17-01-SUMMARY.md

phase	17-write-mode-reliability
plan	1
subsystem	write-mode
tags	write-mode idempotency locking reliability
requires	phase provides 16-write-guardrails write policy enforcement and guardrails
provides	Idempotent write-mode keyed by trigger comment Existing PR discovery to avoid duplicate work on retries/redeliveries Best-effort in-process lock for duplicate concurrent handling
affects	mentions write-mode
tech-stack	added patterns Write idempotency identity derived from (installation, repo, prNumber, commentId, keyword) Deterministic head branch name derived from a short hash Reuse existing PR by head branch discovery
key-files	created modified src/handlers/mention.ts src/handlers/mention.test.ts
key-decisions	Use commentId as the write idempotency anchor (stable across webhook redeliveries) Prefer reusing existing PR over pushing new commits to the same branch
duration	20 min
completed	2026-02-10

Phase 17 Plan 01: Write-Mode Reliability Summary

Made write-mode idempotent and retry-safe by keying write outputs to the triggering comment and reusing an existing PR when the same request is delivered again.

Verification

• bun test

Task Commits

1. dbdbbdf18c feat(write): idempotent write-mode by trigger comment