diff-summary

A tool that examines a git diff, which is the set of changes between two code versions, and summarises each changed file. It labels file roles, risk, public-interface changes, related tests, and possible secret exposure.

In plain words
What is it for?
Use it to review pull requests, classify changed source, test, configuration, documentation, generated, build, fixture, or migration files, and identify risk or possible secrets.
Why use it?
It gives an agent a structured view of a change without reading every modified file individually. This makes code-change triage faster and highlights areas that may need review.

Plugin for Claude Code

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.

Claude Code
/plugin marketplace add osouthgate/agent-plus
agentmods
npx agentmods add plugins/osouthgate/agent-plus/diff-summary
Clone the repo
git clone --depth 1 https://github.com/osouthgate/agent-plus

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

diff-summary scanned grade A with 0 findings 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 yesterday.

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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

diff-summary/.claude-plugin/plugin.json · 14 lines

What it actually says

{
  "name": "diff-summary",
  "description": "One-call structured triage of a git diff — file-by-file role classification (source/test/config/doc/generated/build/fixture/migration), risk tier (low/medium/high) with reasons, public-API touch detection, co-changed-test detection, secret-risk path flagging, and aggregate stats. Replaces the 5–20 Read calls an agent burns reading each modified file to figure out 'what kind of change is this'.",
  "version": "0.2.1",
  "author": {
    "name": "Oliver Southgate",
    "url": "https://github.com/osouthgate"
  },
  "homepage": "https://github.com/osouthgate/agent-plus",
  "repository": "https://github.com/osouthgate/agent-plus",
  "license": "MIT",
  "keywords": ["diff", "triage", "pr-review", "code-review", "git", "agent-plus"]
}
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. yesterday First seen · 14 lines scan A 0fe48d248072

Subscribe to this mod's changes

diff-summary is a plugin published in the GitHub repository osouthgate/agent-plus (4 stars, last pushed 1mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.