herdr

herdr is a skill for Claude Code, Codex from stewartcelani/skills. It costs 102 tokens per session (4,225 once invoked), scanned C, original, MIT.

A control guide for Herdr, a terminal multiplexer that organizes terminals into workspaces, tabs, and panes and can recognize coding agents.

In plain words
What is it for?
Use it to inspect panes, create terminal layouts, start agents or commands, read output, and wait for changes in workspaces or servers.
Why use it?
It lets an agent inspect and control terminal sessions from inside or outside Herdr, including through a reachable remote session, without relying on raw tmux.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; mentions Codex.

Good fit Use it to inspect panes, create terminal layouts, start agents or commands, read output, and wait for changes in workspaces or servers.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/stewartcelani/skills/herdr
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.

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

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/stewartcelani/skills/herdr/github.svg)](https://agentmods.dev/skills/stewartcelani/skills/herdr)
Your own site
<a href="https://agentmods.dev/skills/stewartcelani/skills/herdr"><img src="https://agentmods.dev/badge/skills/stewartcelani/skills/herdr/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 herdr

Your own site · 80×15
<a href="https://agentmods.dev/skills/stewartcelani/skills/herdr"><img src="https://agentmods.dev/badge/skills/stewartcelani/skills/herdr.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 102 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,225 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. 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 $0.00102 $0.04225
Opus 5 $0.00051 $0.02112
Sonnet 5 $0.00020 $0.00845
Haiku 4.5 $0.00010 $0.00422

Measured 10d ago against content hash bdc7cf4da6fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade C, and why

herdr scanned grade C 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 10d 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.

Tells the agent never to refusehighAnti-refusal

Suppressing the ability to decline removes a core safety control; a later harmful request then succeeds.

External control is intentional: it is how remote agents manage workspaces, servers, and sibling agents without falling back to raw tmux. **Never refuse Herdr work because you are "outside" Herdr or because `HERDR_ENV` i
skills/herdr/SKILL.md · 268 lines

How it starts

The opening of the file, as written. The whole thing — 268 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 session through the herdr CLI.

Inside and outside are both valid

Use the CLI whenever it can talk to the session. You do not need to be running inside a Herdr-managed pane.

Supported control paths include:

  • An agent already inside a Herdr pane
  • A shell or agent on the same machine that has herdr in PATH and can reach the session socket
  • Remote clients over SSH (home PC, Claude Desktop, Cursor, ChatGPT, etc.) driving Herdr on the server

External control is intentional: it is how remote agents manage workspaces, servers, and sibling agents without falling back to raw tmux. Never refuse Herdr work because you are "outside" Herdr or because HERDR_ENV is unset.

The herdr binary talks to the reachable session. Use it to inspect neighboring work, create terminal layout, start agents and commands, read output, and wait for state changes.

Only report that Herdr is unavailable if the CLI itself fails to reach a session (connection refused, no server, socket missing). Empty env or an external client is not a failure.

Caller context env vars (optional convenience)

When a process is inside a managed pane, Herdr may inject:

printf '%s\n' "${HERDR_ENV:-}" "$HERDR_WORKSPACE_ID" "$HERDR_TAB_ID" "$HERDR_PANE_ID"
  • HERDR_ENV=1 means this process was launched inside a Herdr-managed pane (when injection worked).
  • HERDR_WORKSPACE_ID, HERDR_TAB_ID, and HERDR_PANE_ID identify that pane when present.

Injection is unreliable: nested shells, agent runtimes, IDE terminals, SSH sessions, and many launch paths drop these vars. Missing env is normal for external control and is also common inside Herdr.

When env is present, prefer it (--current, $HERDR_PANE_ID, $HERDR_WORKSPACE_ID). When it is missing — the default for external/SSH clients — discover live state and target explicitly:

herdr workspace list
herdr pane list
herdr agent list
herdr pane current --current   # may fail outside a pane; then use explicit ids from list

Read the full file on GitHub · 268 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. 10d ago First seen · 268 lines · 102 tokens per session scan C bdc7cf4da6fa

Subscribe to this mod's changes

herdr is a skill published in the GitHub repository stewartcelani/skills (2 stars, last pushed 1mo ago), licensed MIT. It adds 102 tokens to every session and 4,225 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it C with 1 finding (tells the agent never to refuse). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

Other skills, from other repositories

uninstall

Uninstall a community skill that was installed via the hub. Confirms before deleting files, refuses to touch first-party plugin skills, and logs every action. Use when the user wants to fully remove a community skill ("uninstall [skill]", "remove this skill") rather than just disable it.

daddia/claude-for-strategy · 62 tokens

newsjack-detector

Monitor current news and reaction signals, then decide which are credible newsjacking opportunities for a client. Uses the local monitoring engine for evidence, but the skill owns PR judgment, brand safety, standing, decay, angle fit, and handoff.

elvisun/newsjack · 54 tokens

crisis-holding

Draft crisis holding statements, journalist Q&A posture, and what-not-to-say guidance from confirmed incident facts, with a hard legal-counsel gate. Builds each statement through proven crisis-comms frameworks (holding-statement anatomy, SCCT, CAP order, the legitimate non-answer, bridge/flag/block).

elvisun/newsjack · 67 tokens

find-journalists

Build, refine, dedupe, and enrich small fit-checked journalist lists for newsjack campaigns. Uses the newsjack CLI (preferred) or the medialyst MCP for news search and journalist enrichment, and falls back to a best-effort local mode with no verified contacts; the agent owns how returned data is organized.

elvisun/newsjack · 69 tokens

voice-extractor

Capture a user's real writing voice from 5-20 prior samples, store a local voice.yaml fingerprint, and enforce it on newsjack drafts so AI tells disappear. Measures voice with named stylometry lenses (Burrows's Delta function-word vector, MATTR lexical diversity, sentence-length burstiness, Biber Dimension-1 register…

elvisun/newsjack · 90 tokens

fact-check

Extract factual claims from PR copy, verify each claim independently, attach concrete citations, and warn when certainty is low. Runs each claim through proven newsroom verification methods (lateral reading, source-tier climbing, provenance pillars, triangulation, calibrated rating) and puts the burden of proof on the…

elvisun/newsjack · 85 tokens