Team agent teammates receive normalized model ID instead of Bedrock model ID, causing 400 errors

Bug Description

When using Claude Code with AWS Bedrock (CLAUDE_CODE_USE_BEDROCK=1), spawning team agent teammates fails because the Bedrock model identifier is normalized to the Anthropic API format, which Bedrock does not recognize.

Environment

• Claude Code version: 2.1.39
• OS: macOS (Darwin 25.2.0)
• API Provider: AWS Bedrock (CLAUDE_CODE_USE_BEDROCK=1)
• Model: us.anthropic.claude-opus-4-6-v1
• Feature flag: CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1

Steps to Reproduce

1. Configure Claude Code to use Bedrock:

``json
// settings.json
{
"env": {
"CLAUDE_CODE_USE_BEDROCK": "1",
"AWS_REGION": "us-east-1"
},
"model": "us.anthropic.claude-opus-4-6-v1"
}
``

1. Create a team using TeamCreate
2. Spawn a teammate using the Task tool with team_name parameter

Expected Behavior

The teammate process should be spawned with the full Bedrock model ID:

claude --model us.anthropic.claude-opus-4-6-v1 --agent-id agent-b@team-name ...

Actual Behavior

The teammate process is spawned with a normalized (Anthropic API format) model ID:

claude --model claude-opus-4-6 --agent-id agent-b@team-name ...

This causes:

API Error (claude-opus-4-6): 400 The provided model identifier is invalid.

Evidence

Team config file shows the discrepancy clearly:

{
  "members": [
    {
      "name": "team-lead",
      "model": "us.anthropic.claude-opus-4-6-v1"   // ✅ Correct Bedrock format
    },
    {
      "name": "agent-b",
      "model": "claude-opus-4-6"                     // ❌ Normalized to Anthropic API format
    }
  ]
}

Actual spawned process (from ps aux):

/Users/.../.local/share/claude/versions/2.1.39 \
  --agent-id agent-b@bedrock-comm-test \
  --agent-name agent-b \
  --team-name bedrock-comm-test \
  --model claude-opus-4-6              # ← Should be us.anthropic.claude-opus-4-6-v1

Root Cause

Claude Code's internal model ID normalization logic strips the Bedrock prefix (us.anthropic.) and suffix (-v1) when passing the model identifier to teammate subprocesses. This normalization is appropriate for Anthropic API but breaks Bedrock compatibility.

Impact

• Team/swarm features are completely non-functional when using Bedrock as the API provider
• Both TeamCreate + Task (with team_name) and standalone Task tool teammate spawning are affected
• The main session works fine; only spawned teammates fail