# Setup > Verify context-budget's external prerequisites on this machine: `node`, which both the always-on settings-write checkpoint hook and the measurement engine depend on; the Claude Code CLI the engine measures against; and the optional Agent SDK that enables exact mode. Then report the effective settings-write-ask toggle. Use when: 'set up context-budget', 'configure context-budget', 'is context-budget working', 'why did the settings-write ask not prompt', 'why is the audit not exact', or an audit run reported a missing prerequisite. Check-only: verifies, reports, and points at each remediation; installs nothing and there is nothing setup may write here. Re-runnable and safe. - Skill: `melodic-software/setup-42` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add melodic-software/setup-42` - Raw SKILL.md: https://api.skillmd.com/api/skills/melodic-software/setup-42/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: melodic-software (https://skillmd.com/u/melodic-software) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/melodic-software/setup-42 --- ## 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: [`${CLAUDE_PLUGIN_ROOT}/skills/audit/SKILL.md`](../audit/SKILL.md) § Prerequisites and the header of `${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 `${user_config.settings_write_ask_enabled}` (an unexpanded token or an empty value means the manifest default `true`). INFO. The rendered value is injected when this skill loads, so a change made now is observed only in a **fresh session**; say so rather than re-reading it mid-session. When it reads `false`, note that the checkpoint is deliberately off and step 1's `node` finding downgrades to INFO for the hook (it stays FAIL for the engine). ## Remediation guidance (printed by `check`; the operator applies it) Every prerequisite here is a system tool or an operator install, and the one option lives in Claude Code's native configuration surface (Check-only carve-out, external-prerequisites and native-`userConfig` classes), so `check` closes by pointing at each resolution rather than writing. Re-running it after everything passes changes nothing and reports "already configured": - **Missing `node`:** the platform's own install channel (). This plugin never downloads a runtime. On Windows, confirm the hook's environment resolves the same `node` this check did. - **Missing CLI:** install the Claude Code CLI, or run the audit with an explicit `--binary` path. - **Exact mode wanted:** print this one-time install, marked as the operator's. It needs network access, so this skill offers it and never runs it: ```shell mkdir -p "${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 (, which owns the verified-version record): interactive `/plugin configure context-budget@` any time, or headless `claude plugin install context-budget@ -s --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.