Postmortem
Postmortem is a decision-archaeology agent for any GitHub repo.
Core trick
Builds a decision ledger from PR review threads, then answers queries with citations checked by a self-verification pass against the source quotes.
Description
Postmortem is a decision-archaeology agent for any GitHub repo. Point it at a codebase and it reads every PR review, every rejected alternative, every architectural debate — and builds a queryable decision ledger. Ask why the code is the way it is and get a cited answer back in seconds, with every claim traceable to the exact reviewer quote that decided it.
Five interaction modes ship:
1. Ask — natural-language query over the ledger; answers stream with live adaptive-thinking tokens and a self-check pass that verifies every inline citation before the answer is trusted.
2. Impact Ripple — BFS across the decision graph to trace what breaks when an assumption moves.
3. Open Decision — the full rationale + rejected alternatives for any single PR, cited.
4. Ghost Interview — pick a maintainer; Opus speaks in their register using only their own verbatim quotes, with every paraphrase openly disclosed.
5. Conflict Finder — scans the whole ledger for pairs of decisions that quietly contradict each other, ranked by severity.
Shipped with six hero ledgers (hono, zustand, next.js, shadcn-ui, supabase, and the Postmortem repo itself) totaling 155 decisions, 1,876 citations, and 410 rejected alternatives — a queryable public-domain artifact. Also ships as a Claude Code MCP server so all five modes are one claude mcp add postmortem away.
Live: postmortem-mauve.vercel.app · Video: youtu.be/9nbIVa_jnsU · 100% citation-grounded.
README excerpt
<div align="center"> # Postmortem **A decision-archaeology agent for any GitHub repo.** Point it at a codebase — it reads every PR review, every rejected alternative, every architectural debate, and builds a queryable ledger. Ask it anything; get a cited answer back in seconds. [](https://postmortem-mauve.vercel.app/) [](https://postmortem-backend.fly.dev/healthz) [](https://www.anthropic.com/claude/opus) [](./LICENSE) > *Code lives. Intent is a ghost. Postmortem summons it.* ### ▶ Watch the 3-minute demo [](https://youtu.be/9nbIVa_jnsU) *Ingest → ledger → cited answers → Impact Ripple → Conflict Finder → Ghost Interview → Claude Code MCP finale* </div> Shipped in 5 days during [*Built with Opus 4.7: a Claude Code Hackathon*](https://cerebralvalley.ai/events/~/e/built-with-4-7-hackathon) · April 21–26, 2026. The gallery's **▶ Play the Postmortem demo** button replays the same reel live in-browser. --- ## At a glance | | | |---|---| | **Live app** | **[postmortem-mauve.vercel.app](https://postmortem-mauve.vercel.app/)** —