[BUG] SessionStart hook doesn't receive CLAUDE_ENV_FILE when installed by a plugin

[gabelevi]

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The https://code.claude.com/docs/en/hooks#persisting-environment-variables explains that a CLAUDE_ENV_FILE should be available to SessionStart hooks. I can verify this works for project hooks or personal hooks, but this does not work for plugin hooks.

What Should Happen?

The plugin hook should be passed CLAUDE_ENV_FILE

Error Messages/Logs

Steps to Reproduce

Put a repro here: https://github.com/gabelevi/claude_session_start_env_bug (it's basically the test plugin from the docs)

It has two hooks:

1. A local hook which does echo $CLAUDE_ENV_FILE > /tmp/CLAUDE_ENV_FILE_project.txt
2. A plugin hook which does echo $CLAUDE_ENV_FILE > /tmp/CLAUDE_ENV_FILE_plugin.txt

If I install the marketplace & plugin and restart claude, I can see that both /tmp/CLAUDE_ENV_FILE_plugin.txt and /tmp/CLAUDE_ENV_FILE_project.txt were created at the same time. But /tmp/CLAUDE_ENV_FILE_plugin.txt is always empty while /tmp/CLAUDE_ENV_FILE_project.txt contains the absolute path of my session's env file (e.g. /Users/username/.claude/session-env/c76b6e6b-25ce-453c-81e0-de5bc413ca2f/hook-0.sh)

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

2.0.36

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[dkmaker]

Where is quality control? :-)

This is a really stupid bug - but agree its confirmed - all works with the env file but its NOT created when the hook is added as a plugin then the $CLAUDE_ENV_FILE is NOT populated

You can as a workarround take the session id from the json and construct the CLAUDE_ENV_FILE with $CLAUDE_HOME/session-env/CLAUDE_SESSION_ID/hook-0.sh and then do the exports into that file - then it will be called - that works and can confirm it - i had to do it like that - Claude just reads the hook-0.sh when it loads bash sessions after that file is created i also store CLAUDE_SESSION_ID so i can use it later

# Read and log the input JSON
INPUT_JSON=$(cat)

# Extract session_id from JSON and export CLAUDE_SESSION_ID
export CLAUDE_SESSION_ID=$(echo "$INPUT_JSON" | grep -o '"session_id":"[^"]*"' | cut -d'"' -f4)

# Create CLAUDE_ENV_FILE if not set
if [ -z "$CLAUDE_ENV_FILE" ] && [ -n "$CLAUDE_SESSION_ID" ] && [ -n "$CLAUDE_HOME" ]; then
    export CLAUDE_ENV_FILE="$CLAUDE_HOME/session-env/$CLAUDE_SESSION_ID/hook-0.sh"
    # Create the directory if it doesn't exist
    mkdir -p "$(dirname "$CLAUDE_ENV_FILE")"
    # Create the file if it doesn't exist
    touch "$CLAUDE_ENV_FILE"
    echo "✓ Created CLAUDE_ENV_FILE: $CLAUDE_ENV_FILE" >> "$LOG_FILE"
fi

Im not sure what it breaks but i have no files in my whole session library other than hook-0.sh and ONLY files i created my self i presume each hook will have a unique file numbered so probably it should have a increment if it exists or just use a higher number but dont know how claude reads it :/

[dltn]

  Tested with reporter's exact repro from https://github.com/gabelevi/claude_session_start_env_bug:

  | Hook Type    | Before Fix                                        | After Fix                                         |
  |--------------|---------------------------------------------------|---------------------------------------------------|
  | Project hook | ✅ /Users/dalton/.claude/session-env/.../hook-0.sh | ✅ /Users/dalton/.claude/session-env/.../hook-0.sh |
  | Plugin hook  | ❌ (empty)                                         | ✅ /Users/dalton/.claude/session-env/.../hook-1.sh |

Thanks for the report & repro @gabelevi 😄 Fixed in next release.