FathomFathom · pull request review for the AI era
AI writes the code. You review the system.
Watch a real pull request become the system it changes, then what it changed.
Preserve navigation during chat
Problem. Asking mid-walk stopped navigation.
Move. Touch the route only after a new one succeeds.
Price. Every user shares one daily budget.
Should a route edit mid-walk still stop navigation?
Is one 1,000-a-day budget sized for every user?
A pull request: 32 files of code.
Why
Let AI read every line. You judge the design.
- Reads the diff and the repo
- Maps the parts and how they talk
- Replays the request, before and after
- Scores trade-offs, finds the risks
- Is this the right design?
- Is the trade-off worth it?
- Can we undo it?
- Ship it?
The pages
Seven pages. No walls of text.
Vital signs.
Kind, risk, reach, reversibility. The PR in three sentences.
Behaviour, as a diff.
+ added, − gone, ~ changed. Red where it broke.
The system, as a blueprint.
Processes, parts, every boundary crossed.
Every decision, scored.
What it chose, and what it gave up.
A one-way door?
Hazards by likelihood and impact. Unguarded ones filled.
Questions worth asking.
Ask Fathom to dig, or ask the author.
The lines, when you want them.
Chaptered by purpose. One review, under your name.
Under the hood
Three readings. Under a minute.
Your Claude Code reads the PR three ways at once, with a read-only look at the repo.
Your GitHub
Posts only when you submit.
Your Claude plan
Read-only. No MCP, no hooks.
No servers
Readings stay on your Mac.
Principle
It never tells you to ship. It shows you what you’re shipping.
No verdicts.No generic advice.No robot approvals.
- Download and open Fathom.
- GitHub CLI, then Sign In in the app.
brew install gh
- Claude Code, signed in once.
curl -fsSL https://claude.ai/install.sh | bash
- Open a pull request.