haystack: Instructions file for Codex

AGENTS.md

haystack AGENTS.md is an instructions file for Codex, OpenCode from deepset-ai/haystack. It costs 1,897 tokens per session, scanned A, original, Apache-2.0.

A set of instructions for AI agents working in the deepset-ai/haystack repository. It explains the Hatch-based development environment, testing commands, type checking, and dependency practices.

In plain words
What is it for?
Setting up and using Haystack's development environment, running unit or integration tests, checking types, and installing temporary experiment dependencies.
Why use it?
It gives agents the repository's required way to run code and tests, helping avoid unsupported commands or incorrectly configured environments.

Instructions file for CodexOpenCode

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

This is deepset-ai/haystack's own configuration. It tells Codex and OpenCode how to work on haystack 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 haystack configures →

About the project

deepset-ai/haystack is an open-source Python framework for assembling AI applications from modular pipelines that handle tasks such as retrieving information, routing requests, managing memory, and generating responses. It is for developers building retrieval-augmented generation, semantic search, question-answering, multimodal, and agent systems. The catalogue instructions relate to working with this framework.

deepset-ai/haystack · 26,872 stars · on GitHub · haystack.deepset.ai

Reuse

Borrowing it

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

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 haystack AGENTS.md

README.md
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Your own site
<a href="https://agentmods.dev/instructions/deepset-ai/haystack/agents-md"><img src="https://agentmods.dev/badge/instructions/deepset-ai/haystack/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 haystack AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/deepset-ai/haystack/agents-md"><img src="https://agentmods.dev/badge/instructions/deepset-ai/haystack/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 1,897 This file is loaded in full into every session.
When invoked 1,897 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 $0.01897 $0.01897
Opus 5.5 $0.00759 $0.00759
Sonnet 5.5 $0.00379 $0.00379
Haiku 4.5 $0.00190 $0.00190

Measured 14d ago against content hash b1e032a3e6c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

haystack 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 14d 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 · 134 lines

How it starts

The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Haystack Guidelines for AI Agents

Environment

Haystack uses Hatch for environment and dependency management.

Do not run python or pip directly.

Before running code on this project, you must be able to run hatch --version and get a correct output.

If not, ask the user where Hatch is or if they want to install it. For installation instructions, refer to https://hatch.pypa.io/latest/install/#installation.

Run scripts with test dependencies

hatch -e test run python SCRIPT.py

Open a shell with test dependencies

hatch -e test shell

Install temporary dependencies (for experiments only)

uv pip install PACKAGE

Delete the environment

hatch env prune

Tests

Tests run via Hatch and support pytest arguments.

Prefer running tests on a specific module or using -k, since the full suite is large.

Run unit tests

hatch run test:unit

Run integration tests

hatch run test:integration

Quality Checks

Type checking with mypy

hatch run test:types

Type checking targets Python 3.12, above the 3.11 floor in requires-python, because numpy's stubs use PEP 695 type statements that mypy rejects below 3.12. So mypy will not catch code that breaks on 3.11; the unit test matrix runs on 3.11 and covers that.

To fix type issues, avoid type: ignore, casts, or assertions when possible. If they are necessary, explain why.

Format and lint

hatch run fmt

Release Notes

Every user-facing PR (not docs, not CI) must include a release note:

hatch run release-note SHORT_DESCRIPTION

Edit the generated file in releasenotes/notes/. Release notes use reStructuredText formatting; see the release notes section in CONTRIBUTING.md for details.

Pull Requests

Community contributors can have only one open pull request at a time in this repository. Before opening a PR on the user's behalf, check whether they already have one open (gh pr list --author @me); if so, tell them instead of opening another.

Read the full file on GitHub · 134 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. 14d ago Changed b1e032a3e6c8
  2. 21d ago Changed · +1 lines · +18 tokens per session 7277a5d84227
  3. 29d ago Changed · +4 lines · +56 tokens per session ff115aa204df
  4. 1mo ago Changed · +67 lines · +1,411 tokens per session e6281c53fc34
  5. 2mo ago First seen · 62 lines · 412 tokens per session scan A 95839b791fe9

Subscribe to this mod's changes

haystack AGENTS.md is an instructions file published in the GitHub repository deepset-ai/haystack (26,872 stars, last pushed today), licensed Apache-2.0. It adds 1,897 tokens to every session, about $0.0076 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.

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