Setup

Purpose

Thin check-centric setup per the uniform setup contract (docs/PLUGIN-PHILOSOPHY.md "Setup is explicit and repeatable" in the marketplace repository): check inspects and reports, apply resolves. This plugin owns no consumer-project configuration. actionlint auto-discovers its own optional config from the repository, and the tunables are the native userConfig options (the actionlint_enabled toggle and stdin_read_timeout). Every prerequisite is a PATH binary the plugin never bundles, and the plugin never installs system packages, so apply is guidance-only with no write path. It never modifies the repository, user settings, or the plugin cache.

Action routing: no argument or check runs the check; apply runs the check first, then offers remediation guidance. Both are non-interactive. Never prompt when the action is given.

check (read-only)

The hook script (${CLAUDE_PLUGIN_ROOT}/hooks/actionlint-check.sh) is the single source of truth for what it requires and how it resolves things.

Read it first. Probe what it actually does, don't recite this file. Then run each probe via Bash and report a PASS/FAIL/INFO table with one remediation line per FAIL. Do not modify anything.

When the plugin's toggle is disabled, every prerequisite absence downgrades from FAIL to INFO. The hook exits through its enabled-gate before probing anything, so a deliberately disabled plugin is not broken. Report the probes informationally and note that re-enabling restores the FAIL semantics.

1. Bash version. Check against the hook's documented floor (README Requirements), noting any features the hook degrades without (for example telemetry's EPOCHREALTIME, a Bash 5.0+ builtin).
2. jq. command -v jq. FAIL if absent: the hook then skips with a visible once-per-session notice instead of linting.
3. actionlint. command -v actionlint. FAIL if absent: the hook skips workflow lint with a visible once-per-session notice (it ships no binary of its own).
4. actionlint config. INFO: actionlint auto-discovers an optional .github/actionlint.yaml from the repository when present. It is not required. actionlint runs with its built-in defaults without one. Report whether one exists for the reader's awareness; its absence is not a FAIL.
5. Hook toggle. Report the effective actionlint_enabled value: ${user_config.actionlint_enabled} (unexpanded or empty means default true; any value other than true disables the hook). 5b. Stdin read timeout. INFO: report the effective stdin_read_timeout value: ${user_config.stdin_read_timeout} (unexpanded or empty means default 2 seconds, minimum 1). It is an IDLE bound. Any byte arriving resets it, so it fires only once the pipe has gone silent for that long, at which point this hook fails open. A value read -t will not accept, or 0, falls back to the default.
6. Hook registration. INFO: confirm the plugin is enabled for this project (/plugin → Installed) rather than parsing settings files.

apply (idempotent)

Run check, then for each FAIL point at the resolution. This skill installs nothing:

• missing actionlint: platform install guidance from the README Requirements section (the actionlint install guide).
• missing jq / Bash: platform install instructions from the README Requirements section.
• toggle off: reconfigure through Claude Code's native flow, per the marketplace's plugin-reconfiguration convention (https://github.com/melodic-software/claude-code-plugins/blob/main/docs/conventions/plugin-reconfiguration/README.md, which owns the verified-version record): interactive /plugin configure actionlint@<marketplace> any time, or headless claude plugin install actionlint@<marketplace> -s <scope> --config actionlint_enabled=true (repeatable per key) — against an already-installed plugin it prints already installed and still writes the value. Do not uninstall to reconfigure: that drops this plugin's entire stored pluginConfigs entry, resetting every option in the README's Options reference to its manifest default. -s defaults to user; pass the scope claude plugin list reports for this plugin, and run from that project's directory for a project/local scope, or the write lands at a scope that does not load. This skill never writes user settings or pluginConfigs. Afterwards rerun check in a fresh session — the rendered ${user_config.*} is injected at skill load and each hook receives its CLAUDE_PLUGIN_OPTION_* from an environment fixed at session start, so a same-session check still reports the OLD value; report the observed effective value, never an unobserved change.

After pointing at a remediation, re-run the relevant check probe and report its actual result. Never claim resolved on the reader's report that they installed something.

Re-running apply after everything passes changes nothing and reports "already configured".

Gotchas

• A userConfig knob is reachable natively only if the manifest declares it. Per current docs, claude plugin install --config <key=value> sets options "declared in the plugin's manifest". An undeclared key silently cannot be set through native config surfaces (a raw settings env block still works). That is why stdin_read_timeout is declared in this plugin's manifest even though the shared hook lib supplies its default; hook plugins reusing the shared lib should declare it too.
• --config's post-install behavior is undocumented, so the guidance above rests on observation. The official docs describe --config only as a claude plugin install flag and say nothing about an already-installed plugin. The verified-version record — which CLI release the still-writes claim was observed on, and which conditions it covered — lives only in the plugin-reconfiguration convention cited in apply above.
• -shellcheck= / -pyflakes= are deliberate, and the deadlock claim is a local observation. The hook disables actionlint's external run-block linters primarily for edit-time latency; the additional "ShellCheck deadlocks on large blocks under the Windows subprocess IPC path in actionlint 1.7.x" rationale is the hook author's own reproduction. No matching upstream rhysd/actionlint issue as of 2026-07-23. The latency rationale alone justifies the flags for an advisory edit-time hook; deep run-block linting belongs in a commit hook or CI.

What this skill does NOT do

• Run the linter. Editing any .github/workflows/*.yml or *.yaml file exercises the hook end-to-end.
• Write the plugin cache, Claude Code user settings, or pluginConfigs. Nor the repository. Every prerequisite is a PATH binary or the native toggle, so remediation is guidance only.
• Download or execute tools during check beyond the read-only command -v presence probes.