# Setup

> Configure the toolchain plugin for this repository. check (read-only): report which ecosystems are configured and each one's resolved build/test/lint command surface, validating the tracked files against the contract schema. apply: interview the user, infer per-ecosystem commands from the repo layout, and write the tracked .claude/ecosystems/<ecosystem>.yaml files that /toolchain:check and /toolchain:lint resolve first. Use when: 'set up toolchain', 'configure build/lint commands', 'toolchain setup', /toolchain:check or /toolchain:lint reports it is falling back to bundled defaults, or a toolchain change needs recording. Actions: check (read-only verification, default) | apply (write the ecosystem command config). Re-runnable and safe.

- Skill: `melodic-software/setup-15` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add melodic-software/setup-15`
- Raw SKILL.md: https://api.skillmd.com/api/skills/melodic-software/setup-15/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Docs & Writing
- Author: melodic-software (https://skillmd.com/u/melodic-software)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/melodic-software/setup-15

---


## Purpose

Inspect and configure the consuming repo's tracked ecosystem command surface per the uniform setup
contract (`docs/PLUGIN-PHILOSOPHY.md` "Setup is explicit and repeatable" in the marketplace
repository): `check` reports what is configured, `apply` writes it. The tracked files at
`.claude/ecosystems/<ecosystem>.yaml` let `/toolchain:check` and `/toolchain:lint` resolve commands
deterministically from rung 1 of the ladder
([`${CLAUDE_PLUGIN_ROOT}/reference/resolution-ladder.md`](${CLAUDE_PLUGIN_ROOT}/reference/resolution-ladder.md))
instead of inferring or falling back to bundled defaults every run. This skill is the ladder's
**writer** for rungs 2 and 3 (infer-and-persist, ask-and-persist).

Idempotent: re-running reads the existing files and offers updates rather than overwriting blind. The
plugin ships working bundled portable defaults (rung 4), so an unconfigured ecosystem is **INFO** (the
default resolves), never FAIL.

Action routing: no argument or `check` runs the check; `apply` runs the check first, then writes.
`apply <ecosystem>` scopes the whole run to that one ecosystem; when a named ecosystem's inference is
unambiguous it is written non-interactively, otherwise (or with no ecosystem argument in an
interactive session) the interview below runs.

### Resolve repo root

```bash
REPO_ROOT=$(git rev-parse --show-toplevel)
```

Read and write only inside `$REPO_ROOT/.claude/`, never the plugin directory or the plugin data
directory; configuration lives in the consumer's tracked files.

## `check` (read-only)

The bundled portable defaults and the contract schema are the single source of truth for the file
shape (`${CLAUDE_PLUGIN_ROOT}/reference/ecosystems/`, `ecosystem.schema.json`). **Read the ladder
first**, then report a PASS/FAIL/INFO table; modify nothing.

1. **Configured ecosystems.** For each `$REPO_ROOT/.claude/ecosystems/<ecosystem>.yaml` present,
   report the ecosystem and its resolved command surface
   (`build-cmd`/`test-cmd`/`check-cmd`/`fix-cmd`/`code-fix-cmd`). Validate each against the contract's
   `ecosystem.schema.json`. **FAIL** a schema-invalid file (with the validation error in the
   remediation line), an ecosystem file excluded by `.gitignore` (`git check-ignore -v` matches;
   teammates would never receive it. Report the matching rule), or an un-ignored but untracked file
   (`git ls-files --error-unmatch` exits non-zero; report "commit it to share with the team").
   Otherwise PASS. If `$ARGUMENTS` names one ecosystem, scope
   the report to just that file.
2. **Unconfigured ecosystems.** INFO: detect which ecosystems the repo has that are *not* yet
   configured (see the inference signals under `apply`), and note that `/toolchain:check` /
   `/toolchain:lint` resolve those through inference then the bundled portable defaults. The
   remediation is `apply` to persist a command surface.

## `apply` (idempotent)

Run `check` first. Then write the accepted ecosystem files. After each write, re-run the `check`
probe pair for that path rather than trusting the write: `git check-ignore -v` reports no match,
and `git ls-files --error-unmatch` distinguishes tracked from written-but-untracked (the
guaranteed state right after a fresh write — report "written but untracked: commit it", never
success).

### 1. Read existing config first

For each `$REPO_ROOT/.claude/ecosystems/<ecosystem>.yaml` that already exists, load it and present a
short summary. The interview proposes changes against that baseline; nothing is dropped without the
user confirming. If `$ARGUMENTS` names one ecosystem, scope the whole run to just that file.

### 2. Infer candidates from the repo before asking

Detect which ecosystems apply from what actually exists, and draft each one's command surface. Seed
the draft from the bundled portable default at
[`${CLAUDE_PLUGIN_ROOT}/reference/ecosystems/<ecosystem>.yaml`](${CLAUDE_PLUGIN_ROOT}/reference/ecosystems/),
then specialize it to the repo:

- **dotnet**. `*.slnx`/`*.sln`/`*.csproj` present. Resolve the `anchor` (solution file at root, else
  nearest project). Note any repo-specific trap in `notes` (e.g. the xUnit v3 `--nologo` pin).
- **python**. `pyproject.toml`/`uv.lock`. Prefer `uv run …` when `uv.lock` exists, else plain
  `ruff`/`pytest`. Set `project-discovery` to the `pyproject.toml` roots.
- **typescript**. `package.json`/`tsconfig*.json`. Read the `scripts` block for the real `test-cmd`;
  pick `check-cmd`/`fix-cmd` (format-only) and `code-fix-cmd` (semantic lint autofixes) from the
  configured linter (`biome.json` → Biome format vs check --write; eslint config → ESLint).
- **bash** / **powershell**. Shell/PowerShell files present; keep the bundled check/fix commands
  unless the repo documents its own.
- **markdown**, a markdownlint config present.
- **yaml**. `.github/workflows/` present (lint-only surface. `/toolchain:lint` runs it,
  `/toolchain:check` does not).
- **cross-cutting**. Repo-root config for `typos`/`gitleaks`/`editorconfig-checker`/`lychee-offline` present (lint-only).

Repo-specific CI-parity gates beyond plain build/test/lint (lockfile drift, generated-artifact
freshness, schema regeneration) belong in the ecosystem file's `gates` array. Draft one when the
repo's CI runs such a check. For an ecosystem with `project-discovery`, a gate that is repo-wide
rather than per-project (protobuf generation, schema freshness. Checks something that exists once,
not once per discovered project root) needs `run-from: repo-root` on the drafted gate; omitting it
defaults to per-project execution, which redundantly re-runs the check in every root or fails in
roots lacking its config. Ask which shape applies when the CI check's own scope is ambiguous from its
command alone.

### 3. Interview or write non-interactively

When `apply <ecosystem>` names one ecosystem and its inference is unambiguous, write the drafted
command surface non-interactively. Otherwise interview, one decision at a time: present each inferred
ecosystem's drafted command surface with a recommendation; let the user accept, edit, or skip it. When
inference is ambiguous (multiple test runners, no configured linter), ask for the command rather than
guessing. Offer any ecosystem the repo has that inference missed.

### 4. Write the files

Materialize one `$REPO_ROOT/.claude/ecosystems/<ecosystem>.yaml` per accepted ecosystem, conforming to
the contract's `ecosystem.schema.json`. Each file carries a one-line header comment citing the
contract, `globs` (required), the four command keys (`null` where a phase does not apply), and the
optional keys that apply (`anchor`, `project-discovery`, `opt-in`, `install-hint`, `gates`, `notes`).
Confirm each file is tracked, not ignored.

Recommend the consumer validate these in their own gate, a `check-jsonschema` hook or CI lane against
the contract schema catches typos the tolerant reader would otherwise ignore.

### 5. Offer the overlay convention

Personal per-key overrides go in `.claude/ecosystems/<ecosystem>.local.yaml`; a user-global base at
`~/.claude/ecosystems/<ecosystem>.yaml` is also honored. Layers resolve
user-global → team → local overlay, additively per key. Recommend the consumer add the recursive
`.claude/**/*.local.*` line to `.gitignore` if not already covered.

## Output

Tracked `.claude/ecosystems/*.yaml` files in the consuming repo, and a one-paragraph summary of what
was written and how to re-run this setup to reconfigure. `check` alone reports the effective
configuration and changes nothing.

## What this skill does NOT do

- Run build/test/lint. That is `/toolchain:check` and `/toolchain:lint`.
- Write machine-local state. Configuration lives in the consumer's tracked files, never in the plugin
  directory or the plugin data directory.
- Write the plugin cache, Claude Code user settings, or `pluginConfigs`.
- Ship or edit the bundled portable defaults. Those are the plugin's rung-4 fallback, never written
  into a consumer repo except as the seed for a file this interview produces.