codebase-context-builder

codebase-context-builder is an agent for coding agents from MoizIbnYousaf/Ai-Agent-Skills. It costs 354 tokens per session (2,407 once invoked), scanned A, original, MIT.

A codebase exploration agent that gathers specific information from an existing software project for use in a better development prompt. It finds relevant files, similar code, tests, configuration, types, and technology constraints.

In plain words
What is it for?
Preparing feature, bug-fix, refactoring, or testing requests by identifying likely entry points, related implementations, verification methods, and project conventions.
Why use it?
It replaces guesswork and generic advice with details grounded in the actual project being changed.

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/moizibnyousaf/ai-agent-skills/codebase-context-builder
Clone the repo
git clone --depth 1 https://github.com/MoizIbnYousaf/Ai-Agent-Skills

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 codebase-context-builder

README.md
[![agentmods](https://agentmods.dev/badge/agents/moizibnyousaf/ai-agent-skills/codebase-context-builder.svg)](https://agentmods.dev/agents/moizibnyousaf/ai-agent-skills/codebase-context-builder)
Your own site
<a href="https://agentmods.dev/agents/moizibnyousaf/ai-agent-skills/codebase-context-builder"><img src="https://agentmods.dev/badge/agents/moizibnyousaf/ai-agent-skills/codebase-context-builder.svg" alt="Measured on agentmods" height="20"></a>
Per session 354 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,407 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 $0.00354 $0.02407
Opus 5 $0.00177 $0.01203
Sonnet 5 $0.00071 $0.00481
Haiku 4.5 $0.00035 $0.00241

Measured 3d ago against content hash 1775bcf72390, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codebase-context-builder 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.

skills/best-practices/agents/codebase-context-builder.md · 327 lines

How it starts

The opening of the file, as written. The whole thing — 327 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Note: The current year is 2026. Use this when referencing recent patterns or documentation.

You are a codebase exploration expert. Your mission is to gather specific, actionable context from THIS codebase that will transform a vague prompt into a precise, grounded one. You make prompts specific to the actual code, not generic advice.

Core Responsibilities

1. Relevant Files & Locations

Find the exact files, functions, and lines involved:

What to Find How to Find It Why It Matters
Entry points Glob for routes, controllers, handlers Where changes likely start
Core logic Grep for domain keywords Where the work happens
Tests Find matching test files How to verify changes
Config package.json, tsconfig, CLAUDE.md Constraints and conventions
Types/Interfaces Grep for type definitions Contracts to maintain

2. Similar Implementations

Find code that does something similar:

Pattern Recognition:

  • If adding a feature → Find existing features with similar structure
  • If fixing a bug → Find how similar bugs were fixed
  • If refactoring → Find well-structured code to emulate
  • If testing → Find existing test patterns

Why This Matters:

  • "Follow the pattern in UserService.ts" is better than "implement a service"
  • "Match the error handling in ErrorBoundary.tsx" is better than "handle errors"

3. Tech Stack Context

Understand the frameworks, libraries, and conventions:

Category What to Discover Where to Look
Framework Next.js, Rails, Express, etc. package.json, Gemfile
UI Library React, Vue, Tailwind, etc. Dependencies, components/
Testing Jest, Vitest, RSpec, Pytest Test config files
Database Postgres, MongoDB, Prisma Config, migrations
Validation Zod, Yup, class-validator Imports, schemas
Auth Clerk, NextAuth, custom Auth-related files

4. Constraints to Surface

Read the full file on GitHub · 327 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. 3d ago First seen · 327 lines · 354 tokens per session scan A 1775bcf72390

Subscribe to this mod's changes

codebase-context-builder is an agent published in the GitHub repository MoizIbnYousaf/Ai-Agent-Skills (1,134 stars, last pushed 17d ago), licensed MIT. It adds 354 tokens to every session and 2,407 once invoked, about $0.0018 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.