qstack-blast-radius

A review method for tracing how a proposed or recent code change could affect parts of a system beyond its immediate diff.

In plain words
What is it for?
Use it to assess compatibility, data formats, generated files, feature flags, lifecycle timing, dependencies, and other consumers before making or approving a change.
Why use it?
It helps reveal downstream breakage that a simple search for callers or a quick diff review may miss.

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

Made for: Claude Code, Codex.

Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 667 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 $0.00061 $0.00667
Opus 5 $0.00030 $0.00333
Sonnet 5 $0.00012 $0.00133
Haiku 4.5 $0.00006 $0.00067

Measured 2d ago against content hash a92e2aa6afbc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

qstack-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 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.

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.

skills/qstack-blast-radius/SKILL.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

QStack blast radius

Find the breakage that a symbol search or diff review would miss. The result is analysis, not permission to edit, commit, push, publish, deploy, or message anyone.

Trace the risk

  1. Resolve the exact change from the user's files, diff, branch, or recent work. Read the surrounding implementation and repository instructions.
  2. State the one critical fact the change is safe because of. Use a second fact only when the safety case truly has two independent hinges.
  3. Follow effects beyond direct callers. Check pinned dependency source and local patches, lifecycle timing, persisted data, wire formats, other languages reading the same bytes, feature flags, generated artifacts, and downstream consumers. Cite real paths and lines. A search with no matches is evidence when its scope is stated.
  4. Separate confirmed risks from cleared risks. For each confirmed risk, name the failure path, likelihood, impact, and cheapest decisive check.

Prove the critical fact

Push each safety fact as far down this ladder as is practical:

  1. A claim only.
  2. Direct source evidence at a real path and line.
  3. A traced bad case that cannot reach the failure.
  4. A script or test that executes the real shipped code and fails loudly when the fact is false.
  5. A reproduction in the running artifact.

Anything below level 4 remains unproven. Say where proof stopped. Do not round a plausible writeup up to a verified conclusion. For analysis-only work, use existing tests or inline, read-only probes. Creating even a temporary proof file requires write authorization. If direct proof is not authorized, keep the fact unproven. Do not mutate production or exercise a destructive path merely to reach a higher proof level.

Report

  • What changed, including behavior the diff does not make obvious.
  • The critical safety fact, its proof level, and the observed evidence.
  • Confirmed risks, ordered by likely cost.
  • Cleared risks and the evidence that cleared them.
  • The cheapest pre-merge check that catches the meaningful failure.

Read the full file on GitHub · 65 lines

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. 2d ago First seen · 65 lines · 61 tokens per session scan A a92e2aa6afbc

Subscribe to this mod's changes

qstack-blast-radius is a skill published in the GitHub repository hani-q/qstack (7 stars, last pushed 5d ago), licensed MIT. It adds 61 tokens to every session and 667 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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