Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/virtuslab/orca/agents-mdgit clone --depth 1 https://github.com/VirtusLab/orcaWhat 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 | $0.05351 | $0.05351 |
| Opus 5 | $0.02676 | $0.02676 |
| Sonnet 5 | $0.01070 | $0.01070 |
| Haiku 4.5 | $0.00535 | $0.00535 |
Grade A, and why
orca AGENTS.md scanned grade A with 1 finding 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 2d 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.
Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
[`subprocess.QuietProc.call`](tools/src/main/scala/orca/subprocess/QuietProc.scala) How it starts
The opening of the file, as written. The whole thing — 379 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Working on Orca
Internals, architecture, and coding conventions for hacking on the library itself. Build/test commands and the recipes for running a locally modified orca live in CONTRIBUTING.md; end-user documentation in the README.
Orca is implemented in Scala 3 on top of Ox for structured concurrency, tapir for JSON Schema derivation, and jsoniter-scala for codec generation.
Project layout
orca/
├── build.sbt / project/
├── tools/ # tool traits + os-backed impls (git/gh/fs), LLM SPI + session durability, InStage, events, subprocess, sweep
├── flow/ # stage/display/fail + FlowContext/FlowControl; orca.{plan,review,pr,progress}
├── claude/ codex/ gemini/ opencode/ pi/ # one module per coding-agent backend
├── runner/ # flow() entry, DefaultFlowContext, FlowLifecycle, terminal UI
└── shell/ # `orca-shell`, the `orca` CLI's interactive front-end (ADR 0021)
Dependency graph:
tools (standalone)
├── flow → tools
├── claude / codex / gemini /
│ opencode / pi → tools
├── runner → tools + flow + all five backends
└── shell → runner (published `orca`)
The runner module owns the flow entry point (package orca) and wires
defaults via DefaultFlowContext (package orca.runner); the stage
setup/teardown/recovery state machine is orca.runner.FlowLifecycle. The
terminal UI lives in orca.runner.terminal, behind an Interaction, so
swapping it for a Slack or HTTP equivalent is one substitution at the call
site rather than rewiring modules.
The user-facing surface lives in package orca (the flow entry, the tool
accessors — including planningAgent/codingAgent/reviewAgent, the
backend-agnostic role accessors (ADR 0020) — stage/display/fail,
JsonData, OrcaArgs). Implementations live in
focused subpackages: orca.tools (os-backed git/gh/fs impls + their traits),
orca.agents + orca.backend (LLM SPI, SessionSupport,
conversation driver), orca.subprocess (subprocess shim), orca.sweep
(finds agent work that outlived a turn), orca.events
(event bus), one orca.tools.<backend> per coding agent, and orca.runner /
orca.runner.terminal (wiring + terminal UI). The flow module adds
orca.{plan,review,pr,progress}.
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.
- 2d ago First seen · 379 lines · 5,351 tokens per session scan A 4991af3af5e7
orca AGENTS.md is an instructions file published in the GitHub repository VirtusLab/orca (156 stars, last pushed 4d ago), licensed Apache-2.0. It adds 5,351 tokens to every session, about $0.0268 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
buildNext
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
spec-kit AGENTS.md
Instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
langchain AGENTS.md
Instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.