fix(search): newest-first context, session lookup, jsts split, ID disambiguation

src/cli/handlers/session-init.ts

@@ -23,7 +23,9 @@ export const sessionInitHandler: EventHandler = {
       return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
     }
 
-    const { sessionId, cwd, prompt: rawPrompt } = input;
+    const { sessionId, prompt: rawPrompt } = input;
+    // Use same fallback as context handler to ensure consistent project key resolution
+    const cwd = input.cwd ?? process.cwd();
 
     // Guard: Codex CLI and other platforms may not provide a session_id (#744)
     if (!sessionId) {

src/servers/mcp-server.ts

@@ -225,14 +225,14 @@ async function ensureWorkerConnection(): Promise<boolean> {
     if (!started) {
       logger.error(
         'SYSTEM',
-        'Worker auto-start returned false — MCP tools that require the worker (search, timeline, get_observations) will fail until the worker is running. Check earlier log lines for the specific failure reason (Bun not found, missing worker bundle, port conflict, etc.).'
+        'Worker auto-start returned false — MCP tools that require the worker (search, timeline, get_observations, get_sessions, get_prompts) will fail until the worker is running. Check earlier log lines for the specific failure reason (Bun not found, missing worker bundle, port conflict, etc.).'
       );
     }
     return started;
   } catch (error) {
     logger.error(
       'SYSTEM',
-      'Worker auto-start threw — MCP tools that require the worker (search, timeline, get_observations) will fail until the worker is running.',
+      'Worker auto-start threw — MCP tools that require the worker (search, timeline, get_observations, get_sessions, get_prompts) will fail until the worker is running.',
       undefined,
       error as Error
     );
@@ -250,7 +250,10 @@ const tools = [
     description: `3-LAYER WORKFLOW (ALWAYS FOLLOW):
 1. search(query) → Get index with IDs (~50-100 tokens/result)
 2. timeline(anchor=ID) → Get context around interesting results
-3. get_observations([IDs]) → Fetch full details ONLY for filtered IDs
+3. Fetch full details ONLY for filtered IDs using the matching tool:
+   - Observation IDs (emoji-prefixed): get_observations([IDs])
+   - Session IDs (S-prefixed, e.g. S42): get_sessions([IDs])
+   - Prompt IDs (from prompt results): get_prompts([IDs])
 NEVER fetch full details without filtering first. 10x token savings.`,
     inputSchema: {
       type: 'object',
@@ -271,9 +274,11 @@ NEVER fetch full details without filtering first. 10x token savings.`,
    \`timeline(anchor=<ID>, depth_before=3, depth_after=3)\`
    Returns: Chronological context showing what was happening
 
-3. **Fetch** - Get full details ONLY for relevant IDs
-   \`get_observations(ids=[...])\`  # ALWAYS batch for 2+ items
-   Returns: Complete details (~500-1000 tokens/result)
+3. **Fetch** - Get full details ONLY for relevant IDs (use the right tool for each ID type)
+   - \`get_observations(ids=[...])\` for observation IDs (emoji-prefixed in timeline)
+   - \`get_sessions(ids=[...])\` for session IDs (S-prefixed, e.g. S42)
+   - \`get_prompts(ids=[...])\` for user prompt IDs
+   ALWAYS batch for 2+ items. Returns ~500-1000 tokens/result.
 
 **Why:** 10x token savings. Never fetch full details without filtering first.`
       }]
@@ -323,7 +328,7 @@ NEVER fetch full details without filtering first. 10x token savings.`,
   },
   {
     name: 'get_observations',
-    description: 'Step 3: Fetch full details for filtered IDs. Params: ids (array of observation IDs, required), orderBy, limit, project',
+    description: 'Fetch full observation details by IDs (numeric IDs from search results prefixed with observation emoji icons). Params: ids (array of observation IDs, required), orderBy, limit, project',
     inputSchema: {
       type: 'object',
       properties: {
@@ -340,6 +345,44 @@ NEVER fetch full details without filtering first. 10x token savings.`,
       return await callWorkerAPIPost('/api/observations/batch', args);
     }
   },
+  {
+    name: 'get_sessions',
+    description: 'Fetch full session summary details by IDs (numeric IDs from timeline prefixed with "S", e.g. S42). Params: ids (array of session summary IDs, required), orderBy, limit, project',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        ids: {
+          type: 'array',
+          items: { type: 'number' },
+          description: 'Array of session summary IDs to fetch (required)'
+        }
+      },
+      required: ['ids'],
+      additionalProperties: true
+    },
+    handler: async (args: any) => {
+      return await callWorkerAPIPost('/api/sessions/batch', args);
+    }
+  },
+  {
+    name: 'get_prompts',
+    description: 'Fetch full user prompt details by IDs (numeric IDs from search results tagged as prompts). Params: ids (array of user_prompt IDs, required), orderBy, limit, project',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        ids: {
+          type: 'array',
+          items: { type: 'number' },
+          description: 'Array of user prompt IDs to fetch (required)'
+        }
+      },
+      required: ['ids'],
+      additionalProperties: true
+    },
+    handler: async (args: any) => {
+      return await callWorkerAPIPost('/api/prompts/batch', args);
+    }
+  },
   {
     name: 'smart_search',
     description: 'Search codebase for symbols, functions, classes using tree-sitter AST parsing. Returns folded structural views with token counts. Use path parameter to scope the search.',

src/services/context/ObservationCompiler.ts

@@ -315,11 +315,12 @@ export function buildTimeline(
     ...summaries.map(summary => ({ type: 'summary' as const, data: summary }))
   ];
 
-  // Sort chronologically
+  // Sort newest-first so that when Claude Code truncates SessionStart output
+  // to 2KB, the user sees the most recent (and most relevant) data
   timeline.sort((a, b) => {
     const aEpoch = a.type === 'observation' ? a.data.created_at_epoch : a.data.displayEpoch;
     const bEpoch = b.type === 'observation' ? b.data.created_at_epoch : b.data.displayEpoch;
-    return aEpoch - bEpoch;
+    return bEpoch - aEpoch;
   });
 
   return timeline;

src/services/context/formatters/AgentFormatter.ts

@@ -50,7 +50,7 @@ export function renderAgentLegend(): string[] {
   return [
     `Legend: 🎯session ${typeLegendItems}`,
     `Format: ID TIME TYPE TITLE`,
-    `Fetch details: get_observations([IDs]) | Search: mem-search skill`,
+    `Fetch: get_observations([IDs]) for observations, get_sessions([IDs]) for S-prefixed sessions, get_prompts([IDs]) for prompts | Search: mem-search skill`,
     ''
   ];
 }
@@ -215,7 +215,7 @@ export function renderAgentFooter(totalDiscoveryTokens: number, totalReadTokens:
   const workTokensK = Math.round(totalDiscoveryTokens / 1000);
   return [
     '',
-    `Access ${workTokensK}k tokens of past work via get_observations([IDs]) or mem-search skill.`
+    `Access ${workTokensK}k tokens of past work: get_observations([IDs]) for observations, get_sessions([IDs]) for sessions, get_prompts([IDs]) for prompts, or mem-search skill.`
   ];
 }
 

src/services/context/formatters/HumanFormatter.ts

@@ -74,7 +74,7 @@ export function renderHumanContextIndex(): string[] {
     `${colors.dim}Context Index: This semantic index (titles, types, files, tokens) is usually sufficient to understand past work.${colors.reset}`,
     '',
     `${colors.dim}When you need implementation details, rationale, or debugging context:${colors.reset}`,
-    `${colors.dim}  - Fetch by ID: get_observations([IDs]) for observations visible in this index${colors.reset}`,
+    `${colors.dim}  - Fetch by ID: get_observations([IDs]) for observations, get_sessions([IDs]) for sessions, get_prompts([IDs]) for prompts${colors.reset}`,
     `${colors.dim}  - Search history: Use the mem-search skill for past decisions, bugs, and deeper research${colors.reset}`,
     `${colors.dim}  - Trust this index over re-reading code for past decisions and learnings${colors.reset}`,
     ''

src/services/context/sections/TimelineRenderer.ts

@@ -30,11 +30,11 @@ export function groupTimelineByDay(timeline: TimelineItem[]): Map<string, Timeli
     itemsByDay.get(day)!.push(item);
   }
 
-  // Sort days chronologically
+  // Sort days newest-first so truncated output shows recent data
   const sortedEntries = Array.from(itemsByDay.entries()).sort((a, b) => {
     const aDate = new Date(a[0]).getTime();
     const bDate = new Date(b[0]).getTime();
-    return aDate - bDate;
+    return bDate - aDate;
   });
 
   return new Map(sortedEntries);

src/services/smart-file-read/parser.ts

@@ -319,17 +319,25 @@ export function resolveGrammarPathWithFallback(language: string, projectRoot?: s
 
 // --- Query patterns (declarative symbol extraction) ---
 
-const QUERIES: Record<string, string> = {
-  jsts: `
+// Shared base for JS and TS: function, class, method, import, export
+const JSTS_BASE_QUERY = `
 (function_declaration name: (identifier) @name) @func
 (lexical_declaration (variable_declarator name: (identifier) @name value: [(arrow_function) (function_expression)])) @const_func
 (class_declaration name: (type_identifier) @name) @cls
 (method_definition name: (property_identifier) @name) @method
+(import_statement) @imp
+(export_statement) @exp
+`;
+
+const QUERIES: Record<string, string> = {
+  // JavaScript: only node types that exist in tree-sitter-javascript grammar
+  javascript: JSTS_BASE_QUERY,
+
+  // TypeScript: extends JS base with TS-only node types (interface, type alias, enum)
+  typescript: `${JSTS_BASE_QUERY}
 (interface_declaration name: (type_identifier) @name) @iface
 (type_alias_declaration name: (type_identifier) @name) @tdef
 (enum_declaration name: (identifier) @name) @enm
-(import_statement) @imp
-(export_statement) @exp
 `,
 
   python: `
@@ -490,9 +498,10 @@ const QUERIES: Record<string, string> = {
 function getQueryKey(language: string): string {
   switch (language) {
     case "javascript":
+      return "javascript";
     case "typescript":
     case "tsx":
-      return "jsts";
+      return "typescript";
     case "python": return "python";
     case "go": return "go";
     case "rust": return "rust";

src/services/sqlite/observations/store.ts

@@ -6,7 +6,6 @@
 import { createHash } from 'crypto';
 import { Database } from 'bun:sqlite';
 import { logger } from '../../../utils/logger.js';
-import { getProjectContext } from '../../../utils/project-name.js';
 import type { ObservationInput, StoreObservationResult } from './types.js';
 
 /** Deduplication window: observations with the same content hash within this window are skipped */
@@ -61,8 +60,11 @@ export function storeObservation(
   const timestampEpoch = overrideTimestampEpoch ?? Date.now();
   const timestampIso = new Date(timestampEpoch).toISOString();
 
-  // Guard against empty project string (race condition where project isn't set yet)
-  const resolvedProject = project || getProjectContext(process.cwd()).primary;
+  // Guard against empty project string (race condition where project isn't set yet).
+  // Use 'unknown-project' instead of getProjectContext(process.cwd()) because the
+  // worker process's cwd is not the user's project directory, which would cause a
+  // project-key mismatch between writes and reads (#1918).
+  const resolvedProject = project || 'unknown-project';
 
   // Content-hash deduplication
   const contentHash = computeObservationContentHash(memorySessionId, observation.title, observation.narrative);

src/services/worker/http/routes/DataRoutes.ts

@@ -44,8 +44,10 @@ export class DataRoutes extends BaseRouteHandler {
     app.get('/api/observations/by-file', this.handleGetObservationsByFile.bind(this));
     app.post('/api/observations/batch', this.handleGetObservationsByIds.bind(this));
     app.get('/api/session/:id', this.handleGetSessionById.bind(this));
+    app.post('/api/sessions/batch', this.handleGetSessionSummariesByIds.bind(this));
     app.post('/api/sdk-sessions/batch', this.handleGetSdkSessionsByIds.bind(this));
     app.get('/api/prompt/:id', this.handleGetPromptById.bind(this));
+    app.post('/api/prompts/batch', this.handleGetPromptsByIds.bind(this));
 
     // Metadata endpoints
     app.get('/api/stats', this.handleGetStats.bind(this));
@@ -187,6 +189,40 @@ export class DataRoutes extends BaseRouteHandler {
     res.json(sessions[0]);
   });
 
+  /**
+   * Get session summaries by array of IDs
+   * POST /api/sessions/batch
+   * Body: { ids: number[], orderBy?: 'date_desc' | 'date_asc', limit?: number, project?: string }
+   */
+  private handleGetSessionSummariesByIds = this.wrapHandler((req: Request, res: Response): void => {
+    let { ids, orderBy, limit, project } = req.body;
+
+    // Coerce string-encoded arrays from MCP clients (e.g. "[1,2,3]" or "1,2,3")
+    if (typeof ids === 'string') {
+      try { ids = JSON.parse(ids); } catch { ids = ids.split(',').map(Number); }
+    }
+
+    if (!ids || !Array.isArray(ids)) {
+      this.badRequest(res, 'ids must be an array of numbers');
+      return;
+    }
+
+    if (ids.length === 0) {
+      res.json([]);
+      return;
+    }
+
+    if (!ids.every((id: any) => typeof id === 'number' && Number.isInteger(id))) {
+      this.badRequest(res, 'All ids must be integers');
+      return;
+    }
+
+    const store = this.dbManager.getSessionStore();
+    const sessions = store.getSessionSummariesByIds(ids, { orderBy, limit, project });
+
+    res.json(sessions);
+  });
+
   /**
    * Get SDK sessions by SDK session IDs
    * POST /api/sdk-sessions/batch
@@ -229,6 +265,40 @@ export class DataRoutes extends BaseRouteHandler {
     res.json(prompts[0]);
   });
 
+  /**
+   * Get user prompts by array of IDs
+   * POST /api/prompts/batch
+   * Body: { ids: number[], orderBy?: 'date_desc' | 'date_asc', limit?: number, project?: string }
+   */
+  private handleGetPromptsByIds = this.wrapHandler((req: Request, res: Response): void => {
+    let { ids, orderBy, limit, project } = req.body;
+
+    // Coerce string-encoded arrays from MCP clients (e.g. "[1,2,3]" or "1,2,3")
+    if (typeof ids === 'string') {
+      try { ids = JSON.parse(ids); } catch { ids = ids.split(',').map(Number); }
+    }
+
+    if (!ids || !Array.isArray(ids)) {
+      this.badRequest(res, 'ids must be an array of numbers');
+      return;
+    }
+
+    if (ids.length === 0) {
+      res.json([]);
+      return;
+    }
+
+    if (!ids.every((id: any) => typeof id === 'number' && Number.isInteger(id))) {
+      this.badRequest(res, 'All ids must be integers');
+      return;
+    }
+
+    const store = this.dbManager.getSessionStore();
+    const prompts = store.getUserPromptsByIds(ids, { orderBy, limit, project });
+
+    res.json(prompts);
+  });
+
   /**
    * Get database statistics (with worker metadata)
    */