[BUG] Teammates spawned in Delegate Mode lose tool access despite mode: bypassPermissions

Description

When the lead agent is in Delegate Mode (via Shift+Tab or /config → Default permission mode → Delegate), teammates spawned via the Task tool lose access to core tools (Bash, Read, Write, Edit) even when explicitly passed mode: "bypassPermissions" in the Task call.

The teammate launches, receives its prompt, but cannot execute any file operations. It effectively becomes a read-only agent that can only respond with text.

Reproduction Steps

1. Start Claude Code (v2.1.37)
2. Create an Agent Team via TeamCreate
3. Enter Delegate Mode (Shift+Tab)
4. Spawn a teammate:

``
Task tool call:
subagent_type: "general-purpose"
team_name: "{team-name}"
name: "worker-1"
mode: "bypassPermissions"
prompt: "Read src/index.ts and add a comment at the top"
``

1. Observe: teammate cannot call Read, Write, Edit, or Bash

Expected Behavior

mode: "bypassPermissions" on the Task call should grant the teammate full tool access regardless of the lead's current permission state. The lead's Delegate Mode restriction should apply only to the lead itself, not propagate to spawned children.

Actual Behavior

The teammate inherits the lead's Delegate Mode tool restrictions. The mode parameter on the Task call is overridden (or ignored) by the lead's session-level permission state. Tools like Bash, Read, Write, and Edit are unavailable to the teammate.

Workaround

Spawn all teammates before entering Delegate Mode. Once teammates are spawned, then switch to Delegate Mode. Teammates spawned before the mode switch retain their full tool access.

TeamCreate → Spawn teammates (full tools) → Enter Delegate Mode → Coordinate only

This workaround fails if you need to spawn additional teammates mid-run (e.g., adaptive respawn of a failed agent, adding an integrator role).

Environment

• Claude Code version: 2.1.37
• Platform: Linux (WSL2, Ubuntu)
• OS: Linux 6.6.87.2-microsoft-standard-WSL2

Related Issues

• #14297 — Delegate Mode is undocumented
• #15194 — Duplicate: no docs for Delegate Mode behavior
• #5465 — Task subagents fail to inherit permissions in MCP server mode
• #18950 — Skills/subagents don't inherit user-level permissions from settings.json
• #7296 — Agents don't inherit MCP tool access
• #4750 — Ambiguity in subagent behavior when main agent is in Plan Mode

Root Cause Hypothesis

The permission model appears to compute effective_permissions = min(mode_param, lead_session_state) rather than effective_permissions = mode_param. The lead's Delegate Mode acts as a ceiling on what permissions can be granted to children, rather than being a local restriction on the lead only.

This is the same class of bug as #5465, #18950, and #4750 — permission context doesn't flow cleanly from parent to child agent. Delegate Mode exacerbates it because it intentionally restricts the lead's tools, and that restriction leaks downward.