farrier 1.4.0

Render an agent-neutral prompt library into a repository's Codex/Claude/Copilot adapters.

farrier

farrier renders an agent-neutral prompt library into a repository — generating the skill, prompt, instruction, and workflow adapters expected by Codex, Claude, and GitHub Copilot, plus the launcher scaffolding that runs them.

A farrier is the craftsman who fits the right gear onto each horse. This tool fits the shared prompt library onto each repository.

Install

pipx install farrier        # or: uv tool install farrier

farrier ships no library content of its own — the prompt library lives in a separate repository. Point farrier at it once:

farrier config set-library /path/to/vigilant-octo/agents
farrier config show

config writes a small TOML file in your OS config directory (~/.config/farrier/config.toml on Linux, ~/Library/Application Support/farrier/ on macOS, %APPDATA%\farrier\ on Windows).

Use

From a repository that has an agents.yml:

farrier --repo .            # render/install the selected packs
farrier --repo . --check    # verify generated files are up to date (no writes)

Rendering is the default action; farrier install --repo . is an accepted alias of farrier --repo ..

Configuring agents.yml

agents.yml (at your repo root) selects what farrier renders. Every option — repo, agents, packs, skills/prompts/roots, scaffolds, exclude, localInstructions, template/vars, and workflow — is documented with inline comments in agents.example.yml. Copy it to your repo as agents.yml and prune to taste.

Library layout

The other side of the contract is the agent library farrier renders from — what goes in library/skills/, library/prompts/, packs/, scaffolds/, and workflows/, the file formats expected, and how source names map to generated adapters. That is documented in docs/LAYOUT.md.

Locating the library

farrier resolves the library directory with this precedence:

1. --library DIR
2. $FARRIER_LIBRARY_DIR
3. library_dir from the home config (farrier config set-library)

If none resolve — or the path does not contain library/ and packs/ — farrier exits with a setup hint.

Related

• workhorse-agent — the fail-soft runtime that executes the workflows farrier installs. Both live in the stablemate workspace.