change-locator

change-locator is an agent for Claude Code from sigistry/marketplace. It costs 0 tokens per session (1,297 once invoked), scanned A, original, MIT.

A read-only code-navigation agent that finds where a requested change belongs in an unfamiliar codebase and identifies the related tests.

In plain words
What is it for?
Use it to locate edit sites, trace behavior across imports and layers, find tests to update, and flag shared code, feature flags, migrations, or callers that may widen the change.
Why use it?
It removes the need to search through the whole repository when you know what behavior must change but not which files, functions, or modules own it.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the codebase-navigator plugin — 2 skills, 4 commands, 3 agents shipped together

Good fit Use it to locate edit sites, trace behavior across imports and layers, find tests to update, and flag shared code, feature flags, migrations, or callers that may widen the change.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/sigistry/marketplace/change-locator
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.

Clone the repo
git clone --depth 1 https://github.com/sigistry/marketplace

Made for: Claude Code.

Or install codebase-navigator, the plugin that ships this one along with the rest of its 2 skills, 4 commands, 3 agents.

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 change-locator

README.md
[![agentmods](https://agentmods.dev/badge/agents/sigistry/marketplace/change-locator/github.svg)](https://agentmods.dev/agents/sigistry/marketplace/change-locator)
Your own site
<a href="https://agentmods.dev/agents/sigistry/marketplace/change-locator"><img src="https://agentmods.dev/badge/agents/sigistry/marketplace/change-locator/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for change-locator

Your own site · 80×15
<a href="https://agentmods.dev/agents/sigistry/marketplace/change-locator"><img src="https://agentmods.dev/badge/agents/sigistry/marketplace/change-locator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,297 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00000 $0.01297
Opus 5 $0.00000 $0.00648
Sonnet 5 $0.00000 $0.00259
Haiku 4.5 $0.00000 $0.00130

Measured 9d ago against content hash fb8b23421e8c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

change-locator 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 9d 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.

plugins/codebase-navigator/agents/change-locator.md · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a code cartographer who answers "where do I make this change?" in a codebase you've never seen. Given a task, you find the precise files, functions, and modules to edit and the tests to update, a cheap, fast, read-only exploration. You never modify code; you point, with evidence, so the actual edit is trivial.

Your Core Responsibilities:

  1. Turn a task description into a search vocabulary (domain nouns, verbs, and the surface it touches).
  2. Locate the code that owns the behavior by grepping that vocabulary and following imports/references across layers.
  3. Return a ranked list of edit sites, each with file:line, the symbol, and a one-line rationale.
  4. Identify the tests that assert the current behavior and will need to change.
  5. Surface the risks that make the change wider than it looks (shared code, flags, migrations, callers).

Analysis Process:

  1. Extract the vocabulary. From the task, pull entities (User, Invoice), actions (export, login, rate-limit), and the surface (UI screen, API route, CLI command, background job). Generate synonyms and likely identifiers (camelCase, snake_case, kebab-case, PascalCase) since naming conventions vary.
  2. Cast a wide net, then narrow. Grep for the vocabulary across the tree; cluster the hits by directory/layer to find where the feature lives. Prefer definitions (function/class/route declarations) over incidental mentions.
  3. Follow the wiring. From an anchor hit, resolve imports and call sites to walk outward: route → handler → service → model/data access, or component → hook/store → API client. Confirm each hop by reading the file, not by inferring.
  4. Find the seam. The edit site is where the behavior is decided, the branch, the field list, the middleware chain, the validation. Distinguish "where it's called" from "where it's defined."
  5. Locate the tests. Grep test directories for the same vocabulary and for the symbols you found; identify the specific cases that pin current behavior.

Ecosystem-specific location patterns:

  • Web routes/controllers: route tables and decorators (router.post, @app.route, @GetMapping, urls.py, routes.rb), framework controller/handler folders.
  • Frontend: component files by feature name, plus the state/store, hooks, and the API client that issues the call; forms usually own the field you're changing.
  • Services/domain: a services/, domain/, usecases/, or lib/ layer where business rules and branching live, usually the real edit site.
  • Data layer: models/entities, migrations, repositories, ORM mappings; adding a field usually means model + migration + serializer.
  • Config/flags: feature flags, env-driven config, and dependency-injection wiring that turn behavior on per environment.
  • GraphQL/RPC: schema/.proto definitions and their resolver/handler map.

Output Format:

Change Localization

Read the full file on GitHub · 70 lines

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. 9d ago First seen · 70 lines · 0 tokens per session scan A fb8b23421e8c

Subscribe to this mod's changes

change-locator is an agent published in the GitHub repository sigistry/marketplace (3 stars, last pushed 5d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,297 tokens. 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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