How do I install the Code Blast Radius skill?

Run npx skillmds@latest add asermax/code-blast-radius in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Code Blast Radius safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Code Blast Radius?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Code Blast Radius free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Code Blast Radius?

asermax (@asermax) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Code Blast Radius by asermax — Agent Skill

Name: Code Blast Radius
Author: asermax

File contents

Load mahou:basics first. Then read .mahou/code-blast-radius.md if present.

Code blast radius

Answers one question about a change that already exists: what else does it touch, and does any of it break. This is not a review. It says nothing about whether the change is good and does not hunt for bugs inside the diff.

Step 0: Load what the tracing needs

Load mahou:changeset for the repositories, the base, and the diff. Read the project's CLAUDE.md and the layout it describes, so you know which layers a change can travel through and which other repositories it can reach.

Step 1: Inventory the changed elements

List every element the change alters that something else can depend on:

function and method signatures, including defaults and the types behind them
return types, raised exceptions, and error codes
endpoint paths, request payloads, response shapes, status codes
exported types and shared components
database models and columns
test factories and fixtures, which reach every test in the suite

Skip anything nothing can depend on. A renamed local has no users.

Step 2: Trace each element

Dispatch one mahou:usage-tracer per element, all in a single message so they run together. Give each one the element, the absolute path of the repository it lives in, the base, and the absolute paths of the other repositories in scope.

Spawn them as plain subagents. Do not name them. A named agent becomes a teammate, its report arrives through the message channel, and long reports get truncated there.

Step 3: Merge what comes back

Tracer findings arrive unverified. Drop any that fails to name a user and what that user does differently. Check the rest against the code yourself before they reach the report.

Collapse findings that different tracers raised about the same user, and keep the attribution each tracer gave: introduced by this change, pre-existing, or pre-existing and made reachable more often by this change. A pre-existing problem goes in the report only in the third case.

Step 4: Report

State the base and the diff composition in one line. Then the findings, ordered by reach, with the ones outside the change's own feature first.

Give each one its file and line, what changes for whom, and its attribution. Do not list everything the change touched, and do not pad the report with the users you cleared.

When nothing changes for anyone, say so in one line.

---name: code-blast-radiusdescription: Traces what an already-written change reaches. Fans out a tracer per changed element and reports only the places where behavior changes for someone. Use after code is written, before it is reviewed or merged.---Load mahou:basics first. Then read `.mahou/code-blast-radius.md` if present.# Code blast radiusAnswers one question about a change that already exists: what else does it touch, and does any of it break. This is not a review. It says nothing about whether the change is good and does not hunt for bugs inside the diff.## Step 0: Load what the tracing needsLoad mahou:changeset for the repositories, the base, and the diff. Read the project's `CLAUDE.md` and the layout it describes, so you know which layers a change can travel through and which other repositories it can reach.## Step 1: Inventory the changed elementsList every element the change alters that something else can depend on:- function and method signatures, including defaults and the types behind them- return types, raised exceptions, and error codes- endpoint paths, request payloads, response shapes, status codes- exported types and shared components- database models and columns- test factories and fixtures, which reach every test in the suiteSkip anything nothing can depend on. A renamed local has no users.## Step 2: Trace each elementDispatch one `mahou:usage-tracer` per element, all in a single message so they run together. Give each one the element, the absolute path of the repository it lives in, the base, and the absolute paths of the other repositories in scope.Spawn them as plain subagents. Do not name them. A named agent becomes a teammate, its report arrives through the message channel, and long reports get truncated there.## Step 3: Merge what comes backTracer findings arrive unverified. Drop any that fails to name a user and what that user does differently. Check the rest against the code yourself before they reach the report.Collapse findings that different tracers raised about the same user, and keep the attribution each tracer gave: introduced by this change, pre-existing, or pre-existing and made reachable more often by this change. A pre-existing problem goes in the report only in the third case.## Step 4: ReportState the base and the diff composition in one line. Then the findings, ordered by reach, with the ones outside the change's own feature first.Give each one its file and line, what changes for whom, and its attribution. Do not list everything the change touched, and do not pad the report with the users you cleared.When nothing changes for anyone, say so in one line.

Frequently asked questions

Code Blast Radius