mantis: Instructions file for Codex

AGENTS.md

mantis AGENTS.md is an instructions file for Codex, OpenCode from google/mantis. It costs 824 tokens per session, scanned A, original, Apache-2.0.

Repository-specific instructions for Mantis, including rules for formatting, protected text blocks, reference files, and extracting documentation.

In plain words
What is it for?
Use it before committing changes, editing fenced blocks, adding reference documents, or checking that documentation links and files are valid.
Why use it?
They prevent contributor changes from breaking required formatting, exact content, or linked documentation files.

Instructions file for CodexOpenCode ✓ vendor

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

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

About the project

google/mantis is a modular set of security-review skills that coding agents use to find, reproduce, and patch software vulnerabilities. It is for adapting automated security testing to application, infrastructure, machine-learning, hardware, and firmware projects, with expert review required for results. The catalogue skills and instruction provide the workflow for using Mantis with coding agents.

google/mantis · 2,563 stars · on GitHub · cloud.google.com

Reuse

Borrowing it

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

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 mantis AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/google/mantis/agents-md/github.svg)](https://agentmods.dev/instructions/google/mantis/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/google/mantis/agents-md"><img src="https://agentmods.dev/badge/instructions/google/mantis/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 mantis AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/google/mantis/agents-md"><img src="https://agentmods.dev/badge/instructions/google/mantis/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 824 This file is loaded in full into every session.
When invoked 824 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 $0.00824 $0.00824
Opus 5.5 $0.00330 $0.00330
Sonnet 5.5 $0.00165 $0.00165
Haiku 4.5 $0.00082 $0.00082

Measured 9d ago against content hash d6c46548011d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mantis 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 9d 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 · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Rules

Before committing

Always run pre-commit run --all-files before creating or amending a commit.

This ensures all markdown files conform to the pinned mdformat 0.7.21 formatter (--number --wrap 80 with gfm + frontmatter plugins). The hook installs its own isolated venv — do not run local mdformat directly.

If the hook modifies files, stage the changes and amend your commit.

ADK Invariant Architecture & Deterministic Gates

Security invariants (INV-1 through INV-6) are enforced deterministically by the Google ADK Python runtime, Pydantic schemas, and tool wrappers rather than prompt fences:

  • INV-1 & INV-2 (Evidence & Re-attack): Enforced by sandbox_tools.py reached-sink sentinel verification and schemas.py validation. Objective third-party re-attack and strict separation-of-duties role separation are orchestrated by mantis-patch to eliminate self-grading confirmation bias.
  • INV-3 (Regression Tracking): Enforced by finding lineage schemas and snapshot-match rules.
  • INV-4 (Target Immutability & Host Boundary): Enforced by research_tools.py path bounds checks (strictly read-only on the host target checkout; all mutations constrained to workspace/ or isolated guest sandboxes).
  • INV-5 (State Resumption & Monotonic Lineage): Enforced by BudgetController checkpointing and database.py monotonic status preservation across process restarts via --resume <run_id>. Upstream repository synchronization and environment provisioning are managed externally before resuming Mantis.
  • INV-6 (Fail-Safe Backward Compatibility): Enforced by schema defaults and fail-closed degradation gates.

Skills must remain clean, dense domain guides focused on vulnerability analysis, attack vectors, and remediation. Do not re-embed bash Git commands, manual file locking, or ASCII block fences in skill prompts. All invariants are verified by reference/tests/test_adk_invariants.py.

Reference files

Skills may split on-demand content into references/ subdirectories (e.g. skills/mantis-calibrate/references/calibration_rules.md). Before committing, verify that every references/*.md link target in a SKILL.md file exists on disk and is tracked by git (git ls-files --error-unmatch <path>).

Read the full file on GitHub · 74 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. 9d ago Changed · +2 tokens per session d6c46548011d
  2. 1mo ago Changed · +13 lines · +152 tokens per session a7801d362080
  3. 1mo ago First seen · 61 lines · 670 tokens per session scan A 1feb3a9510e2

Subscribe to this mod's changes

mantis AGENTS.md is an instructions file published in the GitHub repository google/mantis (2,563 stars, last pushed 2d ago), licensed Apache-2.0. It adds 824 tokens to every session, about $0.0033 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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