herdr

A workflow for controlling Herdr, a terminal multiplexer that organizes coding-agent sessions into workspaces, tabs, and panes. It can inspect sessions and, when allowed, control terminals or agents.

In plain words
What is it for?
Use it to inspect panes, tabs, workspaces, commands, or other agents in Herdr, provided the current agent is running inside Herdr.
Why use it?
It helps an agent work with an existing Herdr session without confusing an ordinary terminal for a Herdr-managed pane.

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

Made for: Claude Code, Codex.

Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,328 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00074 $0.02328
Opus 5 $0.00037 $0.01164
Sonnet 5 $0.00015 $0.00466
Haiku 4.5 $0.00007 $0.00233

Measured yesterday against content hash 237ad2ab2d81, 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 yesterday.

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

Copies of this mod

6 near-identical copies found in the catalogue:

  • herdr — 97% identical, 4 lines differ
  • herdr — 97% identical, 4 lines differ
  • herdr — 97% identical, 4 lines differ
  • herdr — 95% identical, 29 lines differ
  • herdr — 89% identical, 6 lines differ
  • herdr — 89% identical, 27 lines differ
skills/herdr/SKILL.md · 196 lines

How it starts

The opening of the file, as written. The whole thing — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Herdr

Herdr organizes terminals into workspaces, tabs, and panes, recognizes 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 organize terminal locations.
  • Pane commands control raw terminals, shells, tests, servers, input, and output.
  • Agent commands control the recognized 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 · 196 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. yesterday First seen · 196 lines · 74 tokens per session scan A 237ad2ab2d81

Subscribe to this mod's changes

herdr is a skill published in the GitHub repository herdrdev/herdr (33,954 stars, last pushed today), licensed Apache-2.0. It adds 74 tokens to every session and 2,328 once invoked, about $0.0004 per session on Opus 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.