Borrowing it
Nothing to install: this file belongs to cyanheads/attack-surface-mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/cyanheads/attack-surface-mcp-server/main/AGENTS.mdgit clone --depth 1 https://github.com/cyanheads/attack-surface-mcp-serverWrote 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/cyanheads/attack-surface-mcp-server/agents-md)<a href="https://agentmods.dev/instructions/cyanheads/attack-surface-mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/cyanheads/attack-surface-mcp-server/agents-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.
<a href="https://agentmods.dev/instructions/cyanheads/attack-surface-mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/cyanheads/attack-surface-mcp-server/agents-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.08338 | $0.08338 |
| Opus 5.5 | $0.03335 | $0.03335 |
| Sonnet 5.5 | $0.01668 | $0.01668 |
| Haiku 4.5 | $0.00834 | $0.00834 |
Grade A, and why
attack-surface-mcp-server AGENTS.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 7d 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.
This is a copy
78% identical to obsidian-mcp-server AGENTS.md — 398 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 447 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Developer Protocol
Server: attack-surface-mcp-server
Version: 0.4.0
Framework: @cyanheads/mcp-ts-core ^0.13.15
Engines: Bun ≥1.4.0, Node ≥24.0.0
MCP SDK: @modelcontextprotocol/server ^2.3.1
Zod: ^4.6.7
Read the framework docs first:
node_modules/@cyanheads/mcp-ts-core/CLAUDE.mdcontains the full API reference — builders, Context, error codes, exports, patterns. This file covers server-specific conventions only.
Authorized-use posture
This is a defensive external-attack-surface-mapping (EASM) server. It is passive and non-intrusive by mandate: it reads public records (Certificate Transparency, DNS, RDAP/WHOIS) and each target's own published surface (one TLS handshake, one HTTP GET per host). It does not port-scan, exploit, brute-force, fuzz, or probe for vulnerabilities — that capability is excluded from the surface by design, never gated behind a flag. Output is descriptive (what exists, what the posture is), never an exploitation plan.
- Keep the framing in the surface. The server
instructions, theattacksurface_map_domaindescription, andattacksurface_recon_guidanceall state the target must be owned or authorized for assessment. Preserve that when editing any of them. Don't add active/intrusive capability or amode: activetoggle — excluding it structurally is the safety property. - The SSRF guard is the security spine. Every outbound connection to a user-supplied target (DNS, TLS, HTTP) must pass
assertSafeDomain/assertSafeUrl/assertSafeResolverIp(src/utils/ssrf-guard.ts) before connecting. It rejects private, loopback, link-local, cloud-metadata, and reserved ranges. Never route a new outbound path around it. - No fabricated signal. Report detections with their triggering evidence; report absent CT/DNS/RDAP fields as unknown. No invented confidence composites.
- Registration authority and literal evidence. CIDRs require one decimal prefix in the family range; zone identifiers are rejected. RDAP IP paths preserve literal delimiters. WHOIS parses only recognizable authoritative referral responses, with typed
no_matchfor explicit negatives andsource_unavailablefor unavailable/unsupported responses. Normalize allocation ranges to exact CIDRs while retaining invalid text inrawWhois. Registration/HTTP/TLS/DNS/Shodan formatters render upstream values throughliteralText; raw WHOIS uses a complete collision-safe fenced block.
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.
- 7d ago Changed · +4 lines · +122 tokens per session 48a234a66bb3
- 10d ago Changed · +1 lines · +145 tokens per session 754f310db767
- 24d ago Changed · -1 lines · +126 tokens per session 0b19da3f5661
- 1mo ago Changed · +29 lines · +1,305 tokens per session c750d6574578
- 1mo ago First seen · 414 lines · 6,640 tokens per session scan A 632ca3826e97
attack-surface-mcp-server AGENTS.md is an instructions file published in the GitHub repository cyanheads/attack-surface-mcp-server (1 stars, last pushed 6d ago), licensed Apache-2.0. It adds 8,338 tokens to every session, about $0.0334 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 78% identical to obsidian-mcp-server AGENTS.md, differing in 398 lines, and is treated as a copy.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).