alethfeld: Instructions file for Codex

AGENTS.md

alethfeld AGENTS.md is an instructions file for Codex, OpenCode from tobiasosborne/alethfeld. It costs 444 tokens per session, scanned A, original, MIT.

Agent instructions for a Lean project, where Lean is a programming language and proof system used to verify mathematical statements. They describe the project’s issue tracker, build checks, proof-workflow documents, and session-closing process.

In plain words
What is it for?
Use them when starting or finishing work in the project. They cover finding and updating issues, reviewing Lean library documentation, running the build, recording follow-up work, and syncing completed changes.
Why use it?
They provide the required order for finding work, checking for regressions, updating issues, and finishing a contribution. This helps keep code changes and proof work recorded and synchronized.

Instructions file for CodexOpenCode

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

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

Reuse

Borrowing it

Nothing to install: this file belongs to tobiasosborne/alethfeld. 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/tobiasosborne/alethfeld/legacy/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/tobiasosborne/alethfeld

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 alethfeld AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/tobiasosborne/alethfeld/agents-md.svg)](https://agentmods.dev/instructions/tobiasosborne/alethfeld/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/tobiasosborne/alethfeld/agents-md"><img src="https://agentmods.dev/badge/instructions/tobiasosborne/alethfeld/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 444 This file is loaded in full into every session.
When invoked 444 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 $0.00444 $0.00444
Opus 5 $0.00222 $0.00222
Sonnet 5 $0.00089 $0.00089
Haiku 4.5 $0.00044 $0.00044

Measured 8d ago against content hash b5750e2f1c89, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

alethfeld 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 8d 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 · 47 lines

What it actually says

Agent Instructions

This project uses bd (beads) for issue tracking. Run bd onboard to get started.

Quick Reference

bd ready              # Find available work
bd show <id>          # View issue details
bd update <id> --status in_progress  # Claim work
bd close <id>         # Complete work
bd sync               # Sync with git

Starting a New Work Session

Before beginning work:

  1. Check bd ready for available work
  2. Review lean/API.md for existing Lean library documentation
  3. Run lake build to verify no regressions
  4. See orchestrator-prompt-v5.1-claude.md for the stable proof orchestration protocol, or orchestrator-prompt-v5_2-claude.md for the experimental v5.2 with explicit state machine

Landing the Plane (Session Completion)

When ending a work session, you MUST complete ALL steps below. Work is NOT complete until git push succeeds.

MANDATORY WORKFLOW:

  1. File issues for remaining work - Create issues for anything that needs follow-up
  2. Run quality gates (if code changed) - Tests, linters, builds
  3. Update issue status - Close finished work, update in-progress items
  4. PUSH TO REMOTE - This is MANDATORY:
    git pull --rebase
    bd sync
    git push
    git status  # MUST show "up to date with origin"
    
  5. Clean up - Clear stashes, prune remote branches
  6. Verify - All changes committed AND pushed
  7. Hand off - Provide context for next session

CRITICAL RULES:

  • Work is NOT complete until git push succeeds
  • NEVER stop before pushing - that leaves work stranded locally
  • NEVER say "ready to push when you are" - YOU must push
  • If push fails, resolve and retry until it succeeds
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. 8d ago First seen · 47 lines · 444 tokens per session scan A b5750e2f1c89

Subscribe to this mod's changes

alethfeld AGENTS.md is an instructions file published in the GitHub repository tobiasosborne/alethfeld (144 stars, last pushed 3mo ago), licensed MIT. It adds 444 tokens to every session, about $0.0022 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 2026-08-30.

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