Claude pack: plugin.json "hooks": "./hooks/hooks.json" makes Claude Code ≥2.1.255 refuse the whole plugin (Duplicate hooks file) #462

Summary

packages/agent-bundle/src/adapters/claude.ts (buildPluginManifest, around line 3164) writes

...(hookDocument === undefined ? {} : { hooks: `./${hookContract.manifestPath}` }),

into .claude-plugin/plugin.json, i.e. "hooks": "./hooks/hooks.json". Claude Code auto-loads the conventional hooks/hooks.json, and since 2.1.255 it treats the manifest entry as a duplicate and refuses to load the plugin at all:

Hook load failed: Duplicate hooks file detected: ./hooks/hooks.json resolves to already-loaded file
<root>/hooks/hooks.json. The standard hooks/hooks.json is loaded automatically, so manifest.hooks
should only reference additional hook files.

Observed with Claude Code 2.1.259 on cargo-hauler@0.4.1 built from agent-bundle preview 886b192: claude plugin list shows ✘ failed to load; the session has no mcp__cargo-hauler__* tools and none of the plugin's hooks, even though agent-bundle doctor --host claude reports installed copy: current. Downstream report: ScriptedAlchemy/cargo-hauler#48.

Fix

• Omit hooks from plugin.json when the hook manifest is at the conventional hooks/hooks.json (which is always the case for the adapter's own output). Only emit hooks for additional hook files.
• native-claude-contract / doctor --host claude should run claude plugin list --json and surface errors[] for the installed plugin, reporting it broken rather than current.
• Add the 2.1.255+ behaviour to the Claude capability table / audit notes so the contract test catches a regression.

Version

agent-bundle 886b192 (main); main at 284141958 still has the same line.