herdr is a background runtime that keeps coding-agent terminals and sessions running, even when a computer disconnects or restarts. It lets people and agents manage, inspect, and reconnect to sessions through a terminal interface or SSH while using tools such as Claude Code and Codex. The catalogue add-ons extend its panes and workflows.
Borrowing it
Nothing to install: this file belongs to herdrdev/herdr. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/herdrdev/herdr/master/AGENTS.mdgit clone --depth 1 https://github.com/herdrdev/herdrWrote 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.
[](https://agentmods.dev/instructions/herdrdev/herdr/agents-md)<a href="https://agentmods.dev/instructions/herdrdev/herdr/agents-md"><img src="https://agentmods.dev/badge/instructions/herdrdev/herdr/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.
<a href="https://agentmods.dev/instructions/herdrdev/herdr/agents-md"><img src="https://agentmods.dev/badge/instructions/herdrdev/herdr/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.06363 | $0.06363 |
| Opus 5.5 | $0.02545 | $0.02545 |
| Sonnet 5.5 | $0.01273 | $0.01273 |
| Haiku 4.5 | $0.00636 | $0.00636 |
Grade A, and why
herdr 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 27d 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.
How it starts
The opening of the file, as written. The whole thing — 330 lines — stays where its author put it; the contents beside it link to each section on GitHub.
herdr
Terminal based agent runtime for coding agents.
Scope and Audience
These instructions are layered.
- Unless a section explicitly says it is maintainer-only, local-machine-only, or external-contributor-only, treat it as universal project guidance.
- Universal project rules apply to every agent working on Herdr, including forks.
- Maintainer accounts are listed in
.github/MAINTAINERS. Treat the acting account as a verified maintainer only when its username is listed there, the configured remote is the canonicalherdrdev/herdrrepository, and the authenticated account has write access to that repository. If any condition cannot be verified, skip maintainer workflow and follow the external contributor guardrail instead. - Local Can machine workflow applies only on Can's own workstation or Windows
VM setup, for example when
/home/can/Projects/herdr,HERDR_ENV=1, or thewindows-wirtSSH alias exists. If those facts are not true, skip local machine workflow. - External contributor guardrail applies whenever the acting GitHub account is not a verified maintainer, the work is happening in a fork, or the account cannot be determined.
Universal Project Rules
Principles
- State is separated from runtime.
AppStateis pure data, testable without PTYs or async.PaneStateis separate fromPaneRuntime. Workspace logic doesn't need real terminals. - Render is pure.
compute_view()handles geometry and mutations.render()takes&AppStateand only draws. Never mutate state during render. - No god objects. If a module is doing too many things, split it.
app/is already split into state, actions, and input. Keep it that way. - Platform code is isolated. OS-specific behavior lives in the matching
src/platform/<os>.rsfile, with only shared traits, types, wrappers, and testable contracts insrc/platform/mod.rs. Core modules don't have#[cfg(target_os)]. - Detection is decoupled. The detector reads a screen snapshot, never touches the parser or viewport state.
- Screen detection is evidence-based. When changing
src/detect/manifests/, first capture the relevant bottom-buffer state withherdr agent read <pane> --source detection --format textand, when styling or alternate screen behavior matters,--format ansi. Decide which visible controls are invariant, which are alternatives, and encode them as explicit AND/OR gates. Do not match whole-pane incidental text, and do not use the user-visible viewport for agent status because users can scroll it. - UI patterns should be reused. Herdr is a mouse-first TUI. New dialogs, onboarding, settings, and post-update flows should follow the existing UI/UX language and interaction patterns instead of inventing one-off screens. Prefer reusing existing modal/screen structure, affordances, and close actions so the app feels consistent.
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.
- 27d ago Changed · +18 tokens per session 0a95710c61ac
- 1mo ago Changed · +2 lines · +127 tokens per session 684ed8d3164a
- 1mo ago Changed · +10 lines · +590 tokens per session 4a46d8150578
- 1mo ago Changed · +12 lines · +176 tokens per session c2eca9d5147a
- 1mo ago Changed · +15 lines · +467 tokens per session 7739d25aa928
- 1mo ago First seen · 291 lines · 4,985 tokens per session scan A 27d2768d62b9
herdr AGENTS.md is an instructions file published in the GitHub repository herdrdev/herdr (46,030 stars, last pushed today), licensed Apache-2.0. It adds 6,363 tokens to every session, about $0.0255 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
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
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, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
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.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.