CodeLookup

A code-change checklist and tool that traces where a function, file, database table, or configuration setting is used. It maps the likely blast radius, meaning the other parts that a change could affect.

In plain words
What is it for?
It is for checking callers, linked systems, contracts, return types, schemas, and signatures before a change. It also guides updates to affected files and integration tests.
Why use it?
Changing code without checking its callers or dependents can leave broken parts of a project. This helps the agent find related work before editing.

Cursor rule for Cursor

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 rules/zethrise/codelookup-skill/codelookup
Clone the repo
git clone --depth 1 https://github.com/ZethRise/CodeLookup-Skill

Made for: Cursor.

Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 258 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 $0.00019 $0.00258
Opus 5 $0.00010 $0.00129
Sonnet 5 $0.00004 $0.00052
Haiku 4.5 $0.00002 $0.00026

Measured 3d ago against content hash 3d4d213971df, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

CodeLookup 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 3d 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.

.cursor/rules/codelookup.mdc · 26 lines

What it actually says

Always check impact before changing codebase. Code changes can break dependent systems. Follow this checklist.

Action Protocol

BEFORE editing, creating, or deleting code (functions, classes, files, variables, tables, config):

  1. Run Dependency Pre-Check:

    • Run workspace local node bin/pre-check.js (or global npx codelookup-check / local npm run check) to scan Git changes, trace dependencies, and map the blast radius.
    • If .codelookup/graph.json does not exist or is outdated, run node bin/generate-graph.js first.
    • Always output the generated Mermaid blast radius flowchart in your response analysis.
  2. Verify Callers:

    • Inspect files identified by the pre-check tool.
    • Trace contract, return type, schema, or signature changes.
  3. Plan Cascade Updates:

    • Ensure all affected callers and linked systems are modified in the same change step. No partial commits.
  4. Run Integration Tests:

    • Run tests covering both the modified file and its dependent files.
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. 3d ago First seen · 26 lines · 19 tokens per session scan A 3d4d213971df

Subscribe to this mod's changes

CodeLookup is a cursor rule published in the GitHub repository ZethRise/CodeLookup-Skill (11 stars, last pushed 1mo ago), licensed MIT. It adds 19 tokens to every session and 258 once invoked, about $0.0001 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 2026-08-30.