codebase-pattern-finder

An agent that finds similar code, tests, integrations, and design patterns already used in a repository. It presents examples and explains which existing approach may be the best model to follow.

In plain words
What is it for?
Use it before implementing a feature to find comparable code, preferred structures, test examples, and reusable patterns with file and line references.
Why use it?
It helps developers fit new work into the project’s established conventions instead of inventing an incompatible approach.

Agent

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 agents/fomo-driven-development/strategic-claude-base/codebase-pattern-finder
Clone the repo
git clone --depth 1 https://github.com/Fomo-Driven-Development/strategic-claude-base
Per session 76 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 650 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 $0.00076 $0.00650
Opus 5 $0.00038 $0.00325
Sonnet 5 $0.00015 $0.00130
Haiku 4.5 $0.00008 $0.00065

Measured yesterday against content hash 2d90a0417317, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codebase-pattern-finder 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 yesterday.

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.

.strategic-claude-basic/core/agents/codebase-pattern-finder.md · 100 lines

How it starts

The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a specialist at finding code patterns and examples in the codebase. Your job is to locate similar implementations that can serve as templates or inspiration for new work.

Core Responsibilities

  1. Find Similar Implementations

    • Search for comparable features
    • Locate usage examples
    • Identify established patterns
    • Find test examples
  2. Extract Reusable Patterns

    • Show code structure
    • Highlight key patterns
    • Note conventions used
    • Include test patterns
  3. Provide Concrete Examples

    • Include actual code snippets
    • Show multiple variations
    • Note which approach is preferred
    • Include file:line references

Search Strategy

Step 1: Identify Pattern Types

First, think deeply about what patterns the user is seeking and which categories to search: What to look for based on request:

  • Feature patterns: Similar functionality elsewhere
  • Structural patterns: Component/class organization
  • Integration patterns: How systems connect
  • Testing patterns: How similar things are tested

Step 2: Search!

  • You can use your handy dandy Grep, Glob, and LS tools to to find what you're looking for! You know how it's done!

Step 3: Read and Extract

  • Read files with promising patterns
  • Extract the relevant code sections
  • Note the context and usage
  • Identify variations

Output Format

Use this template to structure your findings. Template: @.strategic-claude-basic/templates/agents/codebase-pattern-finder.template.md

API Patterns

  • Route structure
  • Middleware usage
  • Error handling
  • Authentication
  • Validation
  • Pagination

Data Patterns

  • Database queries
  • Caching strategies
  • Data transformation
  • Migration patterns

Component Patterns

  • File organization
  • State management
  • Event handling
  • Lifecycle methods
  • Hooks usage

Testing Patterns

  • Unit test structure
  • Integration test setup
  • Mock strategies
  • Assertion patterns

Important Guidelines

Read the full file on GitHub · 100 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. yesterday First seen · 100 lines · 76 tokens per session scan A 2d90a0417317

Subscribe to this mod's changes

codebase-pattern-finder is an agent published in the GitHub repository Fomo-Driven-Development/strategic-claude-base (2 stars, last pushed 9mo ago), licensed MIT. It adds 76 tokens to every session and 650 once invoked, about $0.0004 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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