What is contextception CLAUDE.md?

Project instructions for Contextception, a Go tool that analyzes a codebase to determine which code an agent should understand before making a change. It is available as a command-line program and an MCP server, a service that exposes tools to AI agents.

Use it to index and analyze Python, TypeScript or JavaScript, Go, Java, Rust, and C# repositories and produce context bundles for safe code changes.

It helps agents focus on relevant code and reduce the risk of changing a system without understanding its dependencies.

How kehoej/contextception configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to kehoej/contextception. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/kehoej/contextception/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/kehoej/contextception

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/kehoej/contextception/claude-md/github.svg)](https://agentmods.dev/instructions/kehoej/contextception/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/kehoej/contextception/claude-md"><img src="https://agentmods.dev/badge/instructions/kehoej/contextception/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/kehoej/contextception/claude-md"><img src="https://agentmods.dev/badge/instructions/kehoej/contextception/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,007 This file is loaded in full into every session.

When invoked 1,007 The same file — it is already loaded in full.

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.

Model	Per session	Once invoked
Fable 5.1	$0.01007	$0.01007
Opus 5.5	$0.00403	$0.00403
Sonnet 5.5	$0.00201	$0.00201
Haiku 4.5	$0.00101	$0.00101

Measured 2mo ago against content hash f86606fa2271, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

contextception CLAUDE.md 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 2mo 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.

CLAUDE.md · 93 lines

How it starts

The opening of the file, as written. The whole thing — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

Contextception is a code context intelligence engine written in Go. It answers: "What code must be understood before making a safe change?" It is not a code generator, AI assistant, or IDE — it determines what matters, not what to do.

Supports 6 languages: Python, TypeScript/JavaScript, Go, Java, Rust, and C#. Available as a CLI (16 commands) and MCP server (9 tools).

Tech Stack

Language: Go (single binary, concurrency for indexing)
Storage: SQLite via modernc.org/sqlite (pure-Go, embedded)
CLI: spf13/cobra
TS/JS Extraction: smacker/go-tree-sitter (CGO) with regex fallback
MCP Server: modelcontextprotocol/go-sdk (stdio transport)
Config: gopkg.in/yaml.v3
Semver: golang.org/x/mod/semver
Release Signing: jedisct1/go-minisign (signature verification for self-update)

Architecture

See docs/ARCHITECTURE.md for the full architecture guide with diagrams.

Repository → Language Extractors → SQLite Index → Analysis Engine → Context Bundle (JSON)

Key components: Indexer (internal/indexer/), Language Extractors (internal/extractor/), Resolvers (internal/resolver/), Analysis Engine (internal/analyzer/), Change Analysis (internal/change/), MCP Server (internal/mcpserver/), Update (internal/update/).

Key Design Principles

Deterministic first — outputs are explainable and reproducible; no model-dependent core logic
Static truth before AI — signals from dependency graphs, repo structure, change patterns
Read-only by design — never modifies source, never executes arbitrary commands
Incremental — only changed files reprocessed; schema migrations are versioned
Pluggable extractors — language-specific extractors emit facts; core is language-agnostic

Development

make build      # Build binary to ./bin/contextception
make test       # Run all tests
make lint       # Run golangci-lint
make check      # Run vet + lint + test
make coverage   # Generate HTML coverage report
make install    # go install to $GOPATH/bin
make generate   # Regenerate protocol JSON schemas
make release    # Show release info (latest tag, next version, pending commits)
make help       # List all targets
/release        # Full release: generate changelog, commit, tag, push (Claude Code)

Read the full file on GitHub · 93 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.

2mo ago First seen · 93 lines · 1,007 tokens per session scan A f86606fa2271

Subscribe to this mod's changes

contextception CLAUDE.md is an instructions file published in the GitHub repository kehoej/contextception (6 stars, last pushed 3mo ago), licensed MIT. It adds 1,007 tokens to every session, about $0.0040 per session on Opus 5.5. 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.

Building agents Memory and context code-context dependency-graph developer-tools go mcp static-analysis

contextception CLAUDE.md next to 6 instructions from other repositories
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contextception CLAUDE.mdkehoej/contextception	Instructions file	6	3mo ago	MIT	A	1,007	Claude Code
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contextception: Instructions file for Claude Code