herdr

herdr is a skill for Claude Code, Codex from sammcj/agentic-coding. It costs 29 tokens per session (2,344 once invoked), scanned A, a copy of herdr, Apache-2.0.

A tool for managing Herdr, a terminal multiplexer that arranges coding agents and commands in workspaces, tabs, and panes. It can inspect the current Herdr session from the command line.

In plain words
What is it for?
Inspecting Herdr workspaces, panes, tabs, agents, terminals, and worktrees, or creating and controlling parts of a Herdr session.
Why use it?
It helps organise several terminal-based coding tasks and makes it easier to see or control related agents and commands in one session.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/sammcj/agentic-coding/herdr
Any agent
npx skills add sammcj/agentic-coding --skill herdr
Clone the repo
git clone --depth 1 https://github.com/sammcj/agentic-coding

Made for: Claude Code, Codex.

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 herdr

README.md
[![agentmods](https://agentmods.dev/badge/skills/sammcj/agentic-coding/herdr.svg)](https://agentmods.dev/skills/sammcj/agentic-coding/herdr)
Your own site
<a href="https://agentmods.dev/skills/sammcj/agentic-coding/herdr"><img src="https://agentmods.dev/badge/skills/sammcj/agentic-coding/herdr.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,344 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 91% copy Near-identical to another mod 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 $0.00029 $0.02344
Opus 5 $0.00015 $0.01172
Sonnet 5 $0.00006 $0.00469
Haiku 4.5 $0.00003 $0.00234

Measured 2d ago against content hash 9fce07ccade6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

herdr 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 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.

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.

Origin

This is a copy

91% identical to herdr — 14 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

Skills/herdr/SKILL.md · 200 lines

How it starts

The opening of the file, as written. The whole thing — 200 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Herdr

Herdr organises terminals into workspaces, tabs, and panes, recognises coding agents running inside panes, and exposes the current session through the herdr CLI.

Before issuing any control command, verify that this agent is running inside a Herdr-managed pane:

test "${HERDR_ENV:-}" = 1

If the check fails, say that you are not running inside Herdr and stop. Do not inspect or control the focused Herdr session from outside Herdr.

When the check passes, the herdr binary in PATH talks to the current session. Use it to inspect neighboring work, create terminal layout, start agents and commands, read output, and wait for state changes.

Learn the current CLI

The installed binary is the authority for command syntax. Start with:

herdr --help

Then print the relevant command group by running the group without a subcommand:

herdr agent
herdr pane
herdr workspace
herdr tab
herdr worktree
herdr terminal
herdr notification
herdr integration
herdr session

Do not run bare herdr for discovery; it launches or attaches the TUI. Do not probe a mutating nested command by omitting arguments. Commands such as herdr workspace create are valid with defaults and will execute.

Most control commands return JSON. Read identifiers and state from those responses instead of predicting them.

Understand layout, panes, and agents

Choose the primitive that matches the job:

  • Workspace, tab, and pane topology organise terminal locations.
  • Pane commands control raw terminals, shells, tests, servers, input, and output.
  • Agent commands control the recognised coding agent currently occupying a pane.

A pane exists whether or not it contains an agent. agent start requires an existing available shell pane and never creates, splits, or moves layout. Use pane commands for ordinary processes. Use agent commands when Herdr must validate agent identity or interpret idle, working, blocked, done, and unknown lifecycle states.

Agent commands accept either a unique live agent name or the pane ID currently hosting that agent. They do not accept terminal IDs or bare agent-kind labels. Names must match [a-z][a-z0-9_-]{0,31} and be unique among live agents. A name follows the current pane occupant and is cleared when that agent exits, is released, or is replaced.

Read the full file on GitHub · 200 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. 2d ago First seen · 200 lines · 29 tokens per session scan A 9fce07ccade6

Subscribe to this mod's changes

herdr is a skill published in the GitHub repository sammcj/agentic-coding (159 stars, last pushed yesterday), licensed Apache-2.0. It adds 29 tokens to every session and 2,344 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to herdr, differing in 14 lines, and is treated as a copy.

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