open-agent-sdk: Instructions file for Codex

AGENTS.md

open-agent-sdk AGENTS.md is an instructions file for Codex, OpenCode from OasAIStudio/open-agent-sdk. It costs 551 tokens per session, scanned A, original, MIT.

Repository instructions for developing Open Agent SDK, a TypeScript toolkit for building AI agents that use tools and different AI providers. They describe the project layout, required software, commands, and testing-first rules.

In plain words
What is it for?
Use them when modifying the SDK, running its Bun build and tests, checking types, or adding agent, tool, provider, or permission features.
Why use it?
They give a coding agent the project’s source of truth and working conventions. This reduces the risk of changing the wrong package or skipping required checks.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions CLAUDE.md; mentions subagents; mentions Claude Code.

This is OasAIStudio/open-agent-sdk's own configuration. It tells Codex and OpenCode how to work on open-agent-sdk 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 open-agent-sdk configures →

Reuse

Borrowing it

Nothing to install: this file belongs to OasAIStudio/open-agent-sdk. 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/OasAIStudio/open-agent-sdk/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/OasAIStudio/open-agent-sdk

Made for: Codex, OpenCode.

Wrote this? Show the measurements

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README.md
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Per session 551 This file is loaded in full into every session.
When invoked 551 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 $0.00551 $0.00551
Opus 5 $0.00275 $0.00275
Sonnet 5 $0.00110 $0.00110
Haiku 4.5 $0.00055 $0.00055

Measured 6d ago against content hash cc635ab546fe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

open-agent-sdk 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 6d 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 · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Open Agent SDK - Codex Agent Guide

This file defines how Codex should work in this repository.

Goal

Build and maintain a TypeScript SDK for AI agents with tool use, ReAct loop, and multi-provider support.

Source Of Truth

  • Product requirements: REQUIREMENTS.md
  • Architecture decisions: docs/adr/
  • Gap analysis: docs/gap-analysis.md
  • Git workflow: docs/workflows/git-workflow.md
  • Testing guide: docs/workflows/testing-guide.md

Repository Layout

  • Root workspace: Bun workspaces monorepo
  • Core package: packages/core/
  • Source code: packages/core/src/
  • Tests: packages/core/tests/ (mirror src/ structure)

Runtime And Language

  • Runtime: Bun >= 1.0.0
  • Language: TypeScript 5.x, strict mode

Commands

  • Install deps: bun install
  • Build: bun run build
  • Test: bun test
  • Coverage: bun test --coverage
  • Type check: bun run typecheck

For integration tests with real LLM APIs:

env $(cat .env | xargs) bun test

Engineering Rules

TDD Policy

Use tests-first for:

  • Core agent logic (ReAct loop, tool execution, subagent spawning)
  • Tool implementations
  • Provider integrations
  • Permission system

Tests-after is acceptable for:

  • Docs changes
  • Config updates
  • Simple utilities
  • Obvious low-risk fixes

Quality Bar

  • Keep public APIs fully typed
  • Preserve backward compatibility unless explicitly requested
  • Add or update tests for behavior changes
  • Keep changes minimal and focused (one logical change per PR)

Git And PR

  • Use Conventional Commits: type(scope): description
  • PR title/description/comments in English
  • Never push new changes to a branch whose PR is already merged
  • If branch is merged, create a new branch from latest main

Codex-Specific Operating Rules

  • Prefer rg for search (rg --files for file listing)
  • Read before edit; avoid broad refactors unless required
  • Do not run destructive git commands unless explicitly requested
  • Do not revert unrelated local changes
  • Validate with targeted tests first, then broader tests if needed
  • Summarize exact files changed and verification commands run

Read the full file on GitHub · 85 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. 6d ago First seen · 85 lines · 551 tokens per session scan A cc635ab546fe

Subscribe to this mod's changes

open-agent-sdk AGENTS.md is an instructions file published in the GitHub repository OasAIStudio/open-agent-sdk (46 stars, last pushed 5mo ago), licensed MIT. It adds 551 tokens to every session, about $0.0028 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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