feat: Persist agent prompt in DB so getAgentPrompt survives log cleanup

The `getAgentPrompt` tRPC procedure previously read exclusively from
`.cw/agent-logs/<name>/PROMPT.md`. Once the cleanup-manager removes
that directory, the prompt is gone forever.

Adds a `prompt` text column to the `agents` table and writes the fully
assembled prompt (including workspace layout, inter-agent comms, and
preview sections) to the DB in the same `repository.update()` call
that saves pid/outputFilePath after spawn.

`getAgentPrompt` now reads from DB first (`agent.prompt`) and falls
back to the filesystem only for agents spawned before this change.

Addresses review comment [MMcmVlEK16bBfkJuXvG6h].

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/server/agent/manager.ts

@@ -328,7 +328,7 @@ export class MultiProviderAgentManager implements AgentManager {
       this.createLogChunkCallback(agentId, alias, 1),
     );
 
-    await this.repository.update(agentId, { pid, outputFilePath });
+    await this.repository.update(agentId, { pid, outputFilePath, prompt });
 
     // Write spawn diagnostic file for post-execution verification
     const diagnostic = {
@@ -1086,6 +1086,7 @@ export class MultiProviderAgentManager implements AgentManager {
     updatedAt: Date;
     userDismissedAt?: Date | null;
     exitCode?: number | null;
+    prompt?: string | null;
   }): AgentInfo {
     return {
       id: agent.id,
@@ -1102,6 +1103,7 @@ export class MultiProviderAgentManager implements AgentManager {
       updatedAt: agent.updatedAt,
       userDismissedAt: agent.userDismissedAt,
       exitCode: agent.exitCode ?? null,
+      prompt: agent.prompt ?? null,
     };
   }
 }

apps/server/agent/mock-manager.ts

@@ -143,6 +143,7 @@ export class MockAgentManager implements AgentManager {
       createdAt: now,
       updatedAt: now,
       exitCode: null,
+      prompt: null,
     };
 
     const record: MockAgentRecord = {

apps/server/agent/types.ts

@@ -95,6 +95,8 @@ export interface AgentInfo {
   userDismissedAt?: Date | null;
   /** Process exit code — null while running or if not yet exited */
   exitCode: number | null;
+  /** Full assembled prompt passed to the agent process — null for agents spawned before DB persistence */
+  prompt: string | null;
 }
 
 /**

apps/server/db/repositories/agent-repository.ts

@@ -45,6 +45,7 @@ export interface UpdateAgentData {
   accountId?: string | null;
   pid?: number | null;
   exitCode?: number | null;
+  prompt?: string | null;
   outputFilePath?: string | null;
   result?: string | null;
   pendingQuestions?: string | null;

apps/server/db/schema.ts

@@ -265,6 +265,7 @@ export const agents = sqliteTable('agents', {
     .default('execute'),
   pid: integer('pid'),
   exitCode: integer('exit_code'), // Process exit code for debugging crashes
+  prompt: text('prompt'), // Full assembled prompt passed to the agent process (persisted for durability after log cleanup)
   outputFilePath: text('output_file_path'),
   result: text('result'),
   pendingQuestions: text('pending_questions'),

apps/server/dispatch/manager.test.ts

@@ -71,6 +71,7 @@ function createMockAgentManager(
         createdAt: new Date(),
         updatedAt: new Date(),
         exitCode: null,
+        prompt: null,
       };
       mockAgents.push(newAgent);
       return newAgent;
@@ -103,6 +104,7 @@ function createIdleAgent(id: string, name: string): AgentInfo {
     createdAt: new Date(),
     updatedAt: new Date(),
     exitCode: null,
+    prompt: null,
   };
 }
 

apps/server/drizzle/0031_icy_silvermane.sql

@@ -0,0 +1 @@
+ALTER TABLE `agents` ADD `prompt` text;

apps/server/drizzle/meta/_journal.json

@@ -218,6 +218,13 @@
       "when": 1772150400000,
       "tag": "0030_remove_task_approval",
       "breakpoints": true
+    },
+    {
+      "idx": 31,
+      "version": "6",
+      "when": 1772798869413,
+      "tag": "0031_icy_silvermane",
+      "breakpoints": true
     }
   ]
 }

apps/server/test/integration/crash-race-condition.test.ts

@@ -32,6 +32,7 @@ interface TestAgent {
   initiativeId: string | null;
   userDismissedAt: Date | null;
   exitCode: number | null;
+  prompt: string | null;
 }
 
 describe('Crash marking race condition', () => {
@@ -72,7 +73,8 @@ describe('Crash marking race condition', () => {
       pendingQuestions: null,
       initiativeId: 'init-1',
       userDismissedAt: null,
-      exitCode: null
+      exitCode: null,
+      prompt: null,
     };
 
     // Mock repository that tracks all update calls

apps/server/trpc/routers/agent.test.ts

@@ -50,6 +50,7 @@ function makeAgentInfo(overrides: Record<string, unknown> = {}) {
     updatedAt: new Date('2026-01-01T00:00:00Z'),
     userDismissedAt: null,
     exitCode: null,
+    prompt: null,
     ...overrides,
   };
 }
@@ -273,7 +274,7 @@ describe('getAgentPrompt', () => {
     await fs.writeFile(path.join(promptDir, 'PROMPT.md'), promptContent);
 
     const mockManager = {
-      get: vi.fn().mockResolvedValue(makeAgentInfo({ name: agentName })),
+      get: vi.fn().mockResolvedValue(makeAgentInfo({ name: agentName, prompt: null })),
     };
 
     const ctx = createTestContext({
@@ -285,4 +286,42 @@ describe('getAgentPrompt', () => {
 
     expect(result).toEqual({ content: promptContent });
   });
+
+  it('returns prompt from DB when agent.prompt is set (no file needed)', async () => {
+    const dbPromptContent = '# DB Prompt\nThis is persisted in the database';
+    const mockManager = {
+      get: vi.fn().mockResolvedValue(makeAgentInfo({ name: 'test-agent', prompt: dbPromptContent })),
+    };
+
+    // workspaceRoot has no PROMPT.md — but DB value takes precedence
+    const ctx = createTestContext({
+      agentManager: mockManager as any,
+      workspaceRoot: tmpDir,
+    });
+    const caller = createCaller(ctx);
+    const result = await caller.getAgentPrompt({ id: 'agent-1' });
+
+    expect(result).toEqual({ content: dbPromptContent });
+  });
+
+  it('falls back to PROMPT.md when agent.prompt is null in DB', async () => {
+    const agentName = 'test-agent';
+    const promptDir = path.join(tmpDir, '.cw', 'agent-logs', agentName);
+    await fs.mkdir(promptDir, { recursive: true });
+    const fileContent = '# File Prompt\nThis is from the file (legacy)';
+    await fs.writeFile(path.join(promptDir, 'PROMPT.md'), fileContent);
+
+    const mockManager = {
+      get: vi.fn().mockResolvedValue(makeAgentInfo({ name: agentName, prompt: null })),
+    };
+
+    const ctx = createTestContext({
+      agentManager: mockManager as any,
+      workspaceRoot: tmpDir,
+    });
+    const caller = createCaller(ctx);
+    const result = await caller.getAgentPrompt({ id: 'agent-1' });
+
+    expect(result).toEqual({ content: fileContent });
+  });
 });

apps/server/trpc/routers/agent.ts

@@ -342,6 +342,22 @@ export function agentProcedures(publicProcedure: ProcedureBuilder) {
       .query(async ({ ctx, input }) => {
         const agent = await resolveAgent(ctx, { id: input.id });
 
+        const MAX_BYTES = 1024 * 1024; // 1 MB
+
+        function truncateIfNeeded(text: string): string {
+          if (Buffer.byteLength(text, 'utf-8') > MAX_BYTES) {
+            const buf = Buffer.from(text, 'utf-8');
+            return buf.slice(0, MAX_BYTES).toString('utf-8') + '\n\n[truncated — prompt exceeds 1 MB]';
+          }
+          return text;
+        }
+
+        // Prefer DB-persisted prompt (durable even after log file cleanup)
+        if (agent.prompt !== null) {
+          return { content: truncateIfNeeded(agent.prompt) };
+        }
+
+        // Fall back to filesystem for agents spawned before DB persistence was added
         const promptPath = path.join(ctx.workspaceRoot!, '.cw', 'agent-logs', agent.name, 'PROMPT.md');
 
         let raw: string;
@@ -357,13 +373,7 @@ export function agentProcedures(publicProcedure: ProcedureBuilder) {
           });
         }
 
-        const MAX_BYTES = 1024 * 1024; // 1 MB
-        if (Buffer.byteLength(raw, 'utf-8') > MAX_BYTES) {
-          const buf = Buffer.from(raw, 'utf-8');
-          raw = buf.slice(0, MAX_BYTES).toString('utf-8') + '\n\n[truncated — prompt exceeds 1 MB]';
-        }
-
-        return { content: raw };
+        return { content: truncateIfNeeded(raw) };
       }),
   };
 }

docs/database.md

@@ -70,6 +70,7 @@ All adapters use nanoid() for IDs, auto-manage timestamps, and use Drizzle's `.r
 | mode | text enum | 'execute' \| 'discuss' \| 'plan' \| 'detail' \| 'refine' |
 | pid | integer nullable | OS process ID |
 | exitCode | integer nullable | |
+| prompt | text nullable | Full assembled prompt passed to agent at spawn; persisted for durability after log cleanup |
 | outputFilePath | text nullable | |
 | result | text nullable | JSON |
 | pendingQuestions | text nullable | JSON |

docs/server-api.md

@@ -64,7 +64,7 @@ Each procedure uses `require*Repository(ctx)` helpers that throw `TRPCError(INTE
 | getAgentQuestions | query | Pending questions |
 | getAgentOutput | query | Full output from DB log chunks |
 | getAgentInputFiles | query | Files written to agent's `.cw/input/` dir (text only, sorted, 500 KB cap) |
-| getAgentPrompt | query | Content of `.cw/agent-logs/<name>/PROMPT.md` (1 MB cap) |
+| getAgentPrompt | query | Assembled prompt — reads from DB (`agents.prompt`) first; falls back to `.cw/agent-logs/<name>/PROMPT.md` for pre-persistence agents (1 MB cap) |
 | getActiveRefineAgent | query | Active refine agent for initiative |
 | listWaitingAgents | query | Agents waiting for input |
 | onAgentOutput | subscription | Live raw JSONL output stream via EventBus |