Interesting artifacts and learnings must be written back to this document.

Automatically create Discord threads on messages in channels with [autothread] in their topic/description. Uses high-frequency polling (every 2-5 seconds) since Val Town cannot use Discord WebSockets. Thread creation is immediate upon detecting new messages. AI uses recent message history (last ~4 messages or 5 minutes) purely for contextual thread naming.

Key constraints:

• Val Town environment (Deno, SQLite, cron triggers)
• No WebSocket support → high-frequency polling via vt cron (2-5 second interval)
• valtown-watch handles auto-sync
• Use vt tail for log observation during development

Timing model:

• Val Town cron triggers every 1 minute (minimum allowed)
• Internal polling loop runs every 2-5 seconds within each cron execution (~55 seconds of polling per run)
• New messages are threaded immediately upon detection
• Recent message context (last ~4 messages or 5 minutes) gathered only for AI summarization
• No intentional delay before threading

Idempotency is critical because:

• Multiple poll iterations occur within a single cron run
• Cron runs may overlap if execution takes longer than expected
• Same message may be seen across multiple poll iterations
• DB-based deduplication with optimistic insert is the primary safeguard

---

Extend the existing DiscordService with new endpoints required for auto-threading.

• Add Discord API methods to backend/discord.ts
• Add 429 rate limit handling with retry logic

• Existing backend/discord.ts infrastructure

Task	Acceptance Criteria
Add listGuildChannels() method	Returns array of {id, name, type, topic?} from GET /guilds/{guild_id}/channels
Add getMessages(channelId, options?) method	Returns messages from GET /channels/{channel_id}/messages with {after?: string, limit?: number} options, limit clamped to 1-100
Add startThreadFromMessage(channelId, messageId, name) method	Creates thread via POST /channels/{channel_id}/messages/{message_id}/threads
Add 429 rate limit handling in request()	On 429 response: parse retry_after, wait, retry (max 2 retries)
Add TypeScript types for Discord message/channel objects	Types match Discord API v10 response shapes

Test scenarios:

1. listGuildChannels() returns channels with correct shape including topic field
2. getMessages() respects after snowflake parameter and limit
3. startThreadFromMessage() creates thread and returns thread ID
4. Rate limit handling: mock 429 response triggers retry after delay
5. NoopDiscordService implements all new methods with appropriate logging

Pass/fail criteria:

• All methods return expected types
• Rate limit retry logic executes correctly (verified via logs in test environment)
• NoopDiscordService mirrors RealDiscordService interface

Test organization:

• Unit tests: backend/__tests__/discord.test.ts
• Integration tests (manual via vt tail): backend/__tests__/discord.integration.ts

---

Create tracking tables and a dry-run cron job that identifies candidate messages without creating threads.

• New SQLite tables for channel tracking and message deduplication
• New cron file backend/autothread.cron.ts
• Environment variables for configuration

• Gate 0 complete

Task	Acceptance Criteria
Create autothread_channels table	Stores channel_id, topic, last_seen_at, last_message_id
Create autothread_processed table	Stores channel_id, message_id, thread_id, status, error, processed_at with PK on (channel_id, message_id)
Create autothread.cron.ts entry point	Exports default async function; runs internal loop polling every ~5 seconds for ~55 seconds
Implement channel discovery logic	Fetches guild channels, filters by [autothread] in topic
Implement message scanning logic	Fetches last ~20 messages, identifies any not yet processed
Track last-processed message per channel	Store last_message_id in autothread_channels for efficient polling
Implement dry-run logging	Logs "would create thread" for each candidate, inserts status='dry_run'
Add AUTOTHREAD_DRY_RUN env var	When true, skips actual thread creation
Add AUTOTHREAD_CHANNEL_ALLOWLIST env var	Comma-separated channel IDs; only process listed channels when set
Add per-run caps	MAX_CHANNELS_PER_RUN=3, MAX_THREADS_PER_RUN=5

Test scenarios:

1. Channel discovery correctly filters by [autothread] in topic (case-insensitive)
2. Channel allowlist restricts processing to listed channels only
3. New messages (not in autothread_processed) are identified immediately
4. Already-processed messages (existing in autothread_processed) are skipped
5. last_message_id tracking enables efficient incremental polling
6. Per-run caps prevent runaway processing
7. Dry-run mode logs candidates but does not call startThreadFromMessage
8. Idempotency: Same message seen in consecutive poll iterations is not reprocessed
9. Internal polling loop runs ~11 iterations (55s / 5s) per cron invocation

Pass/fail criteria:

• Cron runs without error (verified via vt tail)
• Correct messages identified in logs
• Database rows created with status='dry_run'
• No actual threads created when AUTOTHREAD_DRY_RUN=true

Test organization:

• Unit tests: backend/__tests__/autothread.test.ts (snowflake math, filtering logic)
• Integration tests: backend/__tests__/autothread.integration.ts (end-to-end dry run)
• Manual verification: vt tail during live dry-run

---

Actually create threads on identified messages using deterministic naming.

• Implement thread creation logic
• Deterministic thread naming from message content
• Idempotent processing via optimistic DB insert

• Gate 1 complete

Task	Acceptance Criteria
Implement deterministic thread naming	First 60 chars of message content, sanitized; fallback to Discussion from {author} @ {HH:MM}
Implement optimistic insert pattern	Insert status='processing' before API call; skip on PK conflict (critical for idempotency across poll iterations and overlapping cron runs)
Call startThreadFromMessage()	Creates thread with deterministic name
Update database on success	Set status='created', store thread_id
Update database on failure	Set status='error', store error message
Ignore bot messages	Skip messages where author.bot === true
Ignore very short messages	Skip messages with content < 10 characters

Test scenarios:

1. Thread created with correct name (first 60 chars of message)
2. Fallback naming used when message content is unsuitable
3. Bot messages are skipped
4. Short messages (< 10 chars) are skipped
5. PK conflict in DB correctly prevents duplicate thread creation
6. API error results in status='error' row, not crash
7. Rate limits handled gracefully with retry

Pass/fail criteria:

• Threads appear in Discord with expected names
• Database accurately reflects thread creation status
• No duplicate threads created for same message
• Errors logged and captured in DB, cron continues

Test organization:

• Unit tests: backend/__tests__/autothread.test.ts (naming logic, filtering)
• Integration tests: Run cron on test channel, verify threads created
• Manual verification: Check Discord test channel

---

Use OpenAI to generate contextual thread names and summaries from recent messages.

• Gather message context (5 before, 2 after target message)
• Call OpenAI for thread name + summary
• Post summary as first message in created thread
• Graceful fallback to deterministic naming on AI failure

• Gate 2 complete
• OPENAI_API_KEY environment variable

Task	Acceptance Criteria
Add AUTOTHREAD_ENABLE_AI env var	When false or unset, use deterministic naming
Implement context gathering	Collect last ~4 messages before target (or up to 5 min of history) for context
Create AI prompt for thread naming	Returns thread_name (≤100 chars) and summary (2-5 bullets)
Call OpenAI API	Use gpt-4o-mini, limit tokens appropriately
Create thread with AI name	Use AI-generated name, fallback to deterministic on failure
Post summary in thread	Send AI summary as first message in new thread
Implement token/cost limits	Limit context to ~1000 tokens input
Fallback on AI error	Log error, proceed with deterministic name, skip summary

Test scenarios:

1. AI generates appropriate thread name from context
2. Thread name respects 100 character Discord limit
3. Summary is posted as first message in thread
4. AI failure results in fallback to deterministic name (not crash)
5. Context gathering correctly selects nearby messages
6. AUTOTHREAD_ENABLE_AI=false skips AI entirely

Pass/fail criteria:

• AI-named threads are contextually relevant
• Summary provides useful context for thread participants
• No failures when AI is unavailable/errors
• Token usage stays within limits

Test organization:

• Unit tests: backend/__tests__/autothread-ai.test.ts (context gathering, prompt construction)
• Integration tests: Run cron with AI enabled on test channel
• Manual verification: Review AI-generated names and summaries in Discord

---

Production-ready safeguards and operational improvements.

• Per-channel cooldowns
• Ignore rules for commands and special messages
• Monitoring and alerting
• Documentation

• Gate 3 complete

Task	Acceptance Criteria
Add per-channel cooldown	No more than 3 threads created per channel per 10 minutes
Add command prefix ignore list	Skip messages starting with !, /, .
Add content filter	Skip messages that are only emoji, links, or mentions
Add autothread_stats table	Track threads created per channel per day for monitoring
Implement health check endpoint	/api/autothread/health returns last run status, errors
Add README documentation	Document env vars, behavior, and operational considerations
Add channel-specific config	[autothread:quiet] disables AI summary posting

Test scenarios:

1. Per-channel cooldown prevents burst thread creation
2. Command messages (starting with !, /, .) are skipped
3. Emoji-only and link-only messages are skipped
4. Stats table accurately tracks daily thread counts
5. Health endpoint returns meaningful status
6. [autothread:quiet] mode creates threads without summary messages

Pass/fail criteria:

• System operates safely under burst message conditions
• Operational visibility via health endpoint
• Documentation is accurate and complete

Test organization:

• Unit tests: backend/__tests__/autothread-hardening.test.ts
• Load tests: Simulate burst of messages, verify caps/cooldowns
• Manual verification: Review stats and health endpoint

---

Variable	Gate	Required	Description
DISCORD_BOT_TOKEN	0	Yes	Bot authentication
DISCORD_GUILD_ID	0	Yes	Guild to monitor
AUTOTHREAD_DRY_RUN	1	No	Skip actual thread creation when true
AUTOTHREAD_CHANNEL_ALLOWLIST	1	No	Comma-separated channel IDs
AUTOTHREAD_ENABLE_AI	3	No	Enable AI naming when true
OPENAI_API_KEY	3	For AI	OpenAI API key (Val Town std lib)

---

Endpoint	Purpose	Gate
GET /guilds/{guild_id}/channels	List channels with topics	0
GET /channels/{channel_id}/messages	Fetch recent messages	0
POST /channels/{channel_id}/messages/{message_id}/threads	Create thread	0
POST /channels/{thread_id}/messages	Post summary (existing)	3

---

Internal loop pattern (Val Town cron minimum is 1 minute):

export default async function() {
  const POLL_INTERVAL_MS = 5000;
  const RUN_DURATION_MS = 55000; // Leave 5s buffer before next cron
  const startTime = Date.now();
  
  while (Date.now() - startTime < RUN_DURATION_MS) {
    await pollAndProcessMessages();
    await new Promise(r => setTimeout(r, POLL_INTERVAL_MS));
  }
}

Per-iteration logic:

1. Fetch last ~20 messages from each [autothread] channel
2. Compare against autothread_processed table to find new messages
3. Use last_message_id in autothread_channels for efficient after parameter
4. Thread new messages immediately (optimistic insert prevents duplicates)
5. Gather last ~4 messages before target for AI context (if AI enabled)

Snowflake math (for after parameter optimization):

const DISCORD_EPOCH = 1420070400000n; // 2015-01-01T00:00:00.000Z
const snowflake = ((BigInt(Date.now()) - DISCORD_EPOCH) << 22n).toString();

---

Record discoveries, gotchas, and useful patterns here during implementation.

• Discord topic field is the channel description
• Thread starter messages have thread property when thread exists
• Rate limits: process channels sequentially to avoid 429s
• Gate 0: getMessages() returns newest-first; Gate 1 must sort by ID for chronological processing
• Gate 0: Discord limits getMessages to 100 messages max per call
• Gate 0: 429 response retry_after may be missing/malformed - added defensive parsing
• Gate 1: Use insert-first (optimistic insert) for idempotency, not SELECT-then-INSERT (race window)
• Gate 1: Only advance last_message_id cursor past messages fully handled to avoid message loss on caps
• Gate 1: Always upsert channel state even when no new messages, so channels get registered
• Gate 2: Pagination must go backwards (newest→oldest) to avoid missing messages when >limit arrive between polls
• Gate 2: Use same sanitizeContent() for both validation and thread naming to ensure consistency
• Gate 2: Dry-run inserts status='dry_run' rows - switching to live requires clearing/bumping tables
• Gate 3: AI context must use full allMessages (incl. before cursor), not just newMessages
• Gate 3: JSON parsing must handle code fences and extra text from LLM responses
• Gate 3: Summary must be capped at 2000 chars (Discord message limit)
• Gate 3: Thread name must be sanitized same as deterministic (sanitizeContent + 100 char limit)
• Gate 4: [autothread:quiet] tag regex must match variants like [autothread], [autothread:quiet]
• Gate 4: Link-only filter must handle multiple links and Discord <https://...> format
• Gate 4: Health endpoint needs autothread_runs table to track actual cron run status
• Gate 4: Cooldown uses sliding window count from PROCESSED_TABLE (threads in last 10 min)

Implemented a comprehensive debug console for testing in Val Town's deploy-to-prod environment.

• Execution modes: plan (no writes), dry_run (DB only), live (full)
• Namespaces: sandbox (isolated testing) vs prod (real data)
• Manual triggers: Run autothread on-demand via HTTP endpoints
• Component testing: Test Discord API, AI naming, gate evaluation in isolation
• State inspection: View and manipulate database state
• Event logging: Queryable run history with detailed events

• backend/autothread/ - Refactored module structure
  • types.ts - Type definitions and config defaults
  • store.ts - Database operations with namespace support
  • logic.ts - Core processing logic
  • runner.ts - High-level runner
  • README.md - Documentation
• backend/autothread-debug.http.ts - Debug HTTP endpoints

• POST /api/autothread/debug/run - Trigger debug run
• GET /api/autothread/debug/state - Inspect DB state
• GET /api/autothread/debug/runs - List run history
• POST /api/autothread/debug/eval-message - Test gate evaluation
• POST /api/autothread/debug/generate-ai-name - Test AI naming

See backend/autothread/README.md for full documentation.

The debug console is currently on the auto-threading branch. To test it:

1. Merge to main: Use the Val Town web UI at https://www.val.town/x/colel/rust-nyc-talk-submissions/branch/auto-threading/code/ to merge into main
2. After merge, endpoints will be available at:
   • https://rustnyc-talks.val.run/api/autothread/debug/
   • https://rustnyc-talks.val.run/api/autothread/health

Set these in Val Town project settings:

• ADMIN_TOKEN - Bearer token for debug endpoints
• ENABLE_TEST_API=true - Enable debug endpoints
• DISCORD_BOT_TOKEN - Discord bot authentication
• DISCORD_GUILD_ID - Guild to monitor
• OPENAI_API_KEY - For AI naming (optional)

Fixed export in backend/autothread-debug.http.ts:

• Changed export default app.fetch to export default app
• app.route() in Hono expects a Hono app instance, not a fetch function