x-signal: Instructions file for Codex

AGENTS.md

x-signal AGENTS.md is an instructions file for Codex, OpenCode from anotb/x-signal. It costs 491 tokens per session, scanned A, original, MIT.

A set of project instructions for installing and maintaining X Signal, a local service that connects coding agents to X. It covers setup, health checks, browser sign-in, security, and credential handling.

In plain words
What is it for?
Use it when installing X Signal, connecting a Codex client to its local MCP endpoint, checking service readiness, recovering browser sign-in issues, or changing the project.
Why use it?
It gives an agent clear rules for operating the service safely, including keeping services local and avoiding requests for sensitive session information in chat.

Instructions file for CodexOpenCode

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

This is anotb/x-signal's own configuration. It tells Codex and OpenCode how to work on x-signal 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 x-signal configures →

Reuse

Borrowing it

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

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 x-signal AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/anotb/x-signal/agents-md.svg)](https://agentmods.dev/instructions/anotb/x-signal/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/anotb/x-signal/agents-md"><img src="https://agentmods.dev/badge/instructions/anotb/x-signal/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 491 This file is loaded in full into every session.
When invoked 491 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00491 $0.00491
Opus 5 $0.00246 $0.00246
Sonnet 5 $0.00098 $0.00098
Haiku 4.5 $0.00049 $0.00049

Measured 5d ago against content hash 377d0bc48786, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

x-signal 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 5d 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 · 23 lines

How it starts

The opening of the file, as written. The whole thing — 23 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Working with X Signal

Installing for a user

  • Detect the operating system and confirm Docker Compose is available before changing anything.
  • Keep the default services and ports bound to loopback.
  • Start with docker compose up -d --build --wait, then check /healthz, /readyz, and docker compose ps.
  • Connect local Codex clients to http://127.0.0.1:7345/mcp.
  • Never ask a user to paste cookies, session tokens, VNC passwords, tunnel URLs, or other credentials into chat.
  • Prefer a dedicated Chrome profile with the session companion. A profile selected during active research is queued and should complete through automatic sync; do not ask for a second activation click. Use noVNC for visible sign-in or challenge recovery.
  • Do not bypass X authentication, challenges, access controls, or rate limits.
  • For ChatGPT web, use the opt-in chatgpt Secure MCP Tunnel profile. Help the user create a workspace-associated tunnel and a runtime key restricted to Tunnels Read + Use, then ask them to enter both directly into npm run tunnel:secure:configure; its key prompt is hidden. Never capture, print, repeat, or commit either value. Use npm run tunnel:chatgpt only as an explicitly short-lived fallback, and never expose port 7345 directly.
  • Explain every visible step the user must perform and verify the final X identity without repeating its handle in public logs.

Changing the project

  • Keep the architecture tool-only unless a real user workflow requires UI.
  • Preserve one persistent browser, concurrency two, request spacing, durable jobs, account-bound provenance, and adaptive backoff.
  • Do not add posting, generic browser automation, CAPTCHA handling, proxy rotation, or enforcement-evasion features.
  • Use synthetic parser fixtures. Never commit captured posts, account handles, browser data, exports, registrations, tunnel identifiers, credentials, temporary URLs, or local paths. The only image exception is an explicitly allowlisted public showcase capture under docs/assets that has been manually checked against SECURITY.md.
  • Run npm run validate, npm audit --audit-level=moderate, docker compose config --quiet, and the plugin/skill validators before release.
  • Treat live tests as real account traffic. Use the smallest canary that proves the change and do not leave test monitors running.

Read the full file on GitHub · 23 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. 5d ago First seen · 23 lines · 491 tokens per session scan A 377d0bc48786

Subscribe to this mod's changes

x-signal AGENTS.md is an instructions file published in the GitHub repository anotb/x-signal (1 stars, last pushed 22d ago), licensed MIT. It adds 491 tokens to every session, about $0.0025 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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