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centian: Instructions file for Codex

AGENTS.md

centian AGENTS.md is an instructions file for Codex, OpenCode from T4cceptor/centian. It costs 951 tokens per session, scanned A, original, Apache-2.0.

Repository instructions for Centian, a Go command-line application that acts as a proxy between MCP clients and other MCP services. A proxy is an intermediary that forwards and can inspect or change requests and responses.

In plain words
What is it for?
Use them when modifying Centian’s command-line interface, proxy connections, request processing, logging, authentication, server, or command completion features.
Why use it?
They explain the project’s purpose, source layout, and development conventions so changes fit the existing codebase.

Instructions file for CodexOpenCode

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

This is T4cceptor/centian's own configuration. It tells Codex and OpenCode how to work on centian 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 centian configures →

not rated 16repo 4mo ago A scan 951 tokens original Apache-2.0
View source ↗ T4cceptor/centian centian.ai
Reuse

Borrowing it

Nothing to install: this file belongs to T4cceptor/centian. 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/T4cceptor/centian/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/T4cceptor/centian

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 centian AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/t4cceptor/centian/agents-md/github.svg)](https://agentmods.dev/instructions/t4cceptor/centian/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/t4cceptor/centian/agents-md"><img src="https://agentmods.dev/badge/instructions/t4cceptor/centian/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 centian AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/t4cceptor/centian/agents-md"><img src="https://agentmods.dev/badge/instructions/t4cceptor/centian/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 951 This file is loaded in full into every session.
When invoked 951 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 $0.00951 $0.00951
Opus 5.5 $0.00380 $0.00380
Sonnet 5.5 $0.00190 $0.00190
Haiku 4.5 $0.00095 $0.00095

Measured 2mo ago against content hash 1a985b0d2c11, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

centian 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 2mo 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 · 55 lines

How it starts

The opening of the file, as written. The whole thing — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Repository Guidelines (Source of Truth)

This file is authoritative for repo workflows, structure, and expectations. Other agent guidance should link here and avoid duplication.

Repository Identity & Purpose

Centian is the MCP proxy for this repository.

  • Repository owner: T4cceptor
  • Repository name: centian
  • Repository URL: https://github.com/T4cceptor/centian
  • Primary role: proxy MCP communication through a single CLI-managed endpoint
  • Core capabilities:
    • Proxy MCP communication to downstream systems
    • Log and monitor MCP requests and results
    • Process requests and responses to inspect, modify, or block them
    • Aggregate downstream systems behind one endpoint, using tool namespacing to keep them distinguishable

Project Structure & Module Organization

Centian is a Go CLI application. The executable entrypoint lives in cmd/main.go.

Basic repository structure:

  • cmd/: CLI entrypoint and top-level command wiring
  • internal/cli/: command handlers for config, logs, auth, processor, server, and completion flows
  • internal/proxy/: MCP proxy server, downstream connection handling, tool-call context, and request/response processing hooks
  • internal/logging/: log readers and shared logging helpers
  • internal/config/: config models, validation, accessors, and config-oriented CLI operations
  • internal/processor/: processor interfaces, scaffolding, and CLI processor execution support
  • internal/config/: config models, validation, persistence, config CLI operations, and import of existing MCP config files
  • internal/auth/: API key and authentication helpers
  • internal/common/: shared MCP models, auth context, utilities, and internal logging primitives
  • docs/: architecture and setup documentation
  • demo/: demo assets, configs, and supporting scripts
  • scripts/: repository scripts
  • tests/test_configs/: config fixtures and sample MCP client/server configs
  • tests/integrationtests/: end-to-end and processor integration coverage
  • build/: compiled binaries and generated artifacts

Read the full file on GitHub · 55 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. 2mo ago First seen · 55 lines · 951 tokens per session scan A 1a985b0d2c11

Subscribe to this mod's changes

centian AGENTS.md is an instructions file published in the GitHub repository T4cceptor/centian (16 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 951 tokens to every session, about $0.0038 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.

aiai-agentai-agentsai-governancemcpmcp-server
Related

centian AGENTS.md compared with instructions from other repositories

centian AGENTS.md next to 6 instructions from other repositories
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centian AGENTS.mdT4cceptor/centianInstructions file164mo agoApache-2.0A951Codex, OpenCode
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vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode