Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/lesleslie/css-mcp/agents-mdgit clone --depth 1 https://github.com/lesleslie/css-mcpWhat 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 | $0.00378 | $0.00378 |
| Opus 5 | $0.00189 | $0.00189 |
| Sonnet 5 | $0.00076 | $0.00076 |
| Haiku 4.5 | $0.00038 | $0.00038 |
Grade A, and why
css-mcp 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 yesterday.
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
Repository Guidelines
Project Structure & Module Organization
css_mcp/contains the MCP server package, including tool implementations, parsing or analysis helpers, and server entrypoints.- Tests should live under
tests/, mirroring package structure when practical. - Root files such as
pyproject.toml,uv.lock, andREADME.mddefine packaging, dependency, and operator guidance; keep behavioral documentation there rather than scattering it across scripts. - Generated output in
dist/or coverage artifacts should not be edited manually.
Build, Test, and Development Commands
uv sync --group devinstalls development dependencies.uv run pytestruns the full test suite.uv run mypy css_mcpvalidates typing.uv run ruff check css_mcp testsanduv run ruff format css_mcp testscover linting and formatting.- Run the MCP server with the repo's documented local command before validating tool behavior.
Coding Style & Naming Conventions
- Use explicit type hints, small focused modules, and structured tool inputs and outputs.
- Keep module names snake_case and classes PascalCase.
- Prefer extending existing CSS analysis or documentation helpers rather than adding parallel tool paths.
Testing Guidelines
- Add tests with each tool or parser change, especially around CSS analysis edge cases and response formatting.
- Prefer deterministic fixture inputs over live or generated CSS blobs unless the case requires end-to-end validation.
- Review coverage locally after larger changes.
Commit & Pull Request Guidelines
- Use focused commits such as
fix(parser): handle nested rule output. - PRs should describe changed tools, commands run for validation, and any user-facing output differences.
Security & Configuration Tips
- Validate file paths and CSS inputs rigorously.
- Keep secrets and machine-specific paths out of version control.
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.
- yesterday First seen · 39 lines · 378 tokens per session scan A 3ee47899eaff
css-mcp AGENTS.md is an instructions file published in the GitHub repository lesleslie/css-mcp (1 stars, last pushed 3d ago), licensed BSD-3-Clause. It adds 378 tokens to every session, about $0.0019 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.
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