# Tier 2 Implementation Plan

**Date**: 2026-02-07
**Features**: Inbound Webhooks, Dockerfile, Heartbeat, Vector Memory Search
**Status**: Planning

---

## 1. Inbound Webhooks

**Complexity**: Medium

### Overview

HTTP endpoint (`POST /webhooks/:name`) that triggers agent processing, following the same pattern as `CronScheduler`: implements `ChannelAdapter`, produces `InboundMessage`, routes responses to a configured output channel.

### Config Schema Additions

Add to `src/config/schema.ts`:

```typescript
const webhookSchema = z.object({
  name: z.string().min(1, 'Webhook name is required'),
  /** Optional per-webhook HMAC secret for payload signature verification. */
  secret: z.string().optional(),
  /** Message template — use {{body}} for raw body, {{json.fieldName}} for JSON fields. */
  message: z.string().default('{{body}}'),
  output: z.object({
    channel: z.string().min(1),
    peer: z.string().min(1),
  }),
  enabled: z.boolean().default(true),
});
```

Extend `automationSchema`:

```typescript
const automationSchema = z.object({
  cron: z.array(cronJobSchema).default([]),
  webhooks: z.array(webhookSchema).default([]),
}).default({});
```

Add type export:

```typescript
export type WebhookConfig = z.infer<typeof webhookSchema>;
```

### Files to Create

| File | Purpose |
|------|---------|
| `src/automation/webhooks.ts` | `WebhookHandler` class implementing `ChannelAdapter` |
| `src/automation/webhooks.test.ts` | Unit tests |

### Files to Modify

| File | Change |
|------|--------|
| `src/config/schema.ts` | Add `webhookSchema`, extend `automationSchema`, add type export |
| `src/automation/index.ts` | Export `WebhookHandler` |
| `src/gateway/server.ts` | Route `POST /webhooks/:name` to the `WebhookHandler` before static/404 |
| `src/daemon/index.ts` | Instantiate `WebhookHandler`, register with `ChannelRegistry`, wire to gateway |

### Key Class: `WebhookHandler`

```typescript
// src/automation/webhooks.ts

import { createHmac, timingSafeEqual } from 'crypto';
import type { IncomingMessage, ServerResponse } from 'http';
import type { ChannelAdapter, ChannelStatus, InboundMessage, OutboundMessage } from '../channels/types.js';
import type { WebhookConfig } from '../config/schema.js';

/** Minimal interface for the parts of ChannelRegistry we need. */
interface ChannelLookup {
  get(name: string): { send(peerId: string, message: OutboundMessage): Promise<void> } | undefined;
}

export class WebhookHandler implements ChannelAdapter {
  readonly name = 'webhook';
  private _status: ChannelStatus = 'disconnected';
  private messageHandler?: (msg: InboundMessage) => void;
  private webhooks: Map<string, WebhookConfig> = new Map();

  constructor(
    private readonly webhookConfigs: WebhookConfig[],
    private readonly channelLookup: ChannelLookup,
  ) {
    for (const wh of webhookConfigs) {
      this.webhooks.set(wh.name, wh);
    }
  }

  // ChannelAdapter interface methods...
  get status(): ChannelStatus { return this._status; }
  async connect(): Promise<void> { this._status = 'connected'; }
  async disconnect(): Promise<void> { this._status = 'disconnected'; }
  onMessage(handler: (msg: InboundMessage) => void): void { this.messageHandler = handler; }

  async send(peerId: string, message: OutboundMessage): Promise<void> {
    // Route to output channel (same pattern as CronScheduler.send)
    const webhook = this.webhooks.get(peerId);
    if (!webhook) return;
    const outputAdapter = this.channelLookup.get(webhook.output.channel);
    if (!outputAdapter) return;
    await outputAdapter.send(webhook.output.peer, message);
  }

  /**
   * Handle incoming HTTP request. Called by the gateway HTTP handler.
   * Returns true if the request was handled (webhook found), false otherwise.
   */
  async handleRequest(webhookName: string, req: IncomingMessage, res: ServerResponse): Promise<boolean> {
    const webhook = this.webhooks.get(webhookName);
    if (!webhook || !webhook.enabled) {
      return false; // Not found, let gateway return 404
    }

    // Read body
    const body = await readBody(req);

    // Verify HMAC signature if secret configured
    if (webhook.secret) {
      const signature = req.headers['x-webhook-signature'] as string | undefined;
      if (!verifyHmac(body, webhook.secret, signature)) {
        res.writeHead(401, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ error: 'Invalid signature' }));
        return true;
      }
    }

    // Build message text from template
    const messageText = renderTemplate(webhook.message, body);

    // Produce InboundMessage
    const msg: InboundMessage = {
      id: `webhook-${webhookName}-${Date.now()}`,
      channel: 'webhook',
      senderId: webhookName,
      senderName: `webhook:${webhookName}`,
      text: messageText,
      timestamp: Date.now(),
      metadata: { webhookName, contentType: req.headers['content-type'] },
    };

    this.messageHandler?.(msg);

    res.writeHead(202, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify({ accepted: true, id: msg.id }));
    return true;
  }

  getWebhookNames(): string[] {
    return Array.from(this.webhooks.keys());
  }
}
```

### Integration in Gateway HTTP Handler

In `GatewayServer.handleHttpRequest()`, add route matching **before** the static file serving:

```typescript
// Check for webhook routes: POST /webhooks/:name
if (req.method === 'POST' && req.url) {
  const match = req.url.match(/^\/webhooks\/([a-zA-Z0-9_-]+)/);
  if (match && this.webhookHandler) {
    const handled = await this.webhookHandler.handleRequest(match[1], req, res);
    if (handled) return;
  }
}
```

The `webhookHandler` reference is passed into `GatewayServerConfig` as an optional field, similar to how `channelRegistry` is passed.

### Integration in Daemon Startup

In `src/daemon/index.ts`, after the cron scheduler block (~line 812-817):

```typescript
// Register webhook handler (if any webhooks configured)
let webhookHandler: WebhookHandler | undefined;
if (config.automation.webhooks.length > 0) {
  webhookHandler = new WebhookHandler(config.automation.webhooks, channelRegistry);
  channelRegistry.register(webhookHandler);
  console.log(`Registered ${config.automation.webhooks.length} webhook(s)`);
}
```

Then pass `webhookHandler` to the `GatewayServer` constructor.

### HMAC Verification

Standard approach: `X-Webhook-Signature: sha256=<hex>` header, verified via `crypto.createHmac('sha256', secret).update(body).digest('hex')` with timing-safe comparison.

Also support gateway token auth as an alternative (already handled by the gateway auth middleware for HTTP).

### Template Rendering

Simple template engine for the `message` field:
- `{{body}}` — raw request body string
- `{{json.fieldName}}` — extracted JSON field (dot notation for nested)
- Default: `{{body}}` if no template specified

### Test Plan

`src/automation/webhooks.test.ts`:
- Implements ChannelAdapter interface (name, status)
- `handleRequest()` produces InboundMessage with correct fields
- HMAC verification rejects invalid signatures
- HMAC verification passes valid signatures
- Returns false for unknown webhook names
- Returns false for disabled webhooks
- `send()` routes to output channel (same as cron test pattern)
- Template rendering with `{{body}}` and `{{json.field}}`
- `getWebhookNames()` lists all webhook names

### Config Example

```yaml
automation:
  webhooks:
    - name: github-push
      secret: "whsec_..."
      message: "GitHub push to {{json.repository.full_name}}: {{json.head_commit.message}}"
      output:
        channel: telegram
        peer: "123456"
    - name: alertmanager
      message: "Alert: {{json.alerts.0.annotations.summary}}"
      output:
        channel: telegram
        peer: "123456"
```

---

## 2. Dockerfile

**Complexity**: Simple

### Overview

Multi-stage Docker build for the Flynn daemon. No TypeScript source code changes required — this is purely build/deployment infrastructure.

### Files to Create

| File | Purpose |
|------|---------|
| `Dockerfile` | Multi-stage build |
| `.dockerignore` | Exclude dev artifacts |
| `docker-compose.yml` | Example deployment with volumes |

### Dockerfile Design

```dockerfile
# ── Stage 1: Build ──────────────────────────────────────────────
FROM node:22-alpine AS builder

# Install pnpm
RUN corepack enable && corepack prepare pnpm@latest --activate

WORKDIR /app

# Install dependencies first (layer caching)
COPY package.json pnpm-lock.yaml ./
RUN pnpm install --frozen-lockfile

# Copy source and build
COPY tsconfig.json ./
COPY src/ src/

# better-sqlite3 needs build tools for native compilation
RUN apk add --no-cache python3 make g++ && \
    pnpm build

# ── Stage 2: Runtime ────────────────────────────────────────────
FROM node:22-alpine AS runtime

RUN corepack enable && corepack prepare pnpm@latest --activate

WORKDIR /app

# Copy package files and install production deps only
COPY package.json pnpm-lock.yaml ./
RUN apk add --no-cache python3 make g++ && \
    pnpm install --frozen-lockfile --prod && \
    apk del python3 make g++

# Copy compiled output from builder
COPY --from=builder /app/dist dist/

# Copy gateway UI assets (if they exist)
COPY --from=builder /app/src/gateway/ui dist/gateway/ui/

# Copy prompt templates and bundled skills
COPY prompts/ prompts/
COPY skills/ skills/

# Create data directories
RUN mkdir -p /data/memory /data/sessions /config

# Runtime config
ENV NODE_ENV=production
ENV FLYNN_CONFIG=/config/config.yaml
ENV FLYNN_DATA_DIR=/data

EXPOSE 18800

# Health check
HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
  CMD wget -qO- http://localhost:18800/ || exit 1

ENTRYPOINT ["node", "dist/cli/index.js"]
CMD ["start"]
```

### Key Considerations

**better-sqlite3 native deps**: This is the trickiest part. `better-sqlite3` requires native compilation. Options:
1. Install build tools (`python3`, `make`, `g++`) in the runtime stage, compile, then remove — this is the safest approach and keeps the image functional.
2. Use `--build-from-source` flag and carry the built `.node` binary from the builder stage. This requires matching the Node.js version and Alpine version exactly between stages (which we do since both use `node:22-alpine`).
3. Alternatively, use `better-sqlite3`'s prebuilt binaries if they ship for Alpine/musl — check at build time.

**Recommended approach**: Option 2 — copy `node_modules` from builder stage since both stages use identical base image:

```dockerfile
# In runtime stage, instead of separate pnpm install:
COPY --from=builder /app/node_modules node_modules/
```

This eliminates the need for build tools in the runtime image entirely and produces a smaller image.

### .dockerignore

```
node_modules/
dist/
.git/
.gitignore
*.log
.env
.env.*
.worktrees/
docs/
src/**/*.test.ts
vitest.config.*
eslint.config.*
tsconfig.json
*.md
!README.md
```

### docker-compose.yml

```yaml
version: '3.8'
services:
  flynn:
    build: .
    image: flynn:latest
    container_name: flynn
    restart: unless-stopped
    ports:
      - "18800:18800"
    volumes:
      - ./config.yaml:/config/config.yaml:ro
      - flynn-data:/data
      - flynn-memory:/data/memory
    environment:
      - FLYNN_CONFIG=/config/config.yaml
      - ANTHROPIC_API_KEY=${ANTHROPIC_API_KEY}
      # Add other provider keys as needed
    healthcheck:
      test: ["CMD", "wget", "-qO-", "http://localhost:18800/"]
      interval: 30s
      timeout: 5s
      retries: 3

volumes:
  flynn-data:
  flynn-memory:
```

### Daemon Changes for Docker

The daemon currently defaults data dir to `~/.local/share/flynn`. For Docker, we need to respect an environment variable override. Check if `src/daemon/index.ts` already handles this.

Looking at line 525: `const dataDir = resolve(homedir(), '.local/share/flynn');`

**Modification needed** in `src/daemon/index.ts`:

```typescript
// Support FLYNN_DATA_DIR env var for Docker deployments
const dataDir = process.env.FLYNN_DATA_DIR ?? resolve(homedir(), '.local/share/flynn');
```

Similarly, config loading in `src/config/loader.ts` should respect `FLYNN_CONFIG` env var if not already.

### Files to Modify

| File | Change |
|------|--------|
| `src/daemon/index.ts` | Support `FLYNN_DATA_DIR` environment variable |
| `src/config/loader.ts` | Support `FLYNN_CONFIG` environment variable (verify) |

### Test Plan

No unit tests needed (Docker build is tested by building). Integration test:
- `docker build -t flynn:test .`
- `docker run --rm flynn:test --help` (verify CLI works)
- `docker compose up -d` with test config (verify startup)

---

## 3. Heartbeat

**Complexity**: Medium

### Overview

Periodic self-check system that validates daemon health and optionally notifies a configured channel on failure. Fits naturally as an extension to the `src/automation/` module, alongside cron.

### Config Schema Additions

Add to `src/config/schema.ts`:

```typescript
const heartbeatCheckSchema = z.enum([
  'gateway',           // Is the HTTP/WS server responsive?
  'model',             // Can we reach the default model provider?
  'channels',          // Are all channel adapters connected?
  'memory',            // Is the memory store readable/writable?
  'disk',              // Is disk space above threshold?
]);

const heartbeatSchema = z.object({
  enabled: z.boolean().default(false),
  /** Check interval (e.g. '60s', '5m', '1h'). Default: '5m'. */
  interval: z.string().default('5m'),
  /** Which checks to run. Default: all. */
  checks: z.array(heartbeatCheckSchema).default(['gateway', 'model', 'channels', 'memory', 'disk']),
  /** Optional notification on failure. */
  notify: z.object({
    channel: z.string().min(1),
    peer: z.string().min(1),
  }).optional(),
  /** Number of consecutive failures before notifying. Default: 2. */
  failure_threshold: z.number().min(1).max(10).default(2),
  /** Disk space warning threshold in MB. Default: 100. */
  disk_threshold_mb: z.number().min(10).default(100),
}).default({});
```

Extend `automationSchema`:

```typescript
const automationSchema = z.object({
  cron: z.array(cronJobSchema).default([]),
  webhooks: z.array(webhookSchema).default([]),
  heartbeat: heartbeatSchema,
}).default({});
```

Add type export:

```typescript
export type HeartbeatConfig = z.infer<typeof heartbeatSchema>;
```

### Files to Create

| File | Purpose |
|------|---------|
| `src/automation/heartbeat.ts` | `HeartbeatMonitor` class |
| `src/automation/heartbeat.test.ts` | Unit tests |

### Files to Modify

| File | Change |
|------|--------|
| `src/config/schema.ts` | Add `heartbeatSchema`, extend `automationSchema`, add type export |
| `src/automation/index.ts` | Export `HeartbeatMonitor` |
| `src/daemon/index.ts` | Instantiate `HeartbeatMonitor`, register shutdown handler |

### Key Class: `HeartbeatMonitor`

```typescript
// src/automation/heartbeat.ts

import { statfsSync } from 'fs';
import type { HeartbeatConfig } from '../config/schema.js';
import type { ChannelAdapter, ChannelStatus, OutboundMessage } from '../channels/types.js';
import type { ModelRouter } from '../models/router.js';

export interface HeartbeatCheckResult {
  name: string;
  healthy: boolean;
  message: string;
  durationMs: number;
}

export interface HeartbeatResult {
  timestamp: number;
  healthy: boolean;
  checks: HeartbeatCheckResult[];
}

interface HeartbeatDeps {
  config: HeartbeatConfig;
  /** Get the gateway HTTP server for health probing. */
  getGatewayPort?: () => number;
  /** Model router for provider health check. */
  modelRouter?: ModelRouter;
  /** Channel registry for adapter status checks. */
  getChannels?: () => Array<{ name: string; status: ChannelStatus }>;
  /** Memory store dir for read/write check. */
  memoryDir?: string;
  /** Data dir for disk space check. */
  dataDir?: string;
  /** Send notification to a channel. */
  notify?: (channel: string, peer: string, message: OutboundMessage) => Promise<void>;
}

export class HeartbeatMonitor {
  private timer?: ReturnType<typeof setInterval>;
  private consecutiveFailures = 0;
  private lastResult?: HeartbeatResult;

  constructor(private readonly deps: HeartbeatDeps) {}

  start(): void {
    if (!this.deps.config.enabled) return;
    const intervalMs = parseInterval(this.deps.config.interval);
    this.timer = setInterval(() => this.runChecks(), intervalMs);
    // Run first check after a short delay (let services finish starting)
    setTimeout(() => this.runChecks(), 5000);
  }

  stop(): void {
    if (this.timer) {
      clearInterval(this.timer);
      this.timer = undefined;
    }
  }

  /** Run all configured checks and optionally notify on failure. */
  async runChecks(): Promise<HeartbeatResult> {
    const checks: HeartbeatCheckResult[] = [];
    const enabledChecks = this.deps.config.checks;

    for (const checkName of enabledChecks) {
      const start = Date.now();
      try {
        const result = await this.runSingleCheck(checkName);
        checks.push({ ...result, durationMs: Date.now() - start });
      } catch (error) {
        checks.push({
          name: checkName,
          healthy: false,
          message: error instanceof Error ? error.message : String(error),
          durationMs: Date.now() - start,
        });
      }
    }

    const healthy = checks.every(c => c.healthy);
    const result: HeartbeatResult = { timestamp: Date.now(), healthy, checks };
    this.lastResult = result;

    if (!healthy) {
      this.consecutiveFailures++;
      if (this.consecutiveFailures >= this.deps.config.failure_threshold) {
        await this.sendNotification(result);
      }
    } else {
      // Reset on recovery
      if (this.consecutiveFailures >= this.deps.config.failure_threshold) {
        await this.sendRecoveryNotification(result);
      }
      this.consecutiveFailures = 0;
    }

    return result;
  }

  getLastResult(): HeartbeatResult | undefined {
    return this.lastResult;
  }

  private async runSingleCheck(name: string): Promise<Omit<HeartbeatCheckResult, 'durationMs'>> {
    switch (name) {
      case 'gateway':   return this.checkGateway();
      case 'model':     return this.checkModel();
      case 'channels':  return this.checkChannels();
      case 'memory':    return this.checkMemory();
      case 'disk':      return this.checkDisk();
      default:          return { name, healthy: false, message: `Unknown check: ${name}` };
    }
  }

  // Individual check implementations...
}
```

### Individual Check Implementations

1. **Gateway check**: HTTP GET to `http://localhost:<port>/` — expects non-error response.
2. **Model check**: Call `modelRouter.healthCheck()` or attempt a minimal completion with max_tokens=1. Note: `ModelRouter` doesn't currently have a health check method, so we'd add a lightweight one that just verifies the API key/connection. Alternatively, use a simpler approach: verify the model client can be instantiated without errors, or do a `models.list()` API call for providers that support it.
3. **Channels check**: Iterate registered channels, verify all have `status === 'connected'`.
4. **Memory check**: Attempt `store.read('global')` and verify no exceptions.
5. **Disk check**: Use `statfsSync()` on the data directory, calculate free space in MB, compare to threshold.

### Notification Format

```
⚠️ Flynn Heartbeat Failure

Failed checks:
- gateway: Connection refused on port 18800
- model: API key invalid (401)

Consecutive failures: 3/2 (threshold)
```

And on recovery:

```
✅ Flynn Heartbeat Recovery

All checks passing after 3 consecutive failures.
```

### Integration in Daemon Startup

In `src/daemon/index.ts`, after all services are started (after `gateway.start()`):

```typescript
// Initialize heartbeat monitor (if enabled)
let heartbeatMonitor: HeartbeatMonitor | undefined;
if (config.automation.heartbeat?.enabled) {
  heartbeatMonitor = new HeartbeatMonitor({
    config: config.automation.heartbeat,
    getGatewayPort: () => config.server.port,
    modelRouter,
    getChannels: () => channelRegistry.list().map(a => ({ name: a.name, status: a.status })),
    memoryDir: memoryDir,
    dataDir,
    notify: config.automation.heartbeat.notify
      ? async (channel, peer, message) => {
          const adapter = channelRegistry.get(channel);
          if (adapter) await adapter.send(peer, message);
        }
      : undefined,
  });
  heartbeatMonitor.start();
  console.log(`Heartbeat monitor started (interval: ${config.automation.heartbeat.interval})`);

  lifecycle.onShutdown(async () => {
    heartbeatMonitor!.stop();
    console.log('Heartbeat monitor stopped');
  });
}
```

### Interval Parsing

Reuse or create a simple parser (similar to `parseDuration` in `src/session/index.ts`):

```typescript
function parseInterval(str: string): number {
  const match = str.match(/^(\d+)(s|m|h)$/);
  if (!match) return 300_000; // default 5 minutes
  const [, value, unit] = match;
  const multipliers: Record<string, number> = { s: 1000, m: 60_000, h: 3_600_000 };
  return parseInt(value) * multipliers[unit];
}
```

### Exposing via Gateway (Optional Enhancement)

Add a `system.heartbeat` handler to the gateway WS handlers that returns `heartbeatMonitor.getLastResult()`. This lets the web UI or CLI display health status. This is a nice-to-have and can be done as a follow-up.

### Test Plan

`src/automation/heartbeat.test.ts`:
- `start()` does nothing when `enabled: false`
- `runChecks()` runs all configured checks
- `runChecks()` returns healthy=true when all checks pass
- `runChecks()` returns healthy=false when any check fails
- Notification sent after `failure_threshold` consecutive failures
- Recovery notification sent when checks pass after failures
- `stop()` clears the timer
- `getLastResult()` returns most recent result
- Individual check tests:
  - `checkChannels()` detects disconnected adapters
  - `checkDisk()` detects low disk space
  - `checkMemory()` handles missing memory dir
- `parseInterval()` correctly parses '60s', '5m', '1h'

### Config Example

```yaml
automation:
  heartbeat:
    enabled: true
    interval: "5m"
    checks: [gateway, model, channels, memory, disk]
    notify:
      channel: telegram
      peer: "123456"
    failure_threshold: 2
    disk_threshold_mb: 100
```

---

## 4. Vector Memory Search

**Complexity**: Complex

### Overview

Add embedding-based semantic search to the existing `MemoryStore`, enabling hybrid search (vector similarity + keyword). Provider-agnostic embedding generation with graceful fallback to keyword-only search when embeddings are unavailable.

### Architecture Decision: Storage Backend

**Options considered**:
1. **SQLite with manual vector math** — Store embeddings as BLOBs in the existing `better-sqlite3` database, compute cosine similarity in JS. Simple, no new deps.
2. **SQLite with sqlite-vec extension** — Native vector similarity in SQL. Requires native extension compilation, complicates Docker build.
3. **Separate HNSW index (hnswlib-node)** — Purpose-built ANN index. Fast for large collections but adds a native dep.
4. **In-memory float arrays** — Store embeddings as JSON files alongside markdown, load into memory, compute similarity in JS.

**Recommendation**: Option 1 (SQLite with manual vector math). Rationale:
- `better-sqlite3` is already a dependency
- Memory collections are small enough (hundreds to low thousands of chunks) that brute-force cosine similarity in JS is fast enough (<10ms for 1000 vectors)
- No new native dependencies
- Embeddings stored in existing data directory pattern
- Clean upgrade path to sqlite-vec if performance becomes an issue

### Config Schema Additions

Extend `memorySchema` in `src/config/schema.ts`:

```typescript
const embeddingProviderSchema = z.enum(['openai', 'gemini', 'ollama', 'llamacpp']);

const embeddingSchema = z.object({
  enabled: z.boolean().default(false),
  provider: embeddingProviderSchema.default('openai'),
  model: z.string().default('text-embedding-3-small'),
  /** Provider endpoint (required for ollama/llamacpp). */
  endpoint: z.string().optional(),
  /** API key (required for openai/gemini). */
  api_key: z.string().optional(),
  /** Embedding vector dimensions. Auto-detected from model if not set. */
  dimensions: z.number().optional(),
  /** Max tokens per chunk for embedding. Default: 512. */
  chunk_size: z.number().min(64).max(8192).default(512),
  /** Overlap between chunks in tokens. Default: 50. */
  chunk_overlap: z.number().min(0).max(1024).default(50),
  /** Number of top results to return from vector search. Default: 5. */
  top_k: z.number().min(1).max(50).default(5),
  /** Weight for vector results vs keyword results in hybrid scoring (0.0 = keyword only, 1.0 = vector only). Default: 0.7. */
  hybrid_weight: z.number().min(0).max(1).default(0.7),
}).default({});

const memorySchema = z.object({
  enabled: z.boolean().default(true),
  dir: z.string().optional(),
  auto_extract: z.boolean().default(true),
  max_context_tokens: z.number().min(100).max(10000).default(2000),
  embedding: embeddingSchema,
}).default({});
```

Add type exports:

```typescript
export type EmbeddingConfig = z.infer<typeof embeddingSchema>;
```

### Files to Create

| File | Purpose |
|------|---------|
| `src/memory/embeddings.ts` | `EmbeddingProvider` interface + provider implementations |
| `src/memory/embeddings.test.ts` | Unit tests for embedding providers |
| `src/memory/vector-store.ts` | `VectorStore` class — SQLite-backed vector storage |
| `src/memory/vector-store.test.ts` | Unit tests for vector store |
| `src/memory/chunker.ts` | Text chunking utility |
| `src/memory/chunker.test.ts` | Unit tests for chunker |
| `src/memory/hybrid-search.ts` | `HybridSearch` class — combines vector + keyword |
| `src/memory/hybrid-search.test.ts` | Unit tests for hybrid search |

### Files to Modify

| File | Change |
|------|--------|
| `src/config/schema.ts` | Add `embeddingSchema`, extend `memorySchema`, add type export |
| `src/memory/store.ts` | Add `searchHybrid()` method, accept optional `VectorStore` in constructor |
| `src/memory/index.ts` | Export new modules |
| `src/tools/builtin/memory-search.ts` | Use `searchHybrid()` when available, fall back to `search()` |
| `src/daemon/index.ts` | Initialize `EmbeddingProvider`, `VectorStore`, wire into `MemoryStore` |

### Key Interfaces and Classes

#### EmbeddingProvider

```typescript
// src/memory/embeddings.ts

export interface EmbeddingProvider {
  /** Generate embeddings for one or more text chunks. */
  embed(texts: string[]): Promise<number[][]>;
  /** Embedding vector dimensions. */
  readonly dimensions: number;
}

export class OpenAIEmbeddingProvider implements EmbeddingProvider {
  // Uses openai SDK (already a dep) with embeddings.create()
  readonly dimensions: number;
  constructor(config: { apiKey?: string; model: string; dimensions?: number }) { ... }
  async embed(texts: string[]): Promise<number[][]> { ... }
}

export class GeminiEmbeddingProvider implements EmbeddingProvider {
  // Uses @google/generative-ai SDK (already a dep) with embedContent()
  readonly dimensions: number;
  constructor(config: { apiKey?: string; model: string }) { ... }
  async embed(texts: string[]): Promise<number[][]> { ... }
}

export class OllamaEmbeddingProvider implements EmbeddingProvider {
  // Uses ollama SDK (already a dep) with embeddings()
  readonly dimensions: number;
  constructor(config: { host?: string; model: string }) { ... }
  async embed(texts: string[]): Promise<number[][]> { ... }
}

export class LlamaCppEmbeddingProvider implements EmbeddingProvider {
  // HTTP POST to /embedding endpoint
  readonly dimensions: number;
  constructor(config: { endpoint: string; model?: string }) { ... }
  async embed(texts: string[]): Promise<number[][]> { ... }
}

export function createEmbeddingProvider(config: EmbeddingConfig): EmbeddingProvider { ... }
```

#### Text Chunker

```typescript
// src/memory/chunker.ts

export interface Chunk {
  /** The text content of this chunk. */
  text: string;
  /** Source namespace. */
  namespace: string;
  /** Starting line number in the source file (1-based). */
  startLine: number;
  /** Ending line number in the source file (1-based). */
  endLine: number;
}

/**
 * Split memory content into overlapping chunks suitable for embedding.
 *
 * Strategy: split on paragraph boundaries (double newline), then merge
 * small paragraphs to reach target chunk size, with configurable overlap.
 */
export function chunkText(
  content: string,
  namespace: string,
  options: { chunkSize: number; chunkOverlap: number },
): Chunk[] { ... }
```

#### VectorStore

```typescript
// src/memory/vector-store.ts

import Database from 'better-sqlite3';

export interface VectorSearchResult {
  namespace: string;
  chunkText: string;
  startLine: number;
  endLine: number;
  similarity: number;
}

export class VectorStore {
  private db: Database.Database;

  constructor(dbPath: string) {
    this.db = new Database(dbPath);
    this.initSchema();
  }

  private initSchema(): void {
    this.db.exec(`
      CREATE TABLE IF NOT EXISTS embeddings (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        namespace TEXT NOT NULL,
        chunk_text TEXT NOT NULL,
        start_line INTEGER NOT NULL,
        end_line INTEGER NOT NULL,
        embedding BLOB NOT NULL,
        created_at INTEGER NOT NULL DEFAULT (unixepoch()),
        content_hash TEXT NOT NULL
      );
      CREATE INDEX IF NOT EXISTS idx_embeddings_namespace ON embeddings(namespace);
      CREATE INDEX IF NOT EXISTS idx_embeddings_hash ON embeddings(content_hash);
    `);
  }

  /** Store embedding vectors for a set of chunks. */
  upsertChunks(chunks: Array<{ namespace: string; text: string; startLine: number; endLine: number; embedding: number[]; contentHash: string }>): void { ... }

  /** Delete all embeddings for a namespace (for re-indexing). */
  deleteNamespace(namespace: string): void { ... }

  /** Check if a namespace+hash combination already exists (skip re-embedding). */
  hasContentHash(namespace: string, hash: string): boolean { ... }

  /**
   * Search for similar vectors using cosine similarity.
   * Computed in JS — fine for <10k vectors.
   */
  search(queryEmbedding: number[], topK: number): VectorSearchResult[] {
    const allRows = this.db.prepare('SELECT * FROM embeddings').all();
    // Compute cosine similarity for each, sort, take topK
    ...
  }

  close(): void {
    this.db.close();
  }
}
```

The embedding is stored as a BLOB (Float32Array buffer). Cosine similarity:

```typescript
function cosineSimilarity(a: number[], b: number[]): number {
  let dotProduct = 0;
  let normA = 0;
  let normB = 0;
  for (let i = 0; i < a.length; i++) {
    dotProduct += a[i] * b[i];
    normA += a[i] * a[i];
    normB += b[i] * b[i];
  }
  return dotProduct / (Math.sqrt(normA) * Math.sqrt(normB));
}
```

#### HybridSearch

```typescript
// src/memory/hybrid-search.ts

import type { SearchResult } from './store.js';
import type { VectorSearchResult, VectorStore } from './vector-store.js';
import type { EmbeddingProvider } from './embeddings.js';
import type { MemoryStore } from './store.js';

export interface HybridSearchResult {
  namespace: string;
  content: string;
  context: string;
  line: number;
  score: number;
  source: 'keyword' | 'vector' | 'both';
}

export class HybridSearch {
  constructor(
    private readonly memoryStore: MemoryStore,
    private readonly vectorStore: VectorStore,
    private readonly embeddingProvider: EmbeddingProvider,
    private readonly hybridWeight: number = 0.7,
  ) {}

  /**
   * Search using both keyword and vector similarity, merge and rank results.
   *
   * Scoring: final_score = (hybrid_weight * vector_score) + ((1 - hybrid_weight) * keyword_score)
   * Keyword score: 1.0 for exact match (normalized by result count)
   * Vector score: cosine similarity (0.0 - 1.0)
   */
  async search(query: string, topK: number = 5): Promise<HybridSearchResult[]> {
    // Run both searches in parallel
    const [keywordResults, vectorResults] = await Promise.all([
      Promise.resolve(this.memoryStore.search(query)),
      this.vectorSearch(query, topK * 2), // fetch more for merge
    ]);

    return this.mergeResults(keywordResults, vectorResults, topK);
  }

  private async vectorSearch(query: string, topK: number): Promise<VectorSearchResult[]> {
    const [queryEmbedding] = await this.embeddingProvider.embed([query]);
    return this.vectorStore.search(queryEmbedding, topK);
  }

  private mergeResults(
    keyword: SearchResult[],
    vector: VectorSearchResult[],
    topK: number,
  ): HybridSearchResult[] {
    // Deduplicate by namespace+line, compute hybrid score, sort, take topK
    ...
  }
}
```

### Indexing Pipeline

When does indexing happen? Two approaches:

1. **On write**: When `MemoryStore.write()` is called, also chunk + embed + store. This keeps the index always up to date but adds latency to writes.
2. **Background indexer**: A separate timer that scans for unindexed content (via content hash comparison) and indexes it periodically.

**Recommendation**: Background indexer with write-triggered hint. On `MemoryStore.write()`, mark the namespace as "dirty". The background indexer (runs every 30s or so) processes only dirty namespaces. This keeps writes fast while ensuring the index stays reasonably fresh.

```typescript
// Addition to MemoryStore:
private dirtyNamespaces: Set<string> = new Set();

write(namespace: string, content: string, mode: 'append' | 'replace'): void {
  // ... existing write logic ...
  this.dirtyNamespaces.add(namespace);
}

getDirtyNamespaces(): string[] {
  const ns = Array.from(this.dirtyNamespaces);
  this.dirtyNamespaces.clear();
  return ns;
}
```

Indexer runs in daemon:

```typescript
// In daemon startup, after memory store init:
if (memoryStore && config.memory.embedding.enabled) {
  const embeddingProvider = createEmbeddingProvider(config.memory.embedding);
  const vectorStore = new VectorStore(resolve(dataDir, 'vectors.db'));
  const hybridSearch = new HybridSearch(memoryStore, vectorStore, embeddingProvider, config.memory.embedding.hybrid_weight);

  // Background indexer
  const indexInterval = setInterval(async () => {
    const dirty = memoryStore.getDirtyNamespaces();
    for (const ns of dirty) {
      const content = memoryStore.read(ns);
      const contentHash = createHash('md5').update(content).digest('hex');
      if (vectorStore.hasContentHash(ns, contentHash)) continue;

      const chunks = chunkText(content, ns, {
        chunkSize: config.memory.embedding.chunk_size,
        chunkOverlap: config.memory.embedding.chunk_overlap,
      });
      const embeddings = await embeddingProvider.embed(chunks.map(c => c.text));
      vectorStore.upsertChunks(chunks.map((c, i) => ({
        namespace: c.namespace,
        text: c.text,
        startLine: c.startLine,
        endLine: c.endLine,
        embedding: embeddings[i],
        contentHash,
      })));
    }
  }, 30_000);

  lifecycle.onShutdown(async () => {
    clearInterval(indexInterval);
    vectorStore.close();
  });
}
```

### Integration with memory.search Tool

Modify `src/tools/builtin/memory-search.ts` to accept an optional `HybridSearch` instance:

```typescript
export function createMemorySearchTool(store: MemoryStore, hybridSearch?: HybridSearch): Tool {
  return {
    name: 'memory.search',
    description: 'Search across all memory files for a keyword or phrase. Uses semantic search when available, with keyword fallback.',
    inputSchema: {
      type: 'object',
      properties: {
        query: {
          type: 'string',
          description: 'The search query (supports semantic meaning when embeddings are enabled)',
        },
      },
      required: ['query'],
    },
    execute: async (rawArgs: unknown): Promise<ToolResult> => {
      const args = rawArgs as { query: string };

      try {
        if (hybridSearch) {
          const results = await hybridSearch.search(args.query);
          // Format hybrid results...
        } else {
          // Existing keyword-only path (unchanged)
          const results = store.search(args.query);
          // ...existing formatting...
        }
      } catch (error) {
        // On vector search failure, fall back to keyword
        const results = store.search(args.query);
        // ...format with note about fallback...
      }
    },
  };
}
```

Also update `createMemoryTools()` in `src/tools/builtin/index.ts` to accept the optional `HybridSearch`:

```typescript
export function createMemoryTools(store: MemoryStore, hybridSearch?: HybridSearch): Tool[] {
  return [
    createMemoryReadTool(store),
    createMemoryWriteTool(store),
    createMemorySearchTool(store, hybridSearch),
  ];
}
```

### Graceful Fallback Chain

1. If `embedding.enabled: false` (default) — pure keyword search, no embedding deps loaded
2. If `embedding.enabled: true` but provider unreachable — log warning, fall back to keyword search
3. If embedding succeeds but vector DB corrupted — catch error, fall back to keyword search
4. If embedding succeeds — hybrid search with configurable weight

### Test Plan

**`src/memory/chunker.test.ts`**:
- Splits text into chunks of configured size
- Respects paragraph boundaries
- Generates correct overlap between chunks
- Handles empty content
- Preserves line number tracking
- Single paragraph smaller than chunk size returns one chunk

**`src/memory/embeddings.test.ts`**:
- `createEmbeddingProvider()` creates correct provider for each type
- OpenAI provider calls correct API endpoint (mocked)
- Ollama provider calls correct endpoint (mocked)
- Provider returns correct dimensionality
- Handles API errors gracefully

**`src/memory/vector-store.test.ts`**:
- Creates SQLite database with correct schema
- `upsertChunks()` stores and retrieves embeddings
- `search()` returns results sorted by similarity
- `deleteNamespace()` removes all embeddings for a namespace
- `hasContentHash()` detects existing content
- `close()` cleans up database connection
- Cosine similarity computation is correct

**`src/memory/hybrid-search.test.ts`**:
- Returns keyword results when vector search unavailable
- Merges keyword and vector results with correct weighting
- Deduplicates results from both sources
- Respects `topK` limit
- Handles empty results from either source
- `source` field correctly indicates 'keyword', 'vector', or 'both'

### Config Example

```yaml
memory:
  enabled: true
  auto_extract: true
  max_context_tokens: 2000
  embedding:
    enabled: true
    provider: openai
    model: text-embedding-3-small
    api_key: "${OPENAI_API_KEY}"
    chunk_size: 512
    chunk_overlap: 50
    top_k: 5
    hybrid_weight: 0.7
```

---

## Implementation Order

Recommended sequence (dependencies and risk):

| Order | Feature | Rationale |
|-------|---------|-----------|
| 1 | **Dockerfile** | No code changes, unblocks deployment testing for all other features |
| 2 | **Inbound Webhooks** | Clean pattern (mirrors cron), moderate scope, high utility |
| 3 | **Heartbeat** | Depends on running services for meaningful checks, benefits from Docker for testing |
| 4 | **Vector Memory Search** | Most complex, most files, most risk — do last when other features are stable |

### Estimated Effort

| Feature | New Files | Modified Files | Estimated Lines | Complexity |
|---------|-----------|----------------|-----------------|------------|
| Inbound Webhooks | 2 | 4 | ~300 | Medium |
| Dockerfile | 3 | 1-2 | ~100 | Simple |
| Heartbeat | 2 | 3 | ~350 | Medium |
| Vector Memory Search | 8 | 5 | ~800 | Complex |
| **Total** | **15** | **12-13** | **~1550** | |

---

## Cross-Cutting Concerns

### Config Schema Validation

All new schema additions follow the existing pattern:
- Use `.default({})` for optional sections so the config is valid without them
- Export `z.infer<>` type aliases
- Existing tests in `src/config/schema.test.ts` should still pass (no breaking changes)

### Daemon Startup Order

New services slot into the existing startup sequence:

1. Memory store (existing)
2. **Vector store + embedding provider** (new, after memory store)
3. Session store (existing)
4. Tool registry (existing)
5. **Memory tools with hybrid search** (modified)
6. Gateway server (existing)
7. Channel registry (existing)
8. **Webhook handler** (new, registered with channel registry)
9. Cron scheduler (existing)
10. Start all channels (existing)
11. Start gateway (existing)
12. **Heartbeat monitor** (new, after all services started)

### Shutdown Order (LIFO)

Added to lifecycle in reverse:
1. Heartbeat monitor stop
2. Gateway stop (existing)
3. Channel adapters stop (existing, includes webhook handler)
4. Vector store close
5. Process manager stop (existing)
6. Session store close (existing)