What is flatmachines AGENTS.md?

A reference guide for FlatAgents and FlatMachines, tools for defining single model calls and multi-step workflows. It also explains model profiles and sign-in connections for Codex and Copilot.

Use it when building or reviewing flatagents, flatmachines, model-profile files, prompts, or related configuration.

It helps developers choose the right structure for a simple task or a workflow with branching, retries, parallel work, or background tasks. It also documents how models are selected.

How memgrafter/flatmachines configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to memgrafter/flatmachines. 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/memgrafter/flatmachines/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/memgrafter/flatmachines

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/memgrafter/flatmachines/agents-md/github.svg)](https://agentmods.dev/instructions/memgrafter/flatmachines/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/memgrafter/flatmachines/agents-md"><img src="https://agentmods.dev/badge/instructions/memgrafter/flatmachines/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/memgrafter/flatmachines/agents-md"><img src="https://agentmods.dev/badge/instructions/memgrafter/flatmachines/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 2,185 This file is loaded in full into every session.

When invoked 2,185 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.

Model	Per session	Once invoked
Fable 5.1	$0.02185	$0.02185
Opus 5.5	$0.00874	$0.00874
Sonnet 5.5	$0.00437	$0.00437
Haiku 4.5	$0.00218	$0.00218

Measured 2mo ago against content hash 1566e79fca1a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

flatmachines 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 · 217 lines

How it starts

The opening of the file, as written. The whole thing — 217 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FlatAgents + FlatMachines Reference

Target: <1000 tokens. LLM-optimized. See flatagent.d.ts, flatmachine.d.ts, profile.d.ts, prompt.d.ts for schemas.

Versioning: All specs and SDKs use lockstep versioning.

Concepts

FlatAgent: Single LLM call. Model + prompts + output schema. No orchestration. FlatMachine: State machine orchestrating agents. States, transitions, conditions, loops, error handling.

Need	Use
Single LLM call	FlatAgent
Multi-step/branching/retry/errors	FlatMachine
Parallel execution	`machine: [a, b, c]`
Dynamic parallelism	`foreach`
Background tasks	`launch`

Model Profiles

# profiles.yml — agents reference by name
spec: flatprofile
spec_version: "4.2.1"
data:
  model_profiles:
    fast: { provider: cerebras, name: zai-glm-4.6, temperature: 0.6 }
    smart: { provider: anthropic, name: claude-3-opus-20240229 }
  default: fast        # Fallback
  # override: smart    # Force all

Agent model field: "fast" | { profile: "fast", temperature: 0.9 } | { provider: x, name: y } Resolution: default → profile → overrides → override

OAuth Backends (Codex / Copilot)

backend: codex and backend: copilot are explicit-only (never auto-detected).
Backend selection precedence remains: constructor backend → resolved model.backend → auto-detect (litellm/aisuite only).
oauth settings are read from resolved model config; works identically whether model came from inline agent config or profile.
Auth file precedence:
- Codex: oauth.auth_file → legacy codex_auth_file → legacy auth.auth_file → FLATAGENTS_CODEX_AUTH_FILE → ~/.pi/agent/auth.json
- Copilot: oauth.auth_file → copilot_auth_file → legacy auth.auth_file → FLATAGENTS_COPILOT_AUTH_FILE → ~/.agents/flatmachines/auth.json
Token handling: pre-request refresh on expiry; if refresh fails, re-read auth store once for cross-process refresh; fallback refresh+retry on 401/403.
Retries on 429/500/502/503/504 with exponential backoff (no jitter).

Read the full file on GitHub · 217 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.

2mo ago First seen · 217 lines · 2,185 tokens per session scan A 1566e79fca1a

Subscribe to this mod's changes

flatmachines AGENTS.md is an instructions file published in the GitHub repository memgrafter/flatmachines (37 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 2,185 tokens to every session, about $0.0087 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.

Building agents Orchestration agents ai ai-agents llms specification

flatmachines AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
flatmachines AGENTS.mdmemgrafter/flatmachines	Instructions file	37	5mo ago	Apache-2.0	A	2,185	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

flatmachines: Instructions file for Codex