fix: self-install deps from script location, remove SessionStart hook

[hiskudin]

Summary

• Moves npm install from SessionStart hook into scan-tool-result.mjs itself, using import.meta.url to resolve the plugin root on disk
• Removes SessionStart hook from hooks/hooks.json entirely
• First-run install only happens when node_modules/@stackone/defender doesn't exist; subsequent invocations skip it via a synchronous existsSync check (essentially zero overhead)

Why

The SessionStart hook was unreliable: CLAUDE_PLUGIN_ROOT is not guaranteed to be set at that phase, so npm install would silently fail or install to the wrong directory. Moving install into the scan script itself means it uses a path derived from import.meta.url — always correct regardless of env vars.

Test plan

• Fresh install: delete node_modules/@stackone/defender, trigger a tool call (e.g. Bash echo hi) — defender installs automatically and scan runs
• Subsequent calls: existsSync returns true, install is skipped, scan is near-instant
• Injection content in WebFetch response: blocked with exit 2

🤖 Generated with Claude Code

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Summary by cubic

Self-install plugin deps from the scan script using its own path (no env var) and expand scanning to MCP tool responses; warn on install failures. Also remove the SessionStart hook so @stackone/defender installs on first scan only.

• Bug Fixes

  • Resolve plugin root via import.meta.url; drop CLAUDE_PLUGIN_ROOT.
  • First-run self-install via npm install --prefix "<pluginRoot>" --silent --no-audit --no-fund (120s timeout); on failure, emit stderr warning and skip scan (exit 0); no SessionStart hook.
  • Scan MCP tool outputs using raw.result/raw.output or JSON.stringify(raw) (try/catch), and log serialization errors to stderr to avoid silent skips.

• Dependencies

  • Switch release-please to the node release type.

^{Written for commit 95d91a3. Summary will update on new commits.}

[Copilot]

Pull request overview

This PR makes the Defender dependency installation self-contained within the PostToolUse scanner script, removing the previously unreliable SessionStart hook-based install step.

Changes:

• Add first-run dependency self-install logic to scripts/scan-tool-result.mjs by resolving the plugin root from the script location.
• Remove the SessionStart hook from hooks/hooks.json so installs no longer happen during session initialization.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
scripts/scan-tool-result.mjs	Resolves plugin root, self-installs dependencies on first run, and then loads @stackone/defender via createRequire.
hooks/hooks.json	Removes the SessionStart hook that previously ran npm install.

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[cubic-dev-ai]

1 issue found across 1 file (changes from recent commits).

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="scripts/scan-tool-result.mjs">

<violation number="1" location="scripts/scan-tool-result.mjs:55">
P2: `JSON.stringify(raw)` on arbitrary objects can throw (e.g., circular refs/BigInt), which can crash the hook before scan handling.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

2 issues found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="scripts/scan-tool-result.mjs">

<violation number="1" location="scripts/scan-tool-result.mjs:21">
P1: Avoid trusting `CLAUDE_PLUGIN_ROOT` for plugin root resolution here; prefer the script-derived path so install/load cannot be redirected by environment tampering.</violation>

<violation number="2" location="scripts/scan-tool-result.mjs:33">
P2: On install failure the script exits 0 with no output, silently disabling the entire tool-output scanner. At minimum emit a warning to stderr so users can diagnose why Defender isn't running.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

0 issues found across 2 files (changes from recent commits).

_{Requires human review: Changes to dependency installation (moving npm install to the script runtime) and removing the SessionStart hook modify the plugin's lifecycle and warrant human review.}

[cubic-dev-ai]

0 issues found across 1 file (changes from recent commits).

_{Requires human review: Modifies CI/CD release configuration, changes hook architecture, and introduces runtime dependency installation and new serialization logic for security scanning.}