feat: add IIntentExtractor interface and config fields (GIT-97)

src/domain/interfaces/IHookConfig.ts

@@ -27,8 +27,16 @@ export interface IPromptSubmitConfig {
   readonly enabled: boolean;
   /** Whether to record prompts as memories. Reserved — not yet wired to handler. */
   readonly recordPrompts: boolean;
-  /** Whether to surface context memories per prompt. Reserved — not yet wired to handler. */
+  /** Whether to surface context memories per prompt. */
   readonly surfaceContext: boolean;
+  /** Enable LLM-based intent extraction for smarter memory retrieval. */
+  readonly extractIntent: boolean;
+  /** Timeout in ms for intent extraction LLM call. Default: 3000. Must be under hook timeout (10s). */
+  readonly intentTimeout: number;
+  /** Minimum word count to trigger intent extraction. Default: 5. */
+  readonly minWords: number;
+  /** Maximum memories to return. Default: 20. */
+  readonly memoryLimit: number;
 }
 
 export interface IPostCommitConfig {

src/domain/interfaces/IIntentExtractor.ts

@@ -0,0 +1,72 @@
+/**
+ * IIntentExtractor
+ *
+ * Interface for extracting searchable keywords from user prompts.
+ * Used by the prompt-submit hook to query memories with intent-based filtering.
+ */
+
+/**
+ * Input to the intent extraction service.
+ */
+export interface IIntentExtractorInput {
+  /** The user's prompt text. */
+  readonly prompt: string;
+}
+
+/**
+ * Reason for skipping intent extraction.
+ */
+export type IntentSkipReason =
+  | 'too_short'
+  | 'confirmation'
+  | 'no_llm'
+  | 'llm_skip'
+  | 'timeout'
+  | 'error';
+
+/**
+ * Result of intent extraction.
+ *
+ * This is a discriminated union keyed by `skipped`:
+ * - When `skipped` is `true`, `intent` is always `null` and `reason` is defined.
+ * - When `skipped` is `false`, `intent` may be a string, and `reason` is undefined.
+ */
+export type IIntentExtractorResult =
+  | {
+      /** Whether extraction was skipped. */
+      readonly skipped: true;
+      /** Always null when extraction is skipped. */
+      readonly intent: null;
+      /**
+       * Reason for skipping.
+       * - 'too_short': Prompt has fewer words than minWords threshold.
+       * - 'confirmation': Prompt is a simple confirmation (yes/no/ok/etc).
+       * - 'no_llm': No LLM client available.
+       * - 'llm_skip': LLM returned SKIP (no extractable keywords).
+       * - 'timeout': LLM call timed out.
+       * - 'error': LLM call failed with error.
+       */
+      readonly reason: IntentSkipReason;
+    }
+  | {
+      /** Whether extraction was skipped. */
+      readonly skipped: false;
+      /** Extracted keywords for memory search. */
+      readonly intent: string;
+      /** Reason is not present when extraction succeeded. */
+      readonly reason?: undefined;
+    };
+
+/**
+ * Service for extracting searchable keywords from user prompts.
+ */
+export interface IIntentExtractor {
+  /**
+   * Extract searchable keywords from a user prompt.
+   * Returns keywords suitable for memory search, or null if skipped.
+   *
+   * @param input - The prompt to extract intent from.
+   * @returns Extracted keywords or skip indicator.
+   */
+  extract(input: IIntentExtractorInput): Promise<IIntentExtractorResult>;
+}

src/hooks/utils/config.ts

@@ -42,7 +42,15 @@ const DEFAULTS: IHookConfig = {
     enabled: true,
     sessionStart: { enabled: true, memoryLimit: 20 },
     sessionStop: { enabled: true, autoExtract: true, threshold: 3 },
-    promptSubmit: { enabled: false, recordPrompts: false, surfaceContext: true },
+    promptSubmit: {
+      enabled: true,
+      recordPrompts: false,
+      surfaceContext: true,
+      extractIntent: true,
+      intentTimeout: 3000,
+      minWords: 5,
+      memoryLimit: 20,
+    },
     postCommit: { enabled: true },
     commitMsg: {
       enabled: true,

tests/unit/hooks/utils/config.test.ts

@@ -74,9 +74,13 @@ describe('config', () => {
       assert.equal(config.hooks.sessionStop.enabled, true);
       assert.equal(config.hooks.sessionStop.autoExtract, true);
       assert.equal(config.hooks.sessionStop.threshold, 3);
-      assert.equal(config.hooks.promptSubmit.enabled, false);
+      assert.equal(config.hooks.promptSubmit.enabled, true);
       assert.equal(config.hooks.promptSubmit.recordPrompts, false);
       assert.equal(config.hooks.promptSubmit.surfaceContext, true);
+      assert.equal(config.hooks.promptSubmit.extractIntent, true);
+      assert.equal(config.hooks.promptSubmit.intentTimeout, 3000);
+      assert.equal(config.hooks.promptSubmit.minWords, 5);
+      assert.equal(config.hooks.promptSubmit.memoryLimit, 20);
     });
 
     it('should read and merge config from .git-mem/.git-mem.yaml', () => {