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mcp-server-check: Instructions file for Codex

AGENTS.md

mcp-server-check AGENTS.md is an instructions file for Codex, OpenCode from check-technologies/mcp-server-check. It costs 780 tokens per session, scanned A, original, MIT.

Repository instructions for a Python package and command-line tool that connect to Check Payroll API, a remote service for payroll data, through an MCP server. MCP lets AI tools call external services.

In plain words
What is it for?
Use them when changing the Check API client, MCP tools, command-line commands or tests, and when running the local server.
Why use it?
They document the required Python environment, service settings and checks, including tests that use mocked network calls instead of contacting the real API.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions AGENTS.md.

This is check-technologies/mcp-server-check's own configuration. It tells Codex and OpenCode how to work on mcp-server-check 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-server-check configures →

not rated 18repo changed 2d ago A scan 780 tokens original MIT
View source ↗ check-technologies/mcp-server-check
Reuse

Borrowing it

Nothing to install: this file belongs to check-technologies/mcp-server-check. 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/check-technologies/mcp-server-check/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/check-technologies/mcp-server-check

Made for: Codex, OpenCode.

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Per session 780 This file is loaded in full into every session.
When invoked 780 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 $0.00780 $0.00780
Opus 5.5 $0.00312 $0.00312
Sonnet 5.5 $0.00156 $0.00156
Haiku 4.5 $0.00078 $0.00078

Measured 2d ago against content hash a389e75a580b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-server-check 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 2d 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.

AGENTS.md · 46 lines

How it starts

The opening of the file, as written. The whole thing — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Cursor Cloud specific instructions

This repo is mcp-server-check: a Python (>=3.10) package providing both an MCP server (mcp-server-check) and a CLI (check) for the Check Payroll API. It is managed with uv; dependencies are locked in uv.lock. There is no database, frontend, or other service — the only "backend" it talks to is the remote Check API (https://sandbox.checkhq.com by default).

The update script runs uv sync --frozen, so dependencies and the .venv are already in place when a session starts. Run all commands through uv run (they execute inside .venv).

Lint / test / build (see .github/workflows/ci.yml)

  • Lint: uv run ruff check src/ tests/ and uv run ruff format --check src/ tests/
  • Tests: uv run pytest tests/ — 465 tests. Tests need no API key or network; HTTP is mocked with respx.
  • Optional git hooks mirroring CI lint: uv run pre-commit install (config in .pre-commit-config.yaml).

Running the services

  • MCP server: uv run mcp-server-check. Requires CHECK_API_KEY (exits with an error otherwise). Defaults to stdio transport and "dynamic" tool mode (exposes 3 meta-tools: search_tools, list_toolsets, run_tool). Env knobs: CHECK_TOOL_MODE=all (legacy all-tools), CHECK_TRANSPORT, CHECK_ENV / CHECK_API_BASE_URL, CHECK_READ_ONLY, CHECK_TOOLSETS, CHECK_TOOLS, CHECK_EXCLUDE_TOOLS, CHECK_EXCLUDE_MONEY_MOVEMENT, CHECK_EXCLUDE_DESTRUCTIVE, CHECK_PREVIEW_TOOLSETS.
  • Preview toolsets are hidden unless opted into via CHECK_PREVIEW_TOOLSETS, the x-mcp-preview-toolsets header, the preview_toolsets query parameter, or the CLI's --preview-toolsets.
  • CLI: uv run check ... (see CLI.md). check --help, check --version, and check init <target> work without a key; any command that hits the API needs CHECK_API_KEY (passed via --api-key or env). Defaults to the sandbox environment.

Non-obvious notes

  • Tests and --help/init work offline; live API calls (and starting the MCP server) require a valid CHECK_API_KEY secret.
  • Prefer a sandbox key for testing. Sandbox (https://sandbox.checkhq.com) is the default environment for both the CLI and MCP server, supports the simulate-* endpoints, and write operations there move no real money. A production key (--env production / https://api.checkhq.com) touches real payroll data — only use it for read-only checks.
  • To exercise tool round-trips without any key, mock the HTTP layer with respx (as the tests do) and drive the in-memory server via fastmcp's Client(mcp).
  • pyproject.toml requires fastmcp>=3.4.4 (tool errors rely on its per-error log_level), and uv.lock pins the version the hosted connector runs; use uv sync --frozen to stay consistent with CI.

Read the full file on GitHub · 46 lines

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. 2d ago Changed · +1 lines · +18 tokens per session a389e75a580b
  2. 23d ago Changed · +4 lines · +69 tokens per session 50b948faf550
  3. 1mo ago First seen · 41 lines · 693 tokens per session scan A f7714254eb04

Subscribe to this mod's changes

mcp-server-check AGENTS.md is an instructions file published in the GitHub repository check-technologies/mcp-server-check (18 stars, last pushed today), licensed MIT. It adds 780 tokens to every session, about $0.0031 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 2026-08-30.

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