Borrowing it
Nothing to install: this file belongs to plumpslabs/matcha. 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/plumpslabs/matcha/main/.github/copilot-instructions.mdgit clone --depth 1 https://github.com/plumpslabs/matchaWrote 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/plumpslabs/matcha/copilot-instructions)<a href="https://agentmods.dev/instructions/plumpslabs/matcha/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/plumpslabs/matcha/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/plumpslabs/matcha/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/plumpslabs/matcha/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 | $0.00468 | $0.00468 |
| Opus 5.5 | $0.00187 | $0.00187 |
| Sonnet 5.5 | $0.00094 | $0.00094 |
| Haiku 4.5 | $0.00047 | $0.00047 |
Grade A, and why
matcha 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.
What it actually says
🍵 matcha — Engineering Convention
This project uses the matcha engineering convention. Read the AGENTS.md file at the project root and follow its philosophy:
Simple. Efficient. Deliberate. Never twice.
Key principles (see AGENTS.md for the full ruleset):
-
⚖️ Proportionality (effort ↔ risk) — match ceremony to task size. Trivial (≤5 LOC, 1 file, no logic): minimal plan, fast pass. Small (1-3 files): short plan + light review. Large (cross-cutting/prod risk): full gate. Planning > implementation = over-planning. Exit conditions beat STOP — proceed on a recorded assumption rather than blocking on trivia.
-
Purpose (Intent Discovery) — know why before how. Can't explain why/how? Stop and rethink — unless the task is trivial, then proceed on a recorded assumption.
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Reuse — search the codebase before writing new code. Never write what exists.
-
Implementation — scalable and modular, never golfed. Do not sacrifice types, error handling, or modularity for brevity. One function, one job. Explicit errors. No hardcoded values. Validate inputs at boundaries. Never log secrets/PII.
-
Cleanup — done means working and clean. No debug leftovers, no dead code.
-
Verify — run tests, typecheck, and lint before declaring done.
-
⚡ Parallel Discovery — run Intent Discovery & Symbol search concurrently before code generation.
-
🔎 Symbol-First Reuse — prioritize AST/LSP symbol graphs across all programming languages.
-
🧪 Smart Test Scoping — run affected unit tests during fast iterations; full suites in CI.
-
🚦 Adaptive Intensity — observe (docs/styling) → enforce (standard logic) → audit (security/auth/DB/billing).
-
🐻 Kuma Companion — If Kuma MCP is available, use
kuma_contextfor blast radius/impact,kuma_memoryfor gotchas, andkuma_safetyfor verification.
Respect the // matcha: decision markers when you find them in code — they are intentional, logged shortcuts.
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 Changed · +1 lines · +68 tokens per session 085625a0e5a9
- 1mo ago Changed · +6 lines · +97 tokens per session 2aef94cb170c
- 1mo ago First seen · 16 lines · 303 tokens per session scan A fbf62797f33f
matcha copilot-instructions.md is an instructions file published in the GitHub repository plumpslabs/matcha (2 stars, last pushed 5d ago), licensed MIT. It adds 468 tokens to every session, about $0.0019 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
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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.
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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.
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).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.