);
+        if (aiwin->session) {
+            ai_session_unref(aiwin->session);
+        }
+        break;
+    }
     default:
         break;
     }

src/ui/window_list.c

@@ -44,9 +44,11 @@
 
 #include "common.h"
 #include "config/preferences.h"
+#include "log.h"
 #include "config/theme.h"
 #include "plugins/plugins.h"
 #include "ui/ui.h"
+#include "ui/window.h"
 #include "ui/window_list.h"
 #include "xmpp/xmpp.h"
 #include "xmpp/roster_list.h"
@@ -374,6 +376,8 @@ wins_set_current_by_num(int i)
                 status_bar_active(1, conswin->type, "console");
             }
         }
+    } else {
+        log_error("Window not found for index %d", i);
     }
 }
 
@@ -714,6 +718,20 @@ wins_new_vcard(vCard* vcard)
     return newwin;
 }
 
+ProfWin*
+wins_new_ai(AISession* session)
+{
+    int result = _wins_get_next_available_num(keys);
+    ProfWin* newwin = win_create_ai(session);
+    if (!newwin) {
+        return NULL;
+    }
+    _wins_htable_insert(windows, GINT_TO_POINTER(result), newwin);
+    autocomplete_add(wins_ac, "ai");
+    autocomplete_add(wins_close_ac, "ai");
+    return newwin;
+}
+
 gboolean
 wins_do_notify_remind(void)
 {
@@ -841,7 +859,7 @@ wins_get_prune_wins(void)
 
     while (curr) {
         ProfWin* window = curr->data;
-        if (win_unread(window) == 0 && window->type != WIN_MUC && window->type != WIN_CONFIG && window->type != WIN_XML && window->type != WIN_CONSOLE) {
+        if (win_unread(window) == 0 && window->type != WIN_MUC && window->type != WIN_CONFIG && window->type != WIN_XML && window->type != WIN_CONSOLE && window->type != WIN_AI) {
             result = g_slist_append(result, window);
         }
         curr = g_list_next(curr);
@@ -849,6 +867,45 @@ wins_get_prune_wins(void)
     return result;
 }
 
+ProfAiWin*
+wins_get_ai(void)
+{
+    GList* curr = values;
+
+    while (curr) {
+        ProfWin* window = curr->data;
+        if (window->type == WIN_AI) {
+            ProfAiWin* aiwin = (ProfAiWin*)window;
+            assert(aiwin->memcheck == PROFAIWIN_MEMCHECK);
+            return aiwin;
+        }
+        curr = g_list_next(curr);
+    }
+
+    return NULL;
+}
+
+gboolean
+wins_ai_exists(ProfAiWin* const aiwin)
+{
+    if (!aiwin) {
+        return FALSE;
+    }
+
+    GList* curr = values;
+    while (curr) {
+        ProfWin* window = curr->data;
+        if (window->type == WIN_AI) {
+            if ((ProfAiWin*)window == aiwin) {
+                return TRUE;
+            }
+        }
+        curr = g_list_next(curr);
+    }
+
+    return FALSE;
+}
+
 void
 wins_lost_connection(void)
 {

src/ui/window_list.h

@@ -63,6 +63,8 @@ ProfPrivateWin* wins_get_private(const char* const fulljid);
 ProfPluginWin* wins_get_plugin(const char* const tag);
 ProfXMLWin* wins_get_xmlconsole(void);
 ProfVcardWin* wins_get_vcard(void);
+ProfAiWin* wins_get_ai(void);
+gboolean wins_ai_exists(ProfAiWin* const aiwin);
 
 void wins_close_plugin(char* tag);
 

tests/functionaltests/ai_http_stub.c

@@ -0,0 +1,100 @@
+/*
+ * ai_http_stub.c
+ *
+ * Spawns tests/functionaltests/ai_http_stub.py as a child process for
+ * functional tests that exercise the AI client's HTTP code path. The
+ * stub listens on 127.0.0.1 on an OS-chosen port and prints "PORT=<n>"
+ * as its first line; we read it back and hand the port to the caller.
+ */
+
+#include "ai_http_stub.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define STUB_SCRIPT "../tests/functionaltests/ai_http_stub.py"
+#define READLINE_MAX 64
+
+static pid_t stub_pid = 0;
+
+int
+ai_http_stub_start(const char* mode, const char* reply)
+{
+    int pipefd[2];
+    if (pipe(pipefd) != 0) {
+        return 0;
+    }
+
+    pid_t pid = fork();
+    if (pid < 0) {
+        close(pipefd[0]);
+        close(pipefd[1]);
+        return 0;
+    }
+
+    if (pid == 0) {
+        /* Child: redirect stdout to the pipe write end, then exec the stub. */
+        close(pipefd[0]);
+        dup2(pipefd[1], STDOUT_FILENO);
+        close(pipefd[1]);
+
+        if (mode) {
+            setenv("AI_STUB_MODE", mode, 1);
+        }
+        if (reply) {
+            setenv("AI_STUB_REPLY", reply, 1);
+        }
+        /* Argument "0" -> let the OS pick a free port. */
+        execlp("python3", "python3", STUB_SCRIPT, "0", (char*)NULL);
+        /* Falls through on exec failure. */
+        _exit(127);
+    }
+
+    /* Parent: read "PORT=<n>\n" from the child's stdout. */
+    close(pipefd[1]);
+
+    char buf[READLINE_MAX] = { 0 };
+    ssize_t total = 0;
+    while (total < (ssize_t)sizeof(buf) - 1) {
+        ssize_t n = read(pipefd[0], buf + total, sizeof(buf) - 1 - total);
+        if (n <= 0) {
+            break;
+        }
+        total += n;
+        if (memchr(buf, '\n', total)) {
+            break;
+        }
+    }
+    close(pipefd[0]);
+
+    int port = 0;
+    if (sscanf(buf, "PORT=%d", &port) != 1 || port <= 0) {
+        kill(pid, SIGTERM);
+        waitpid(pid, NULL, 0);
+        return 0;
+    }
+
+    stub_pid = pid;
+    return port;
+}
+
+void
+ai_http_stub_stop(void)
+{
+    if (stub_pid <= 0) {
+        return;
+    }
+    kill(stub_pid, SIGTERM);
+    /* Give the stub a moment to exit cleanly, then reap. */
+    int status = 0;
+    pid_t waited = waitpid(stub_pid, &status, 0);
+    (void)waited;
+    (void)status;
+    stub_pid = 0;
+}

tests/functionaltests/ai_http_stub.h

@@ -0,0 +1,25 @@
+#ifndef __H_AI_HTTP_STUB
+#define __H_AI_HTTP_STUB
+
+#include <sys/types.h>
+
+/*
+ * Spawn the Python AI stub script (tests/functionaltests/ai_http_stub.py).
+ *
+ * mode      — one of "ok", "openai", "401", "500", "models" (see the stub
+ *             script). Selects the response body and HTTP status.
+ * reply     — body text used by "ok"/"openai"/"401" modes. Pass NULL for
+ *             the default ("MOCK-REPLY").
+ *
+ * Returns the listening port (>0) on success, 0 on failure. The child's
+ * pid is recorded internally; call ai_http_stub_stop() to terminate it.
+ */
+int ai_http_stub_start(const char* mode, const char* reply);
+
+/*
+ * Send SIGTERM to the most recently spawned stub and reap it.
+ * No-op if no stub is running.
+ */
+void ai_http_stub_stop(void);
+
+#endif

tests/functionaltests/ai_http_stub.py

@@ -0,0 +1,117 @@
+#!/usr/bin/env python3
+"""
+Minimal HTTP stub for AI functional tests.
+
+Listens on 127.0.0.1:<port> and serves canned JSON responses for any POST.
+Behaviour is selected via the URL path and the AI_STUB_MODE environment
+variable, set by the test runner before exec().
+
+Modes:
+  - "ok"     : 200 with a valid OpenAI Responses-API body
+                ({"output":[{"content":[{"text":"...","type":"output_text"}]}]})
+  - "openai" : 200 with a legacy OpenAI Chat Completions body
+                ({"choices":[{"message":{"content":"..."}}]})
+  - "401"    : 401 with an OpenAI-style error envelope
+  - "500"    : 500 with a body that triggers the parse-error fallback
+  - "models" : 200 with a /v1/models list body
+
+The reply text is taken from AI_STUB_REPLY (default: "MOCK-REPLY").
+
+The stub writes its actual listening port to stdout as a single line
+"PORT=<n>" so the parent can read it back, then runs until SIGTERM.
+"""
+import json
+import os
+import sys
+from http.server import HTTPServer, BaseHTTPRequestHandler
+
+
+REPLY = os.environ.get("AI_STUB_REPLY", "MOCK-REPLY")
+MODE = os.environ.get("AI_STUB_MODE", "ok")
+
+
+def _dumps(body: object) -> bytes:
+    """Produce compact JSON without whitespace — profanity's hand-rolled
+    parser does strstr for `"key":"`, which fails when json.dumps inserts
+    a space after the colon by default."""
+    return json.dumps(body, separators=(",", ":")).encode("utf-8")
+
+
+def _body_for(mode: str) -> tuple[int, bytes]:
+    if mode == "ok":
+        body = {
+            "output": [
+                {
+                    "content": [
+                        {"text": REPLY, "type": "output_text"}
+                    ]
+                }
+            ]
+        }
+        return 200, _dumps(body)
+    if mode == "openai":
+        body = {
+            "choices": [
+                {"message": {"role": "assistant", "content": REPLY}}
+            ]
+        }
+        return 200, _dumps(body)
+    if mode == "401":
+        body = {
+            "error": {
+                "message": REPLY,
+                "type": "invalid_request_error",
+                "code": "invalid_api_key",
+            }
+        }
+        return 401, _dumps(body)
+    if mode == "500":
+        return 500, b"<html><body>Internal Server Error</body></html>"
+    if mode == "models":
+        body = {
+            "object": "list",
+            "data": [
+                {"id": "model-a", "object": "model"},
+                {"id": "model-b", "object": "model"},
+                {"id": "model-c", "object": "model"},
+            ],
+        }
+        return 200, _dumps(body)
+    return 200, b"{}"
+
+
+class StubHandler(BaseHTTPRequestHandler):
+    def _send(self):
+        status, body = _body_for(MODE)
+        self.send_response(status)
+        self.send_header("Content-Type", "application/json")
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+    def do_POST(self):
+        length = int(self.headers.get("Content-Length", 0))
+        if length:
+            self.rfile.read(length)
+        self._send()
+
+    def do_GET(self):
+        self._send()
+
+    def log_message(self, fmt, *args):
+        return
+
+
+def main() -> None:
+    port = int(sys.argv[1]) if len(sys.argv) > 1 else 0
+    srv = HTTPServer(("127.0.0.1", port), StubHandler)
+    actual = srv.server_address[1]
+    print(f"PORT={actual}", flush=True)
+    try:
+        srv.serve_forever()
+    except KeyboardInterrupt:
+        pass
+
+
+if __name__ == "__main__":
+    main()

tests/functionaltests/functionaltests.c

@@ -59,6 +59,8 @@
 #ifdef HAVE_SQLITE
 #include "test_export_import.h"
 #endif
+#include "test_ai.h"
+#include "test_ai_http.h"
 
 /* Macro to wrap each test with setup/teardown functions */
 #define PROF_FUNC_TEST(test)                                \
@@ -66,6 +68,14 @@
         #test, test, init_prof_test, close_prof_test, #test \
     }
 
+/* AI tests use a custom init that primes stabber via prof_connect so
+ * stbbr_stop() in close_prof_test() doesn't hang on a never-connected
+ * server thread. See ai_init_test() in test_ai.c. */
+#define PROF_FUNC_TEST_AI(test)                          \
+    {                                                    \
+        #test, test, ai_init_test, close_prof_test, #test \
+    }
+
 #ifdef HAVE_SQLITE
 /* Custom init that sets a non-UTC timezone (POSIX TST-3 = UTC+3) */
 static int
@@ -84,9 +94,9 @@ main(int argc, char* argv[])
     int group = 0; /* 0 = all groups */
     if (argc > 1) {
         group = atoi(argv[1]);
-        if (group < 1 || group > 4) {
+        if (group < 1 || group > 5) {
             fprintf(stderr, "Usage: %s [group]\n", argv[0]);
-            fprintf(stderr, "  group: 1-4 to run specific group, or omit for all\n");
+            fprintf(stderr, "  group: 1-5 to run specific group, or omit for all\n");
             return 1;
         }
     }
@@ -307,6 +317,39 @@ main(int argc, char* argv[])
 #endif
     };
 
+    /* ============================================================
+     * GROUP 5: AI command surface (console + HTTP stub)
+     * Standalone because AI tests don't use stabber's XMPP path; mixing
+     * them with XMPP-bound tests in the same group poisons stabber state
+     * between fixture init/teardown cycles and hangs subsequent
+     * prof_connect() calls.
+     * ============================================================ */
+    const struct CMUnitTest group5_tests[] = {
+        /* Tier A — no network calls */
+        PROF_FUNC_TEST_AI(ai_no_args_shows_help),
+        PROF_FUNC_TEST_AI(ai_providers_lists_defaults),
+        PROF_FUNC_TEST_AI(ai_providers_list_shows_key_status),
+        PROF_FUNC_TEST_AI(ai_set_provider_adds_custom),
+        PROF_FUNC_TEST_AI(ai_set_token_marks_key_set),
+        PROF_FUNC_TEST_AI(ai_start_unknown_provider_errors),
+        PROF_FUNC_TEST_AI(ai_start_without_key_errors),
+        PROF_FUNC_TEST_AI(ai_start_with_key_opens_window),
+        PROF_FUNC_TEST_AI(ai_clear_without_window_errors),
+        PROF_FUNC_TEST_AI(ai_remove_provider_works),
+        PROF_FUNC_TEST_AI(ai_remove_provider_unknown_errors),
+        PROF_FUNC_TEST_AI(ai_set_default_provider_unknown_errors),
+        PROF_FUNC_TEST_AI(ai_set_default_model_updates_provider),
+        PROF_FUNC_TEST_AI(ai_switch_without_window_errors),
+        PROF_FUNC_TEST_AI(ai_bad_subcommand_shows_usage),
+
+        /* Tier B — full request/response through Python HTTP stub */
+        PROF_FUNC_TEST_AI(ai_http_prompt_returns_ok),
+        PROF_FUNC_TEST_AI(ai_http_prompt_openai_format),
+        PROF_FUNC_TEST_AI(ai_http_prompt_401_shows_error),
+        PROF_FUNC_TEST_AI(ai_http_prompt_500_surfaced),
+        PROF_FUNC_TEST_AI(ai_http_models_fetch_lists_models),
+    };
+
     /* Test group registry for easy extension */
     struct
     {
@@ -318,6 +361,7 @@ main(int argc, char* argv[])
         { "Group 2: ExportImport/Receipts", group2_tests, ARRAY_SIZE(group2_tests) },
         { "Group 3: Presence/Disconnect/DBHistory/Message/MUC-DB", group3_tests, ARRAY_SIZE(group3_tests) },
         { "Group 4: Session/MUC/Carbons/MigrationStress", group4_tests, ARRAY_SIZE(group4_tests) },
+        { "Group 5: AI command surface (Tier A + Tier B)", group5_tests, ARRAY_SIZE(group5_tests) },
     };
     const int num_groups = ARRAY_SIZE(groups);
 

tests/functionaltests/proftest.c

@@ -20,7 +20,7 @@
 #include "proftest.h"
 
 /* Number of parallel test groups for CI builds */
-#define TEST_GROUPS 4
+#define TEST_GROUPS 5
 
 /* Number of ports reserved per test group; allows skipping TIME_WAIT ports */
 #define PORTS_PER_GROUP 50

tests/functionaltests/test_ai.c

@@ -0,0 +1,241 @@
+/*
+ * test_ai.c
+ *
+ * Functional tests for the /ai command surface (Tier A — no network).
+ *
+ * These tests interact with profanity through its PTY console and exercise
+ * paths that do not reach libcurl: command parsing, provider registration,
+ * key/setting/default storage, error messages, and AI window creation.
+ *
+ * Tests that require an actual provider HTTP exchange (prompt -> response,
+ * /ai models <provider>, HTTP error envelopes) are out of scope here and
+ * belong in a separate suite backed by a local HTTP stub.
+ */
+
+#include <glib.h>
+#include "prof_cmocka.h"
+#include <stdlib.h>
+#include <string.h>
+
+#include "proftest.h"
+#include "test_ai.h"
+
+int
+ai_init_test(void** state)
+{
+    int ret = init_prof_test(state);
+    if (ret != 0) {
+        return ret;
+    }
+    /* Connect to stabber even though AI tests don't use XMPP. Without this
+     * stabber's accept loop has no client to disconnect on /quit, and
+     * stbbr_stop() in close_prof_test() hangs uninterruptibly when joining
+     * the server thread. */
+    prof_connect();
+    return 0;
+}
+
+void
+ai_no_args_shows_help(void** state)
+{
+    /* `/ai` with no arguments lists the built-in providers and a usage hint. */
+    prof_input("/ai");
+
+    prof_timeout(5);
+    assert_true(prof_output_exact("AI Chat - OpenAI-compatible API client"));
+    assert_true(prof_output_exact("Configured providers:"));
+    assert_true(prof_output_regex("openai"));
+    assert_true(prof_output_regex("perplexity"));
+    assert_true(prof_output_regex("Use '/ai start' to begin a chat"));
+    prof_timeout_reset();
+}
+
+void
+ai_providers_lists_defaults(void** state)
+{
+    /* `/ai providers` (no "list") shows the built-in list with URLs. */
+    prof_input("/ai providers");
+
+    prof_timeout(5);
+    assert_true(prof_output_exact("Available AI providers:"));
+    assert_true(prof_output_regex("openai"));
+    assert_true(prof_output_regex("perplexity"));
+    prof_timeout_reset();
+}
+
+void
+ai_providers_list_shows_key_status(void** state)
+{
+    /* `/ai providers list` lists each configured provider with key status. */
+    prof_input("/ai providers list");
+
+    prof_timeout(5);
+    assert_true(prof_output_exact("Configured providers:"));
+    /* No tokens have been set yet in this fresh session. */
+    assert_true(prof_output_regex("Key: NOT configured"));
+    prof_timeout_reset();
+}
+
+void
+ai_set_provider_adds_custom(void** state)
+{
+    /* Adding a custom provider should make it appear in /ai providers list. */
+    prof_input("/ai set provider mock http://127.0.0.1:1/");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'mock' configured"));
+    prof_timeout_reset();
+
+    prof_input("/ai providers list");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("mock"));
+    assert_true(prof_output_regex("http://127.0.0.1:1/"));
+    prof_timeout_reset();
+}
+
+void
+ai_set_token_marks_key_set(void** state)
+{
+    /* Setting a token must flip the provider's key status to "configured". */
+    prof_input("/ai set token openai sk-fake-test-key");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("API token set for provider: openai"));
+    prof_timeout_reset();
+
+    prof_input("/ai providers list");
+
+    prof_timeout(5);
+    /* openai now shows "Key: configured" while perplexity stays unconfigured. */
+    assert_true(prof_output_regex("Key: configured"));
+    prof_timeout_reset();
+}
+
+void
+ai_start_unknown_provider_errors(void** state)
+{
+    /* Unknown provider name should error out without creating a window. */
+    prof_input("/ai start nope_provider somemodel");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'nope_provider' not found"));
+    prof_timeout_reset();
+}
+
+void
+ai_start_without_key_errors(void** state)
+{
+    /* Known provider without an API key should refuse to start. */
+    prof_input("/ai start openai gpt-4");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("No API key set for provider 'openai'"));
+    prof_timeout_reset();
+}
+
+void
+ai_start_with_key_opens_window(void** state)
+{
+    /* With a token set, /ai start should create a WIN_AI window. */
+    prof_input("/ai set token openai sk-fake-test-key");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("API token set for provider: openai"));
+    prof_timeout_reset();
+
+    prof_input("/ai start openai gpt-4");
+
+    prof_timeout(5);
+    /* /ai start switches focus to the new WIN_AI window; cons_show output
+     * to the console is therefore not the right place to look. The window
+     * itself prints "AI Chat: <provider>/<model>" as its first line. */
+    assert_true(prof_output_regex("AI Chat: openai/gpt-4"));
+    prof_timeout_reset();
+}
+
+void
+ai_clear_without_window_errors(void** state)
+{
+    /* /ai clear from the console (no active AI window) should report nicely. */
+    prof_input("/ai clear");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("No active AI chat window to clear"));
+    prof_timeout_reset();
+}
+
+void
+ai_remove_provider_works(void** state)
+{
+    /* Round-trip: add -> verify present -> remove -> verify gone. */
+    prof_input("/ai set provider tmpprov http://127.0.0.1:2/");
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'tmpprov' configured"));
+    prof_timeout_reset();
+
+    prof_input("/ai remove provider tmpprov");
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'tmpprov' removed"));
+    prof_timeout_reset();
+
+    prof_input("/ai remove provider tmpprov");
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'tmpprov' not found"));
+    prof_timeout_reset();
+}
+
+void
+ai_remove_provider_unknown_errors(void** state)
+{
+    /* Removing a provider that was never added must report "not found". */
+    prof_input("/ai remove provider nonexistent_xyz");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'nonexistent_xyz' not found"));
+    prof_timeout_reset();
+}
+
+void
+ai_set_default_provider_unknown_errors(void** state)
+{
+    /* Setting an unknown default provider should error, not silently accept. */
+    prof_input("/ai set default-provider does_not_exist");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'does_not_exist' not found"));
+    prof_timeout_reset();
+}
+
+void
+ai_set_default_model_updates_provider(void** state)
+{
+    /* Setting a default model is acknowledged on the console. */
+    prof_input("/ai set default-model openai gpt-5-preview");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("Default model for provider 'openai' set to: gpt-5-preview"));
+    prof_timeout_reset();
+}
+
+void
+ai_switch_without_window_errors(void** state)
+{   
+    /* /ai switch with no active AI window should produce an actionable error. */
+    prof_input("/ai switch openai gpt-4");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("No active AI chat window"));
+    prof_timeout_reset();
+}
+
+void
+ai_bad_subcommand_shows_usage(void** state)
+{
+    /* An unknown /ai subcommand should fall through to cons_bad_cmd_usage. */
+    prof_input("/ai not_a_subcommand");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("Invalid usage, see '/help ai'"));
+    prof_timeout_reset();
+}

tests/functionaltests/test_ai.h

@@ -0,0 +1,28 @@
+#ifndef __H_FUNC_TEST_AI
+#define __H_FUNC_TEST_AI
+
+/*
+ * AI tests don't exercise the XMPP path, but the test fixture's
+ * stbbr_stop() hangs indefinitely when no client ever connected to
+ * stabber. ai_init_test wraps init_prof_test with a prof_connect()
+ * so stabber sees a graceful disconnect at teardown.
+ */
+int ai_init_test(void** state);
+
+void ai_no_args_shows_help(void** state);
+void ai_providers_lists_defaults(void** state);
+void ai_providers_list_shows_key_status(void** state);
+void ai_set_provider_adds_custom(void** state);
+void ai_set_token_marks_key_set(void** state);
+void ai_start_unknown_provider_errors(void** state);
+void ai_start_without_key_errors(void** state);
+void ai_start_with_key_opens_window(void** state);
+void ai_clear_without_window_errors(void** state);
+void ai_remove_provider_works(void** state);
+void ai_remove_provider_unknown_errors(void** state);
+void ai_set_default_provider_unknown_errors(void** state);
+void ai_set_default_model_updates_provider(void** state);
+void ai_switch_without_window_errors(void** state);
+void ai_bad_subcommand_shows_usage(void** state);
+
+#endif

tests/functionaltests/test_ai_http.c

@@ -0,0 +1,157 @@
+/*
+ * test_ai_http.c
+ *
+ * Functional tests for the /ai command surface that exercise the libcurl
+ * HTTP code path. A small Python HTTP stub (ai_http_stub.py) is spawned
+ * per-test on a free local port; profanity is configured to point at it
+ * via `/ai set provider`. The stub serves canned JSON whose shape is
+ * controlled via AI_STUB_MODE.
+ *
+ * These tests intentionally do not race the worker thread directly —
+ * they rely on prof_timeout() retries to catch the response once it
+ * propagates back through the AI window.
+ */
+
+#include <glib.h>
+#include "prof_cmocka.h"
+#include <stdlib.h>
+#include <string.h>
+
+#include "proftest.h"
+#include "ai_http_stub.h"
+
+#define WAIT_AI_RESPONSE_SEC 10
+
+/*
+ * Configure profanity to use the spawned stub as a provider named "mock"
+ * with a dummy bearer token, then issue /ai start to open the AI window.
+ * Returns the stub port on success, fails the test on stub-spawn failure.
+ */
+static int
+_setup_mock_provider(const char* mode, const char* reply)
+{
+    int port = ai_http_stub_start(mode, reply);
+    assert_int_not_equal(0, port);
+
+    char cmd[256];
+    g_snprintf(cmd, sizeof(cmd), "/ai set provider mock http://127.0.0.1:%d/", port);
+    prof_input(cmd);
+    prof_timeout(5);
+    assert_true(prof_output_regex("Provider 'mock' configured"));
+    prof_timeout_reset();
+
+    prof_input("/ai set token mock fake-test-token");
+    prof_timeout(5);
+    assert_true(prof_output_regex("API token set for provider: mock"));
+    prof_timeout_reset();
+
+    return port;
+}
+
+void
+ai_http_prompt_returns_ok(void** state)
+{
+    /* Happy path: stub returns Responses API "text" body; reply appears in window. */
+    _setup_mock_provider("ok", "STUB-HELLO");
+
+    prof_input("/ai start mock testmodel");
+    prof_timeout(5);
+    assert_true(prof_output_regex("AI Chat: mock/testmodel"));
+    prof_timeout_reset();
+
+    /* Plain text in AI window goes through cl_ev_send_ai_msg -> ai_send_prompt. */
+    prof_input("hello stub");
+
+    prof_timeout(WAIT_AI_RESPONSE_SEC);
+    assert_true(prof_output_regex("STUB-HELLO"));
+    prof_timeout_reset();
+
+    ai_http_stub_stop();
+}
+
+void
+ai_http_prompt_openai_format(void** state)
+{
+    /* Legacy OpenAI chat completions shape: "choices[].message.content". */
+    _setup_mock_provider("openai", "FROM-CHOICES");
+
+    prof_input("/ai start mock m");
+    prof_timeout(5);
+    assert_true(prof_output_regex("AI Chat: mock/m"));
+    prof_timeout_reset();
+
+    prof_input("anything");
+
+    prof_timeout(WAIT_AI_RESPONSE_SEC);
+    assert_true(prof_output_regex("FROM-CHOICES"));
+    prof_timeout_reset();
+
+    ai_http_stub_stop();
+}
+
+void
+ai_http_prompt_401_shows_error(void** state)
+{
+    /* 401 with an OpenAI-style error envelope.
+     * ai_parse_error_message() should extract the inner message; the AI
+     * window then displays "HTTP 401: <message>". */
+    _setup_mock_provider("401", "Bad token, try another");
+
+    prof_input("/ai start mock m");
+    prof_timeout(5);
+    assert_true(prof_output_regex("AI Chat: mock/m"));
+    prof_timeout_reset();
+
+    prof_input("prompt");
+
+    prof_timeout(WAIT_AI_RESPONSE_SEC);
+    /* Either the parsed message surfaces, or the raw HTTP 401 envelope. */
+    assert_true(prof_output_regex("HTTP 401") && prof_output_regex("Bad token, try another"));
+    prof_timeout_reset();
+
+    ai_http_stub_stop();
+}
+
+void
+ai_http_prompt_500_surfaced(void** state)
+{
+    /* 500 with a non-JSON HTML body. Parser falls back to raw body in HTTP error. */
+    _setup_mock_provider("500", NULL);
+
+    prof_input("/ai start mock m");
+    prof_timeout(5);
+    assert_true(prof_output_regex("AI Chat: mock/m"));
+    prof_timeout_reset();
+
+    prof_input("trigger");
+
+    prof_timeout(WAIT_AI_RESPONSE_SEC);
+    assert_true(prof_output_regex("HTTP 500"));
+    prof_timeout_reset();
+
+    ai_http_stub_stop();
+}
+
+void
+ai_http_models_fetch_lists_models(void** state)
+{
+    /* /v1/models endpoint returns a list of three models. /ai models <p>
+     * caches them silently; /ai models <p> --cached then displays the names. */
+    _setup_mock_provider("models", NULL);
+
+    prof_input("/ai models mock");
+
+    prof_timeout(WAIT_AI_RESPONSE_SEC);
+    assert_true(prof_output_regex("Cached 3 models for provider 'mock'"));
+    prof_timeout_reset();
+
+    prof_input("/ai models mock --cached");
+
+    prof_timeout(5);
+    assert_true(prof_output_regex("model-a"));
+    assert_true(prof_output_regex("model-b"));
+    assert_true(prof_output_regex("model-c"));
+    prof_timeout_reset();
+
+    ai_http_stub_stop();
+}

tests/functionaltests/test_ai_http.h

@@ -0,0 +1,10 @@
+#ifndef __H_FUNC_TEST_AI_HTTP
+#define __H_FUNC_TEST_AI_HTTP
+
+void ai_http_prompt_returns_ok(void** state);
+void ai_http_prompt_openai_format(void** state);
+void ai_http_prompt_401_shows_error(void** state);
+void ai_http_prompt_500_surfaced(void** state);
+void ai_http_models_fetch_lists_models(void** state);
+
+#endif

tests/unittests/test_ai_client.h

@@ -0,0 +1,134 @@
+/*
+ * test_ai_client.h - AI client unit test declarations
+ */
+
+int ai_client_setup(void** state);
+int ai_client_teardown(void** state);
+
+void test_ai_client_init(void** state);
+void test_ai_add_provider(void** state);
+void test_ai_remove_provider(void** state);
+void test_ai_list_providers(void** state);
+void test_ai_set_provider_key(void** state);
+void test_ai_get_provider_key(void** state);
+void test_ai_session_create(void** state);
+void test_ai_session_ref_unref(void** state);
+void test_ai_session_add_message(void** state);
+void test_ai_session_clear_history(void** state);
+void test_ai_session_set_model(void** state);
+void test_ai_json_escape(void** state);
+void test_ai_json_escape_null(void** state);
+void test_ai_json_escape_empty(void** state);
+void test_ai_json_escape_special_chars(void** state);
+void test_ai_json_escape_percent_signs(void** state);
+void test_ai_json_escape_backslash_quote(void** state);
+void test_ai_session_api_key_is_copied(void** state);
+void test_ai_add_provider_update_existing(void** state);
+void test_ai_add_provider_null_name_returns_null(void** state);
+void test_ai_add_provider_null_url_returns_null(void** state);
+void test_ai_session_create_null_provider_returns_null(void** state);
+void test_ai_session_create_null_model_returns_null(void** state);
+void test_ai_session_api_key_null_when_no_key_set(void** state);
+/* Provider autocomplete tests */
+void test_ai_providers_find_forward(void** state);
+void test_ai_providers_find_forward_perplexity(void** state);
+void test_ai_providers_find_forward_custom(void** state);
+void test_ai_providers_find_forward_no_match(void** state);
+void test_ai_providers_find_forward_partial_match(void** state);
+void test_ai_providers_find_next(void** state);
+void test_ai_providers_find_previous(void** state);
+void test_ai_providers_find_null_search_str(void** state);
+void test_ai_providers_find_empty_search_str(void** state);
+void test_ai_providers_find_case_insensitive(void** state);
+/* Provider default model and settings tests */
+void test_ai_set_provider_default_model(void** state);
+void test_ai_get_provider_default_model(void** state);
+void test_ai_set_provider_setting(void** state);
+void test_ai_get_provider_setting(void** state);
+/* Model caching tests */
+void test_ai_models_are_fresh_initial(void** state);
+/* Model parsing tests */
+void test_ai_parse_models_openai_format(void** state);
+void test_ai_parse_models_perplexity_format(void** state);
+void test_ai_parse_models_array_format(void** state);
+void test_ai_parse_models_empty_json(void** state);
+void test_ai_parse_models_null_handling(void** state);
+void test_ai_parse_models_escaped_quotes(void** state);
+void test_ai_parse_models_with_whitespace(void** state);
+/* AI autocomplete integration tests */
+void test_ai_start_provider_autocomplete_only_on_exact(void** state);
+void test_ai_models_find_null_session(void** state);
+void test_ai_models_find_null_provider(void** state);
+void test_ai_providers_find_cycling(void** state);
+
+/* Setup that also initializes prefs for round-trip persistence tests. */
+int ai_client_setup_with_prefs(void** state);
+int ai_client_teardown_with_prefs(void** state);
+
+/* Chat response parser tests (ai_parse_response) */
+void test_ai_parse_response_openai_content(void** state);
+void test_ai_parse_response_perplexity_text(void** state);
+void test_ai_parse_response_text_preferred_over_content(void** state);
+void test_ai_parse_response_escaped_quote(void** state);
+void test_ai_parse_response_newline_escape(void** state);
+void test_ai_parse_response_empty_content(void** state);
+void test_ai_parse_response_missing_field(void** state);
+void test_ai_parse_response_null_input(void** state);
+void test_ai_parse_response_empty_input(void** state);
+void test_ai_parse_response_percent_signs_safe(void** state);
+void test_ai_parse_response_braces_in_content(void** state);
+void test_ai_parse_response_multiline_content(void** state);
+
+/* Error response parser tests (ai_parse_error_message) */
+void test_ai_parse_error_standard_envelope(void** state);
+void test_ai_parse_error_with_escapes(void** state);
+void test_ai_parse_error_no_error_field(void** state);
+void test_ai_parse_error_no_message_field(void** state);
+void test_ai_parse_error_null_input(void** state);
+void test_ai_parse_error_empty_input(void** state);
+void test_ai_parse_error_tab_escape(void** state);
+void test_ai_parse_error_backslash_escape(void** state);
+
+/* Extended JSON escape tests */
+void test_ai_json_escape_backspace(void** state);
+void test_ai_json_escape_formfeed(void** state);
+void test_ai_json_escape_carriage_return(void** state);
+void test_ai_json_escape_all_specials_combined(void** state);
+void test_ai_json_escape_passes_utf8_through(void** state);
+
+/* Autocomplete cycling with many providers */
+void test_ai_providers_find_cycles_through_many(void** state);
+void test_ai_providers_find_previous_walks_backwards(void** state);
+void test_ai_providers_find_wraps_around(void** state);
+
+/* Session edge cases */
+void test_ai_session_add_message_null_session_no_crash(void** state);
+void test_ai_session_add_message_null_role_no_crash(void** state);
+void test_ai_session_add_message_null_content_no_crash(void** state);
+void test_ai_session_history_preserves_large_order(void** state);
+void test_ai_session_clear_empty_history(void** state);
+void test_ai_session_set_model_null_keeps_old(void** state);
+void test_ai_session_unref_null_no_crash(void** state);
+void test_ai_session_ref_null_returns_null(void** state);
+
+/* Provider edge cases */
+void test_ai_get_provider_null_returns_null(void** state);
+void test_ai_remove_provider_null_returns_false(void** state);
+void test_ai_remove_provider_twice_second_fails(void** state);
+void test_ai_provider_survives_via_session_after_removal(void** state);
+
+/* Settings edge cases */
+void test_ai_settings_multiple_keys_independent(void** state);
+void test_ai_settings_get_missing_returns_null(void** state);
+void test_ai_settings_isolated_between_providers(void** state);
+
+/* Model parsing edge cases */
+void test_ai_parse_models_data_not_array(void** state);
+void test_ai_parse_models_empty_data_array(void** state);
+void test_ai_parse_models_id_outside_data_ignored(void** state);
+void test_ai_parse_models_multiple_models(void** state);
+
+/* Prefs round-trip tests */
+void test_ai_prefs_round_trip_api_key(void** state);
+void test_ai_prefs_round_trip_remove_key(void** state);
+void test_ai_prefs_multiple_providers_persist(void** state);

tests/unittests/ui/stub_ai.c

@@ -0,0 +1,41 @@
+/*
+ * stub_ai.c - Stubs for AI window functions
+ */
+
+#include "ui/window.h"
+#include "ai/ai_client.h"
+
+ProfWin*
+win_create_ai(AISession* session)
+{
+    /* Return NULL to simulate failure in unit tests */
+    (void)session;
+    return NULL;
+}
+
+void
+aiwin_display_response(ProfAiWin* win, const char* response)
+{
+    /* Stub: do nothing */
+    (void)win;
+    (void)response;
+}
+
+void
+aiwin_display_error(ProfAiWin* win, const char* error_msg)
+{
+    /* Stub: do nothing */
+    (void)win;
+    (void)error_msg;
+}
+
+void
+win_print_outgoing(ProfWin* window, const char* show_char, const char* const id, const char* const replace_id, const char* const message)
+{
+    /* Stub: do nothing */
+    (void)window;
+    (void)show_char;
+    (void)id;
+    (void)replace_id;
+    (void)message;
+}

tests/unittests/unittests.c

@@ -36,6 +36,7 @@
 #include "test_form.h"
 #include "test_callbacks.h"
 #include "test_plugins_disco.h"
+#include "test_ai_client.h"
 #include "test_database_export.h"
 #include "test_database_stress.h"
 
@@ -659,6 +660,121 @@ main(int argc, char* argv[])
         cmocka_unit_test_setup_teardown(test_cmd_force_encryption_invalid_policy, load_preferences, close_preferences),
         cmocka_unit_test_setup_teardown(test_allow_unencrypted_message_invalid_mode, load_preferences, close_preferences),
 
+        // AI client tests
+        cmocka_unit_test_setup_teardown(test_ai_client_init, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_add_provider, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_remove_provider, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_list_providers, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_set_provider_key, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_get_provider_key, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_create, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_ref_unref, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_add_message, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_clear_history, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_set_model, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_api_key_is_copied, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_add_provider_update_existing, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_add_provider_null_name_returns_null, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_add_provider_null_url_returns_null, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_create_null_provider_returns_null, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_create_null_model_returns_null, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_api_key_null_when_no_key_set, ai_client_setup, ai_client_teardown),
+        /* Provider autocomplete tests */
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_forward, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_forward_perplexity, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_forward_custom, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_forward_no_match, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_forward_partial_match, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_next, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_previous, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_null_search_str, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_empty_search_str, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_case_insensitive, ai_client_setup, ai_client_teardown),
+        /* Provider default model and settings tests */
+        cmocka_unit_test_setup_teardown(test_ai_set_provider_default_model, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_get_provider_default_model, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_set_provider_setting, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_get_provider_setting, ai_client_setup, ai_client_teardown),
+        /* Model caching tests */
+        cmocka_unit_test_setup_teardown(test_ai_models_are_fresh_initial, ai_client_setup, ai_client_teardown),
+        /* Model parsing tests */
+        cmocka_unit_test(test_ai_parse_models_openai_format),
+        cmocka_unit_test(test_ai_parse_models_perplexity_format),
+        cmocka_unit_test(test_ai_parse_models_array_format),
+        cmocka_unit_test(test_ai_parse_models_empty_json),
+        cmocka_unit_test(test_ai_parse_models_null_handling),
+        cmocka_unit_test(test_ai_parse_models_escaped_quotes),
+        cmocka_unit_test(test_ai_parse_models_with_whitespace),
+        /* AI autocomplete integration tests */
+        cmocka_unit_test_setup_teardown(test_ai_start_provider_autocomplete_only_on_exact, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_models_find_null_session, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_models_find_null_provider, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_cycling, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test(test_ai_json_escape),
+        cmocka_unit_test(test_ai_json_escape_null),
+        cmocka_unit_test(test_ai_json_escape_empty),
+        cmocka_unit_test(test_ai_json_escape_special_chars),
+        cmocka_unit_test(test_ai_json_escape_percent_signs),
+        cmocka_unit_test(test_ai_json_escape_backslash_quote),
+        /* Chat response parser */
+        cmocka_unit_test(test_ai_parse_response_openai_content),
+        cmocka_unit_test(test_ai_parse_response_perplexity_text),
+        cmocka_unit_test(test_ai_parse_response_text_preferred_over_content),
+        cmocka_unit_test(test_ai_parse_response_escaped_quote),
+        cmocka_unit_test(test_ai_parse_response_newline_escape),
+        cmocka_unit_test(test_ai_parse_response_empty_content),
+        cmocka_unit_test(test_ai_parse_response_missing_field),
+        cmocka_unit_test(test_ai_parse_response_null_input),
+        cmocka_unit_test(test_ai_parse_response_empty_input),
+        cmocka_unit_test(test_ai_parse_response_percent_signs_safe),
+        cmocka_unit_test(test_ai_parse_response_braces_in_content),
+        cmocka_unit_test(test_ai_parse_response_multiline_content),
+        /* Error response parser */
+        cmocka_unit_test(test_ai_parse_error_standard_envelope),
+        cmocka_unit_test(test_ai_parse_error_with_escapes),
+        cmocka_unit_test(test_ai_parse_error_no_error_field),
+        cmocka_unit_test(test_ai_parse_error_no_message_field),
+        cmocka_unit_test(test_ai_parse_error_null_input),
+        cmocka_unit_test(test_ai_parse_error_empty_input),
+        cmocka_unit_test(test_ai_parse_error_tab_escape),
+        cmocka_unit_test(test_ai_parse_error_backslash_escape),
+        /* Extended JSON escape coverage */
+        cmocka_unit_test(test_ai_json_escape_backspace),
+        cmocka_unit_test(test_ai_json_escape_formfeed),
+        cmocka_unit_test(test_ai_json_escape_carriage_return),
+        cmocka_unit_test(test_ai_json_escape_all_specials_combined),
+        cmocka_unit_test(test_ai_json_escape_passes_utf8_through),
+        /* Autocomplete cycling */
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_cycles_through_many, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_previous_walks_backwards, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_providers_find_wraps_around, ai_client_setup, ai_client_teardown),
+        /* Session edge cases */
+        cmocka_unit_test_setup_teardown(test_ai_session_add_message_null_session_no_crash, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_add_message_null_role_no_crash, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_add_message_null_content_no_crash, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_history_preserves_large_order, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_clear_empty_history, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_set_model_null_keeps_old, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_unref_null_no_crash, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_session_ref_null_returns_null, ai_client_setup, ai_client_teardown),
+        /* Provider edge cases */
+        cmocka_unit_test_setup_teardown(test_ai_get_provider_null_returns_null, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_remove_provider_null_returns_false, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_remove_provider_twice_second_fails, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_provider_survives_via_session_after_removal, ai_client_setup, ai_client_teardown),
+        /* Settings */
+        cmocka_unit_test_setup_teardown(test_ai_settings_multiple_keys_independent, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_settings_get_missing_returns_null, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_settings_isolated_between_providers, ai_client_setup, ai_client_teardown),
+        /* Model parsing edge cases */
+        cmocka_unit_test_setup_teardown(test_ai_parse_models_data_not_array, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_parse_models_empty_data_array, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_parse_models_id_outside_data_ignored, ai_client_setup, ai_client_teardown),
+        cmocka_unit_test_setup_teardown(test_ai_parse_models_multiple_models, ai_client_setup, ai_client_teardown),
+        /* Prefs round-trip (uses prefs+ai setup) */
+        cmocka_unit_test_setup_teardown(test_ai_prefs_round_trip_api_key, ai_client_setup_with_prefs, ai_client_teardown_with_prefs),
+        cmocka_unit_test_setup_teardown(test_ai_prefs_round_trip_remove_key, ai_client_setup_with_prefs, ai_client_teardown_with_prefs),
+        cmocka_unit_test_setup_teardown(test_ai_prefs_multiple_providers_persist, ai_client_setup_with_prefs, ai_client_teardown_with_prefs),
         // Flatfile export/import round-trip
         cmocka_unit_test(test_ff_roundtrip_simple_chat),
         cmocka_unit_test(test_ff_roundtrip_with_all_metadata),