Hermes Agent Skill Authoring

Authoring Hermes-Agent Skills (in-repo)

Overview

There are two places a SKILL.md can live:

1. User-local: ~/.hermes/skills///SKILL.md — personal, not shared. Created via skill_manage(action='create').
2. In-repo (this skill is about this case): /skills///SKILL.md — committed, shipped with the package. Use write_file + git add. skill_manage(action='create') does NOT target this tree.

When to Use

• User asks you to add a skill "in this branch / repo / commit"
• You're committing a reusable workflow that should ship with hermes-agent
• You're editing an existing skill under /skills/ (use patch for small edits, write_file for rewrites; skill_manage still works for patch on in-repo skills, but not for create)

Required Frontmatter

Source of truth: tools/skill_manager_tool.py::_validate_frontmatter. Hard requirements:

• Starts with --- as the first bytes (no leading blank line).
• Closes with \n---\n before the body.
• Parses as a YAML mapping.
• name field present.
• description field present, ≤ 1024 chars (MAX_DESCRIPTION_LENGTH).
• Non-empty body after the closing ---.

Peer-matched shape used by every skill under skills/software-development/:

---
name: my-skill-name # lowercase, hyphens, ≤64 chars (MAX_NAME_LENGTH)
description: Use when . .
version: 1.0.0
author: Hermes Agent
license: MIT
metadata:
 hermes:
 tags: [short, descriptive, tags]
 related_skills: [other-skill, another-skill]
---

version / author / license / metadata are NOT enforced by the validator, but every peer has them — omit and your skill sticks out.

Size Limits

• Description: ≤ 1024 chars (enforced).
• Full SKILL.md: ≤ 100,000 chars (enforced as MAX_SKILL_CONTENT_CHARS, ~36k tokens).
• Peer skills in software-development/ sit at 8-14k chars. Aim for that range. If you're pushing past 20k, split into references/*.md and reference them from SKILL.md.

Peer-Matched Structure

Every in-repo skill follows roughly:

# 

## Overview
One or two paragraphs: what and why.

## When to Use
- Bulleted triggers
- "Don't use for:" counter-triggers

## 
- Quick-reference tables are common
- Code blocks with exact commands
- Hermes-specific recipes (tests via scripts/run_tests.sh (user-local — verify it exists), ui-tui paths, etc.)

## Common Pitfalls
Numbered list of mistakes and their fixes.

## Verification Checklist
- [ ] Checkbox list of post-action verifications

## One-Shot Recipes (optional)
Named scenarios → concrete command sequences.

Not every section is mandatory, but Overview + When to Use + actionable body + pitfalls are the minimum for the skill to feel like a peer.

Directory Placement

skills///SKILL.md

Categories currently in repo (confirm with ls skills/): autonomous-ai-agents, creative, data-science, devops, dogfood, email, gaming, github, leisure, mcp, media, mlops/*, note-taking, productivity, red-teaming, research, smart-home, social-media, software-development.

Pick the closest existing category. Don't invent new top-level categories casually.

Workflow

1. Survey peers in the target category:

`` ls skills// `` Read 2-3 peer SKILL.md files to match tone and structure.

1. Check validator constraints in tools/skill_manager_tool.py if unsure.
2. Draft with write_file to skills///SKILL.md.
3. Validate locally:

``python import yaml, re, pathlib content = pathlib.Path("skills///SKILL.md").read_text() assert content.startswith("---") m = re.search(r'\n---\s*\n', content[3:]) fm = yaml.safe_load(content[3:m.start()+3]) assert "name" in fm and "description" in fm assert len(fm["description"]) //references/.md, templates/, or scripts/. skill_manage(action='write_file') also works and enforces the references/templates/scripts/assets subdir allowlist.

• Always commit the edit — in-repo skills are source, not runtime state.

Common Pitfalls

1. Using skill_manage(action='create') for an in-repo skill. It writes to ~/.hermes/skills/, not the repo tree. Use write_file for in-repo creation.

1. Leading whitespace before ---. The validator checks content.startswith("---"); any leading blank line or BOM fails validation.

1. Description too generic. Peer descriptions start with "Use when ..." and describe the trigger class, not the one task. "Use when debugging X" > "Debug X".

1. Forgetting the author/license/metadata block. Not validator-enforced, but every peer has it; omitting makes the skill look half-finished.

1. Writing a skill that duplicates a peer. Before creating, ls skills// and open 2-3 peers. Prefer extending an existing skill to creating a narrow sibling.

1. Expecting the current session to see the new skill. It won't. The skill loader is initialized at session start. Verify in a fresh session or via skill_view using the exact path.

1. Linking to skills that don't exist in-repo. related_skills: [some-user-local-skill] works for you but breaks for other clones. Prefer only in-repo links.

Verification Checklist

• [ ] File is at skills///SKILL.md (not in ~/.hermes/skills/)
• [ ] Frontmatter starts at byte 0 with ---, closes with \n---\n
• [ ] name, description, version, author, license, metadata.hermes.{tags, related_skills} all present
• [ ] Name ≤ 64 chars, lowercase + hyphens
• [ ] Description ≤ 1024 chars and starts with "Use when ..."
• [ ] Total file ≤ 100,000 chars (aim for 8-15k)
• [ ] Structure: # Title → ## Overview → ## When to Use → body → ## Common Pitfalls → ## Verification Checklist
• [ ] related_skills references resolve in-repo (or are explicitly OK to be user-local)
• [ ] git add skills/// && git commit completed on the intended branch

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: AtlasOmnia
• Source: AtlasOmnia/hermes-custom-pack
• License: MIT

Install and usage instructions live in the source repository linked above.