Borrowing it
Nothing to install: this file belongs to major/pcp-mcp. 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/major/pcp-mcp/main/.github/copilot-instructions.mdgit clone --depth 1 https://github.com/major/pcp-mcpWrote 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/major/pcp-mcp/copilot-instructions)<a href="https://agentmods.dev/instructions/major/pcp-mcp/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/major/pcp-mcp/copilot-instructions/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/major/pcp-mcp/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/major/pcp-mcp/copilot-instructions.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 | $0.00931 | $0.00931 |
| Opus 5.5 | $0.00372 | $0.00372 |
| Sonnet 5.5 | $0.00186 | $0.00186 |
| Haiku 4.5 | $0.00093 | $0.00093 |
Grade A, and why
pcp-mcp 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 1mo 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 — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GitHub Copilot Code Review Instructions
Review Philosophy: Invert, Always Invert
Apply Charlie Munger's inversion principle: Instead of asking "Is this code good?", ask "What would make this code fail?"
Focus on preventing failure rather than achieving brilliance:
- What edge cases would break this?
- What would cause this to fail in production?
- What would make this unmaintainable in 6 months?
- What security holes does this open?
When something could fail, explain HOW it would fail and suggest the prevention.
Project Context: pcp-mcp
MCP (Model Context Protocol) server for Performance Co-Pilot (PCP). Python 3.10+, FastMCP 3.1+.
Tech Stack
- MCP Framework: FastMCP 3.1+
- HTTP Client: httpx (async)
- Backend: pmproxy REST API
- Type checking: ty
- Linting/Formatting: ruff
- Testing: pytest + pytest-asyncio + respx
- Package manager: uv
Key Design Decisions
- Clumped tools (get_system_snapshot) instead of per-metric tools
- Client-side rate calculation for counter metrics
- Configurable target_host for remote monitoring
- Pydantic response models with assessment fields
Inversion Checklists by File Type
Source Code (src/pcp_mcp/**/*.py)
MCP server failures to prevent:
- Tools not returning proper Pydantic response models
- Not handling httpx exceptions (must convert to
ToolError) - Blocking calls in async tool functions
- Missing type hints or docstrings
- Rate calculation errors (counter vs gauge metrics)
FastMCP patterns to enforce:
- Tools use
@mcp.tool()decorator with proper type hints - Resources use
@mcp.resource()decorator - Context accessed via
ctx.request_context.lifespan_context - Errors raised as
ToolErrororResourceError
Client (src/pcp_mcp/client.py)
What would cause the client to fail?
- Not creating pmapi context on
__aenter__ - Not closing httpx client on
__aexit__ - Rate calculation with wrong elapsed time
- Not handling counter wrap-around
- Timeout not respected
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.
- 1mo ago First seen · 121 lines · 931 tokens per session scan A 10efcdaef5e3
pcp-mcp copilot-instructions.md is an instructions file published in the GitHub repository major/pcp-mcp (0 stars, last pushed 2mo ago), licensed MIT. It adds 931 tokens to every session, about $0.0037 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.
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