Hermes agent skill authoring
Skill percymcn/agent-cookbook/skills/software-development/hermes-agent-skill-authoring
Production-ready AI agent skills, playbooks, and workflows from the pharma6 automation lab
npx -y skills add percymcn/agent-cookbook --skill hermes-agent-skill-authoringAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
One thing to look at
- 0 stars0 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.
What its author says it does
Copied from the file, not written here
Author in-repo SKILL.md: frontmatter, validator, structure.
The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.
SKILL.md
7.4 KB, as published. Nobody here has run it
Authoring Hermes-Agent Skills (in-repo)
Overview
There are two places a SKILL.md can live:
- User-local:
~/.hermes/skills/<maybe-category>/<name>/SKILL.md— personal, not shared. Created viaskill_manage(action='create'). - In-repo (this skill is about this case):
/home/bb/hermes-agent/skills/<category>/<name>/SKILL.md— committed, shipped with the package. Usewrite_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
/home/bb/hermes-agent/skills/(usepatchfor small edits,write_filefor rewrites;skill_managestill works for patch on in-repo skills, but not forcreate)
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---\nbefore the body. - Parses as a YAML mapping.
namefield present.descriptionfield 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 <trigger>. <one-line behavior>.
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 intoreferences/*.mdand reference them from SKILL.md.
Peer-Matched Structure
Every in-repo skill follows roughly:
# <Title>
## Overview
One or two paragraphs: what and why.
## When to Use
- Bulleted triggers
- "Don't use for:" counter-triggers
## <Topic sections specific to the skill>
- Quick-reference tables are common
- Code blocks with exact commands
- Hermes-specific recipes (tests via scripts/run_tests.sh, 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/<category>/<skill-name>/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
- Survey peers in the target category:
Read 2-3 peer SKILL.md files to match tone and structure.ls skills/<category>/ - Check validator constraints in
tools/skill_manager_tool.pyif unsure. - Draft with
write_filetoskills/<category>/<name>/SKILL.md. - Validate locally:
import yaml, re, pathlib content = pathlib.Path("skills/<category>/<name>/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"]) <= 1024 assert len(content) <= 100_000 - Git add + commit on the active branch.
- Note: the CURRENT session's skill loader is cached —
skill_view/skills_listwill not see the new skill until a new session. This is expected, not a bug.
Cross-Referencing Other Skills
metadata.hermes.related_skills unions both trees (skills/ in-repo and ~/.hermes/skills/) at load time. You CAN reference a user-local skill from an in-repo skill, but it won't resolve for other users who clone the repo fresh. Prefer referencing only in-repo skills from in-repo skills. If a frequently-referenced skill lives only in ~/.hermes/skills/, consider promoting it to the repo.
Editing Existing In-Repo Skills
- Small fix (typo, added pitfall, tightened trigger):
skill_manage(action='patch', name=..., old_string=..., new_string=...)works fine on in-repo skills. - Major rewrite:
write_filethe whole SKILL.md.skill_manage(action='edit')also works but requires supplying the full new content. - Adding supporting files:
write_filetoskills/<category>/<name>/references/<file>.md,templates/<file>, orscripts/<file>.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
-
Using
skill_manage(action='create')for an in-repo skill. It writes to~/.hermes/skills/, not the repo tree. Usewrite_filefor in-repo creation. -
Leading whitespace before
---. The validator checkscontent.startswith("---"); any leading blank line or BOM fails validation. -
Description too generic. Peer descriptions start with "Use when ..." and describe the trigger class, not the one task. "Use when debugging X" > "Debug X".
-
Forgetting the author/license/metadata block. Not validator-enforced, but every peer has it; omitting makes the skill look half-finished.
-
Writing a skill that duplicates a peer. Before creating,
ls skills/<category>/and open 2-3 peers. Prefer extending an existing skill to creating a narrow sibling. -
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_viewusing the exact path. -
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/<category>/<name>/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_skillsreferences resolve in-repo (or are explicitly OK to be user-local) -
git add skills/<category>/<name>/ && git commitcompleted on the intended branch
Gives 0 of the 12 instructions most skill authoring skills give
Counted across 521 of the 523 authors here whose files we hold, read 2026-08-06
- keep skill files under 500 linesin 182 of 521, across 89 files
- use imperative form in instructionsin 101 of 521, across 30 files
- draft assertions while test runs are in progressin 88 of 521, across 22 files
- save test cases to evals jsonin 87 of 521, across 21 files
- create two to three realistic test promptsin 85 of 521, across 20 files
- write skill descriptions to be pushyin 84 of 521, across 19 files
- ask questions about edge cases and input formatsin 81 of 521, across 16 files
- save timing data immediately when runs completein 74 of 521, across 9 files
- include all trigger conditions in the skill descriptionin 73 of 521, across 7 files
- capture intent before writing a skillin 70 of 521, across 4 files
- launch all test runs in a single turnin 68 of 521, across 2 files
- write the description in third personin 56 of 521, across 19 files
Said here and by no other author read
- Place new skills in the in-repo skills directory
- Keep name under 64 characters using lowercase and hyphens
Grouped from the skills themselves: near-identical wordings counted once, and counted by distinct author, so one author publishing three of these counts once.