Setup

Purpose

Check-only setup under the Check-only carve-out (docs/PLUGIN-PHILOSOPHY.md "Setup is explicit and repeatable" in the marketplace repository): this plugin's configuration surface contains no writable artifact, so check inspects, reports, and points at each remediation, and no apply is offered because there is nothing it could conformingly write. The warrant is the carve-out's external-prerequisites class: node, the Claude Code CLI the engine pins and measures against, and the optional @anthropic-ai/claude-agent-sdk that enables exact mode, none of which a native configuration prompt can see, and each of which setup can only verify. The settings_write_ask_enabled option is a native userConfig toggle whose only stored home is the pluginConfigs this contract forbids setup to write.

Action routing: no argument or check runs the check. Non-interactive, never prompts.

check (read-only)

The audit skill and its engine are the single source of truth for what this plugin requires: ${CLAUDE_PLUGIN_ROOT}/skills/audit/SKILL.md § Prerequisites and the header of ${CLAUDE_PLUGIN_ROOT}/skills/audit/scripts/measure.mjs.

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.

Install nothing.

1. node on PATH. command -v node, and report the resolved path and version. This is the plugin's one hard prerequisite, and it carries two dependents. Report both:

   • The measurement engine is a Node script, so without node /context-budget:audit cannot produce a number and correctly stops rather than estimating.
   • The PreToolUse checkpoint in ${CLAUDE_PLUGIN_ROOT}/hooks/hooks.json registers in exec form, "command": "node" with the script in args, so Claude Code resolves the bare name node on PATH in the hook's own environment. A hook that fails to launch is non-blocking, so an unresolvable node means the checkpoint produces no ask and says nothing about it. That silent gap is exactly what a native configuration prompt cannot tell you: the option can read true while the hook it gates never runs.

   FAIL when absent. The checkpoint is a checkpoint either way, never a guarantee. A PermissionRequest hook can allow the call and disableAllHooks removes non-managed hooks.

2. The Claude Code CLI. command -v claude and its --version. The engine measures a pinned binary. PASS when one resolves; report the absolute path and version, because that stamp is what makes a report a claim. INFO when two installs are present. The audit asks which to pin. FAIL when none resolves and the operator has no --binary path to name, since the engine then has nothing to measure.

3. @anthropic-ai/claude-agent-sdk (optional). Probe whether it resolves under ${CLAUDE_PLUGIN_DATA}/sdk. Present: INFO, exact mode is available. Absent: INFO, not a defect. The engine degrades to parsing headless /context output (display-rounded, resting on an undocumented surface, and the record carries both caveats), and to a structured error rather than a wrong number when neither mode works.

4. Settings-write-ask toggle. Report the effective ${user_config.settings_write_ask_enabled} (an unexpanded token or an empty value means the manifest default true). INFO. The rendered value is injected when this skill loads, so a change made now is observed only in a fresh session; say so rather than re-reading it mid-session. When it reads false, note that the checkpoint is deliberately off and step 1's node finding downgrades to INFO for the hook (it stays FAIL for the engine).

Remediation guidance (printed by check; the operator applies it)

Every prerequisite here is a system tool or an operator install, and the one option lives in Claude Code's native configuration surface (Check-only carve-out, external-prerequisites and native-userConfig classes), so check closes by pointing at each resolution rather than writing. Re-running it after everything passes changes nothing and reports "already configured":

• Missing node: the platform's own install channel (https://nodejs.org/en/download). This plugin never downloads a runtime. On Windows, confirm the hook's environment resolves the same node this check did.

• Missing CLI: install the Claude Code CLI, or run the audit with an explicit --binary path.

• Exact mode wanted: print this one-time install, marked as the operator's. It needs network access, so this skill offers it and never runs it:

  mkdir -p "${CLAUDE_PLUGIN_DATA}/sdk" && npm install --prefix "${CLAUDE_PLUGIN_DATA}/sdk" @anthropic-ai/claude-agent-sdk
  

• Toggle off (or on): 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 context-budget@<marketplace> any time, or headless claude plugin install context-budget@<marketplace> -s <scope> --config settings_write_ask_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 token is injected at skill load, so a same-session check still reports the OLD value; report the observed effective value, never an unobserved change.

What this skill does NOT do

• Run a measurement, attribution, or ledger operation. That is /context-budget:audit.
• Install node, the CLI, or the Agent SDK. Guidance only.
• Write the plugin cache, Claude Code user settings, or pluginConfigs. Nor any other Claude Code settings surface.