Webhook Transforms

Contract

This skill guarantees:

• External events are transformed into brain pages with proper citations
• Raw payloads are preserved (dead-letter queue if transform fails)
• Entity extraction runs on every transformed event
• Input sanitization: no raw HTML/script passes to brain pages
• Error handling: transform failure logs raw payload, retries once

Phases

1. Define transform. Map event schema to brain page format:

   • Input: raw webhook payload (JSON)
   • Output: brain page content (markdown) + metadata (slug, type, citations)
   • Must sanitize: strip HTML tags, escape script content

2. Register webhook URL. Provide the external service with the webhook endpoint.

3. On event received:

   • Parse payload
   • Run transform function
   • Write brain page via gbrain put
   • Extract entities, run enrichment
   • Add timeline entries to mentioned entities
   • Sync: gbrain sync

4. Error handling:

   • If transform throws: log raw payload to _dead-letter/{timestamp}.md
   • Surface error type to agent
   • Retry once
   • Don't lose events

Example Transforms

SMS Received

Input: {from: "+1555...", body: "Meeting moved to 3pm", timestamp: "..."}
Output: Timeline entry on sender's brain page + task update if action item detected

Meeting Completed

Input: {title: "Weekly sync", attendees: [...], transcript: "...", summary: "..."}
Output: Delegate to meeting-ingestion skill

Social Mention

Input: {platform: "twitter", author: "@handle", text: "...", url: "..."}
Output: Brain page in media/ + entity extraction + backlinks

Output Format

Event transformed and written to brain. Report: "Webhook: {event_type} from {source} → {brain_page_path}"

When it fails

Follow the agent operator protocol for any gbrain error code, exit code, [AGENT] block or notice block. Specific to this skill:

• A transformed write returns write_pending (exit 10): the event is accepted; record the request id and poll it, never replay the event under a new id.
• source_binding_required / insufficient_scope: the webhook's token cannot write that source; tell the user which grant the brain host's operator must add.
• A malformed payload: reject it with the parse error and log it; do not write a partial page.

Anti-Patterns

• Passing raw HTML/script to brain pages (XSS risk)
• Silently dropping events when transform fails (use dead-letter queue)
• Processing webhooks without entity extraction
• Not sanitizing external input before brain writes