Plugin hooks fire twice: marketplace source + cache both loaded

[pitimon]

Description

Plugin hooks fire twice for every event (SessionStart, UserPromptSubmit, PostToolUse, Stop) because Claude Code loads hooks from both the marketplace source directory and the installed cache directory.

Steps to Reproduce

1. Install a plugin that has hooks:

   claude plugin marketplace add thedotmack
   claude plugin install claude-mem@thedotmack

2. Start a new Claude Code session

3. Observe that SessionStart and UserPromptSubmit hook messages appear twice in system reminders

Root Cause

After installation, the same hooks.json exists in two locations:

~/.claude/plugins/marketplaces/thedotmack/plugin/hooks/hooks.json   ← marketplace source
~/.claude/plugins/cache/thedotmack/claude-mem/9.0.17/hooks/hooks.json ← installed cache

Both files are identical. Claude Code loads hooks from both paths, causing every hook to execute twice.

Expected Behavior

Claude Code should load hooks only from the installed cache (cache/), not from the marketplace source directory (marketplaces/). The marketplace directory should only serve as a source for plugin install, not as an active hook source.

Workaround

Rename the hooks.json in the marketplace source:

mv ~/.claude/plugins/marketplaces/<marketplace>/plugin/hooks/hooks.json \
   ~/.claude/plugins/marketplaces/<marketplace>/plugin/hooks/hooks.json.bak

Note: This workaround is fragile — running marketplace add again will restore the file.

Environment

• Claude Code (latest as of 2026-02-08)
• macOS (Darwin 25.2.0)
• Affected plugin: claude-mem@thedotmack (any plugin with hooks would be affected)

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Plugin cache keeps old versions and runs their hooks! #15621
2. [BUG] SessionStart hooks invoked twice per session causing race conditions #14937
3. [BUG] Plugin-registered hooks are executed twice with different PIDs #10871

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
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🤖 Generated with Claude Code

[pitimon]

This is not a duplicate of the suggested issues. Let me clarify:

• [BUG] Plugin-registered hooks are executed twice with different PIDs #10871 was closed as not_planned (auto-closed by bot) despite being assigned to @dhollman — the bug was never actually fixed
• [BUG] SessionStart hooks invoked twice per session causing race conditions #14937 reports the same symptom but from a different angle (race conditions from double invocation)
• [BUG] Plugin cache keeps old versions and runs their hooks! #15621 is about old cached versions running hooks — related but different root cause

My issue specifically identifies the dual-path loading problem: Claude Code loads hooks from both ~/.claude/plugins/marketplaces/<name>/ AND ~/.claude/plugins/cache/<name>/ simultaneously for the same enabled plugin. This causes every hook to execute twice.

Evidence from today (2026-02-08):

• After renaming marketplaces/.../hooks.json → .bak, the UserPromptSubmit hook still fires twice
• Only ONE source exists in cache (thedotmack/claude-mem/9.0.17/hooks/hooks.json)
• No other enabled plugin has UserPromptSubmit hooks
• This confirms the bug is in the hook dispatcher itself, not just dual-path loading

This bug has been reported by multiple users since November 2025 (#10871, #14937, #15621) and remains unfixed. Please do not auto-close — it affects all plugins using the hooks system.

[backnotprop]

I'm seeing multiple hook calls on VS Code, firing twice.