mcp-one: Instructions file for Codex

AGENTS.md

mcp-one AGENTS.md is an instructions file for Codex, OpenCode from Miguell-J/mcp-one. It costs 193 tokens per session, scanned A, original, MIT.

Repository instructions for MCP One, an infrastructure server that connects multiple MCP servers and presents them through one interface to AI models or applications. They set rules for protocol compatibility, routing, testing, logging, configuration, and resource cleanup.

In plain words
What is it for?
Use them when modifying MCP routing, protocol handling, configuration, registry refreshes, client lifecycles, logging, or automated checks in the MCP One project.
Why use it?
They help maintain a central integration layer without adding application-specific logic or accidentally changing the data and error information passed through it. They also require stronger tests for routing and protocol changes.

Instructions file for CodexOpenCode

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

This is Miguell-J/mcp-one's own configuration. It tells Codex and OpenCode how to work on mcp-one 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-one configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Miguell-J/mcp-one. 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/Miguell-J/mcp-one/master/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/Miguell-J/mcp-one

Made for: Codex, OpenCode.

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-one AGENTS.md

README.md
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Your own site
<a href="https://agentmods.dev/instructions/miguell-j/mcp-one/agents-md"><img src="https://agentmods.dev/badge/instructions/miguell-j/mcp-one/agents-md/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.

agentmods 80×15 button for mcp-one AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/miguell-j/mcp-one/agents-md"><img src="https://agentmods.dev/badge/instructions/miguell-j/mcp-one/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 193 This file is loaded in full into every session.
When invoked 193 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 $0.00193 $0.00193
Opus 5 $0.00097 $0.00097
Sonnet 5 $0.00039 $0.00039
Haiku 4.5 $0.00019 $0.00019

Measured today against content hash 52ee5a166407, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-13, from the pricing page.

Security

Grade A, and why

mcp-one 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 today.

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 · 15 lines

What it actually says

Working on MCP One

  • MCP One is infrastructure only. Never put domain logic here.
  • Native MCP is the primary protocol, using public official SDK interfaces.
  • Never degrade downstream schemas, content, structuredContent, isError or _meta.
  • Never retry mutating tools blindly. Annotations alone do not authorize retries.
  • Never open infrastructure circuits on domain errors or caller validation errors.
  • Never log secrets, headers or payload bodies by default.
  • All routing changes require tests; protocol changes require real SDK contract/E2E tests.
  • Architecture changes require an ADR and updated operational documentation.
  • Use uv and the committed lock, Ruff and strict mypy. Python 3.12–3.14.
  • Keep registry snapshots consistent during refresh. Close clients and cancel background work.
  • Configuration is trusted operator input. Do not add remote configuration mutation.
  • Run make check and real HTTP tests before committing. Report unexecuted checks honestly.
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. today First seen · 15 lines · 193 tokens per session scan A 52ee5a166407

Subscribe to this mod's changes

mcp-one AGENTS.md is an instructions file published in the GitHub repository Miguell-J/mcp-one (5 stars, last pushed today), licensed MIT. It adds 193 tokens to every session, about $0.0010 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 2026-09-13.

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