blast-radius

blast-radius is a skill for Codex from lootlog/monorepo. It costs 57 tokens per session (338 once invoked), scanned A, original, MIT.

A review method for finding what a code change could affect beyond the lines edited. It follows callers, packages, data contracts, database fields, queues, generated files, and other connected systems.

In plain words
What is it for?
Use it for risky reviews, shared-package changes, migrations, generated contracts, message queues, WebSockets, and requests to assess what might break.
Why use it?
A change can break code that is not visible in its diff. This method identifies indirect risks and checks the key assumptions with focused evidence.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: installed under .agents/ (shared by several agents).

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/lootlog/monorepo/blast-radius
Any agent
npx skills add lootlog/monorepo --skill blast-radius
Clone the repo
git clone --depth 1 https://github.com/lootlog/monorepo

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for blast-radius

README.md
[![agentmods](https://agentmods.dev/badge/skills/lootlog/monorepo/blast-radius.svg)](https://agentmods.dev/skills/lootlog/monorepo/blast-radius)
Your own site
<a href="https://agentmods.dev/skills/lootlog/monorepo/blast-radius"><img src="https://agentmods.dev/badge/skills/lootlog/monorepo/blast-radius.svg" alt="Measured on agentmods" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 338 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 5.1 $0.00057 $0.00338
Opus 5 $0.00028 $0.00169
Sonnet 5 $0.00011 $0.00068
Haiku 4.5 $0.00006 $0.00034

Measured 6d ago against content hash 8a6c757a181e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

blast-radius 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 6d 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.

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.

.agents/skills/blast-radius/SKILL.md · 31 lines

What it actually says

Blast radius

Find the indirect failure modes before a change ships.

Workflow

  1. Read the diff, affected symbols, package boundaries, schemas, generated artifacts, and relevant tests.
  2. If .codegraph/ exists, use CodeGraph before text search to trace callers, callees, and package relationships.
  3. State the one or two facts that make the change safe. Do not hide assumptions inside a long risk list.
  4. Trace where symbol search stops: OpenAPI contracts, database columns, serialized events, Redis keys, queue payloads, generated clients, environment variables, and consumers in other workspaces.
  5. Classify each meaningful risk by likelihood, impact, and the cheapest check that would expose it.
  6. Prove the key safety fact with the narrowest real check available: a focused test, a script against production code, an existing running application, or direct inspection of a generated artifact. Do not start an application in this repository.
  7. Run adjacent validation in proportion to the risk.

Report

Return:

  • what behavior changed;
  • the key safety fact and the strongest evidence reached;
  • confirmed risks with concrete paths and checks;
  • risks investigated and cleared;
  • the smallest pre-merge verification still needed.

Mark an assumption as unproven when it cannot be checked cheaply. A plausible explanation is not proof.

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 6d ago First seen · 31 lines · 57 tokens per session scan A 8a6c757a181e

Subscribe to this mod's changes

blast-radius is a skill published in the GitHub repository lootlog/monorepo (10 stars, last pushed yesterday), licensed MIT. It adds 57 tokens to every session and 338 once invoked, about $0.0003 per session on Opus 5. 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.

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