mcp-slim-guard: Instructions file for GitHub Copilot

.github/copilot-instructions.md

mcp-slim-guard copilot-instructions.md is an instructions file for GitHub Copilot from lennney/mcp-slim-guard. It costs 171 tokens per session, scanned A, original, MIT.

A short set of Copilot review instructions for mcp-slim-guard, with AGENTS.md as the main source of project rules.

In plain words
What is it for?
Use it when reviewing changes to tool execution, result recovery, authorization boundaries, tests, logs, private evaluation material, or release actions.
Why use it?
It highlights security, correctness, testing, boundary, logging, and benchmark-claim issues that reviewers should catch.

Instructions file for GitHub Copilot

Written for GitHub Copilot: a Copilot instructions file. Also seen: mentions AGENTS.md.

This is lennney/mcp-slim-guard's own configuration. It tells GitHub Copilot how to work on mcp-slim-guard itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mcp-slim-guard configures →

Reuse

Borrowing it

Nothing to install: this file belongs to lennney/mcp-slim-guard. 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/lennney/mcp-slim-guard/main/.github/copilot-instructions.md
Clone the repo
git clone --depth 1 https://github.com/lennney/mcp-slim-guard

Made for: GitHub Copilot.

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 mcp-slim-guard copilot-instructions.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/lennney/mcp-slim-guard/copilot-instructions.svg)](https://agentmods.dev/instructions/lennney/mcp-slim-guard/copilot-instructions)
Your own site
<a href="https://agentmods.dev/instructions/lennney/mcp-slim-guard/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/lennney/mcp-slim-guard/copilot-instructions.svg" alt="Measured on agentmods" height="20"></a>
Per session 171 This file is loaded in full into every session.
When invoked 171 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00171 $0.00171
Opus 5 $0.00086 $0.00086
Sonnet 5 $0.00034 $0.00034
Haiku 4.5 $0.00017 $0.00017

Measured 8d ago against content hash 63e4a7895901, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

mcp-slim-guard copilot-instructions.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 8d 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.

.github/copilot-instructions.md · 17 lines

What it actually says

Slim Guard Copilot review rules

AGENTS.md is the source of truth for repository and agent guidance. This file is a short review-focused distillation for Copilot surfaces that do not load the full hierarchy. Update AGENTS.md first when a rule changes.

  • Reject changes that expose unauthorized Tools or allow a business Tool to reach the upstream server more than once.
  • Reject changes that make read_result execute an upstream business Tool or lose exact result recovery.
  • Require deterministic focused tests for behavior changes and the smallest complete verification matrix from AGENTS.md.
  • Treat any, unchecked boundary casts, sensitive logs, private paths, and unsupported benchmark claims as review findings.
  • Keep public runtime code, private evaluation material, and release actions in their separate boundaries.
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. 8d ago First seen · 17 lines · 171 tokens per session scan A 63e4a7895901

Subscribe to this mod's changes

mcp-slim-guard copilot-instructions.md is an instructions file published in the GitHub repository lennney/mcp-slim-guard (192 stars, last pushed 24d ago), licensed MIT. It adds 171 tokens to every session, about $0.0009 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.

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