[BUG] Task tool with subagent_type "Bash" auto-denies Bash commands when run_in_background: true

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?

When using the Task tool with subagent_type: "Bash" and run_in_background: true, all Bash commands are auto-denied without prompting the user. This is especially counterintuitive because the "Bash" agent type is described as a "Command execution specialist for running bash commands" — yet it cannot execute any bash commands when running in the background.

Actual Behavior

• All Bash commands are silently auto-denied
• The error message says "Permission to use Bash has been denied"
• No prompt is shown to the user
• The agent cannot accomplish anything and returns a failure message

Context

I was using 4 parallel background Bash agents to collect GitHub PR review comments via gh api. All 4 agents failed identically because they could not run any Bash commands.

// All 4 of these agents failed
Task({
  subagent_type: "Bash",
  run_in_background: true,
  prompt: "Run this python script that calls gh api..."
})

Environment

• Claude Code Version: 2.1.39
• Platform: Linux (WSL2)
• OS: Linux 5.15.146.1-microsoft-standard-WSL2

Workaround

Related issue #18172 suggests using PreToolUse hooks to override the auto-deny behavior, but this should not be necessary for an agent type whose only purpose is running Bash commands.

Related Issues

• #18172 - Background agents cannot run Bash commands (closed, not planned)
• #18885 - Allow subagents to forward permission requests
• #27249 - Background agents in skill context can't execute Bash

What Should Happen?

Expected Behavior

A "Bash" agent type should be able to execute bash commands — that is its entire purpose. At minimum, one of the following should apply:

• Background Bash agents inherit the permissions already granted in the parent session
• Background Bash agents prompt the user for permission (forwarding the prompt to the foreground)
• The subagent_type: "Bash" agent has implicit Bash tool permission, since that is its sole capability

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Call the Task tool with:

• subagent_type: "Bash"
• run_in_background: true
• A prompt that instructs the agent to run a bash command (e.g., gh api ... or python3 ...)

1. The agent attempts to use the Bash tool
2. The command is auto-denied with: "Permission to use Bash has been denied"

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.68

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_