Getting it into your agent
There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.
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.
[](https://agentmods.dev/instructions/bobmatnyc/mcp-browser/claude-md)<a href="https://agentmods.dev/instructions/bobmatnyc/mcp-browser/claude-md"><img src="https://agentmods.dev/badge/instructions/bobmatnyc/mcp-browser/claude-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.06134 | $0.06134 |
| Opus 5 | $0.03067 | $0.03067 |
| Sonnet 5 | $0.01227 | $0.01227 |
| Haiku 4.5 | $0.00613 | $0.00613 |
Grade A, and why
mcp-browser 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 866 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md - AI Agent Instructions for mcp-browser
Project: MCP Browser - Browser console log capture and control via MCP
Location: /Users/masa/Projects/mcp-browser
Language: Python 3.10+
Architecture: Service-Oriented Architecture (SOA) + Chrome Extension + MCP Server
Last Updated: 2025-12-15
🎯 Priority Index
🔴 CRITICAL Instructions
🟡 IMPORTANT Instructions
🟢 STANDARD Instructions
⚪ OPTIONAL Instructions
🔴 CRITICAL: Architecture Constraints
Service-Oriented Architecture (SOA)
NEVER violate these architectural boundaries:
# ✅ CORRECT: Services communicate through dependency injection
class BrowserService:
def __init__(self, storage_service=None):
self.storage_service = storage_service # Injected dependency
# ❌ WRONG: Direct service instantiation breaks DI
class BrowserService:
def __init__(self):
self.storage_service = StorageService() # Don't do this!
Service Layer Rules:
- All service methods MUST be async - No blocking operations
- 500-line service limit - Enforces single responsibility principle
- Constructor injection only - Dependencies resolved at creation time
- No circular dependencies - Container enforces dependency graph
- Interface segregation - Services expose minimal public APIs
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.
- 5d ago First seen · 866 lines · 6,134 tokens per session scan A 58b0509b7f2d
mcp-browser CLAUDE.md is an instructions file published in the GitHub repository bobmatnyc/mcp-browser (2 stars, last pushed 8mo ago), licensed MIT. It adds 6,134 tokens to every session, about $0.0307 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.
Other instructions, from other repositories
Browser4 CLAUDE.md
Claude Code instructions for platonai/Browser4, covering browser4 — project context for claude, architecture, key dispatch chain (cli → browser), batch commands and e2e test structure.
cc-websearch CLAUDE.md
Claude Code instructions for Djarvur/cc-websearch, covering project, constraints, technology stack, what not to add and conventions.
fix-quera AGENTS.md
Instructions for AlirezaKeshavarz83/fix-quera, covering agent guidance, project shape, visual style, quera page data findings and compatibility findings.
sniff AGENTS.md
AGENTS.md instructions for Aboudjem/sniff, covering agents.md: sniff, what this repo is, how an agent should use sniff, handling the playwright setup gate and finding output schema.
fast-browser CLAUDE.md
Claude Code instructions for m4ttstack/fast-browser, covering fast browser plugin, where a change belongs, fork branch: use fast-browser-runtime, releasing a new runtime and re-pinning this repo: use the script.
sendblue-browser-use AGENTS.md
Instructions for sendblue-api/sendblue-browser-use, covering agents.md — sendblue-browser-use, what this repo is, setup, common commands and health (no auth).