pr-explain

A plain-language guide to a pull request, the proposed set of code changes submitted for review. It explains the change, walks through the whole difference, lists tests, scores the evidence, and records commands and their output.

In plain words
What is it for?
It creates a reader-facing explainer covering the reason for the change, every part of the diff, all tests, proof of behavior, and the commands used to verify it.
Why use it?
It gives the code owner a complete explanation of what changed and how well the result was checked, rather than only a short summary.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/a1f/agent-templates/pr-explain
Any agent
npx skills add a1f/agent-templates --skill pr-explain
Clone the repo
git clone --depth 1 https://github.com/a1f/agent-templates

Made for: Claude Code, Codex.

Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,251 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00087 $0.07251
Opus 5 $0.00044 $0.03625
Sonnet 5 $0.00017 $0.01450
Haiku 4.5 $0.00009 $0.00725

Measured 2d ago against content hash 55f12fa5dfec, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

pr-explain scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **Safe commands only**: test runners, linters, builds, read-only CLI and `curl` against a
skills/pr-explain/SKILL.md · 437 lines

How it starts

The opening of the file, as written. The whole thing — 437 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PR Explain

Write the page you would produce pair-programming with the person who owns this repo: you at the keyboard, walking them through the change you just made. They want to keep a clear mental model of code that agents typed. They are not hunting for bugs — a reviewer does that. They want to understand the whole change, not a sampler of it.

Three rules run through the whole page:

  • Plain words. The english rule governs every word on the page — it loads each session, so you already have it. Say it the way you would to a smart friend who has not seen the code. If a code word is the only word that fits (hash, symlink, CI), say what it does in plain words right after — once. Talk to the reader: "you", "your".
  • The whole diff. Every change in the PR is either shown and explained or named in a roll-up line. A reader who finishes the walkthrough has seen the change — never two excerpts from a hundred-line diff.
  • Proof is scored, not asserted. Output on the page is output you captured. Every piece of it sits on the ladder below, carrying its points. A reader sees at a glance whether this change was watched working or merely compiled. "All tests passed" is the weakest sentence on the page, never the proof.

Arguments

Form Meaning
(blank) The open PR for the current branch
#N or N PR number in the target repo
a PR URL That PR
--confirmed "<what you saw>" Fills the ladder's top row — you ran this change yourself. Quoted verbatim, dated today. Combines with any form above

Runtime resolution

  • Template: ~/.claude/at/templates/pr-explain-page.html — design tokens plus the .bottomline, .goals, .tree, .hunk-head, .testlist, .wit, .score, .rung, .short-proof, .gate-chip, .no-proof, .ba-label, and .cmd classes the chapters use. Missing? Still ship: build a single-file HTML page with inline CSS that follows the chapter contract. Visual polish degrades; the contract does not.
  • Vale config: ~/.claude/at/templates/pr-explain.vale.ini, staged with the template. It names the write-good / proselint / Google packages the mechanical prose gate runs. Missing, or vale not installed → the gate degrades to the wc + banned-word checks.
  • Page file: write the filled page to the session scratch directory (never the target repo) as pr-<owner>-<repo>-<number>.html, owner/repo parsed from the PR's url.
  • Target repo: the git repo of the working directory; run every gh/git command there.

Read the full file on GitHub · 437 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 437 lines · 0 tokens per session scan A 55f12fa5dfec

Subscribe to this mod's changes

pr-explain is a skill published in the GitHub repository a1f/agent-templates (2 stars, last pushed 2d ago), licensed MIT. It adds 87 tokens to every session and 7,251 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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