[BUG] Installing plugins on Claude Code for Web Envs not working as expected

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?

I’m trying to get Superpowers plugin working in my project when launching the web-based coding agents on claude.ai/code.

According to the docs, it should be possible to install dependencies via the web agent using the dependency management instructions here:
https://code.claude.com/docs/en/claude-code-on-the-web#dependency-management

However, when I include the CLI commands to install the Superpowers plugin, the agent becomes unresponsive:

claude plugin marketplace add obra/superpowers-marketplace
claude plugin install superpowers@superpowers-marketplace

Both the hook and CLI commands work perfectly fine locally. I’ve also verified that the SessionStart hook can echo debugging statements when using the web agents — but it seems to hang when installing plugins this way.

What Should Happen?

Claude Code on Web should be able to access plugin resources when coding

Error Messages/Logs

Steps to Reproduce

1. in your project create .claude/hooks/session-start

.sh with the following content

#!/bin/bash
set -e

IS_CLOUD="${CLAUDE_CODE_REMOTE:-false}"

echo "🚀 SessionStart hook executed successfully!"
echo "Environment: $([ "$IS_CLOUD" = "true" ] && echo "cloud" || echo "local")"
echo "Project: $CLAUDE_PROJECT_DIR"
echo "Timestamp: $(date)"

if [ "$CLAUDE_CODE_REMOTE" != "true" ]; then
  echo "Running in local environment - skipping plugin installs"
  exit 0
fi

echo "Running in cloud environment - installing plugins..."

claude plugin marketplace add obra/superpowers-marketplace
echo "Plugins marketplace added successfully"

claude plugin install superpowers@superpowers-marketplace --scope project
echo "Plugins installed successfully"

Make the script executable:
chmod +x .claude/hooks/session-start.sh

in settings.json add the following hook:

{
  "hooks": {
    "SessionStart": [
      {
        "matcher": "startup",
        "hooks": [
          {
            "type": "command",
            "command": "\"$CLAUDE_PROJECT_DIR\"/.claude/hooks/session-start.sh"
          }
        ]
      }
    ]
  }
}

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.4

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_