tmux teammate mode hardcodes model ID, breaking Bedrock/custom provider setups

Description

When launching Claude Code with claude --teammate-mode tmux and then spawning a team of agents, the subprocess command hardcodes the model ID (e.g. --model claude-opus-4-6):

cd $HOME && env CLAUDECODE=1 CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 /path/to/claude \
  --agent-id <agent-id>@<team> \
  --agent-name <agent-name> \
  --team-name <team> \
  --agent-color green \
  --parent-session-id <session-id> \
  --agent-type Bash \
  --model claude-opus-4-6

Problem

The --model flag is set to a hardcoded canonical model name (e.g. claude-opus-4-6), but users who connect through AWS Bedrock (or other providers) use different model IDs (e.g. bedrock/us.anthropic.claude-opus-4-6-v1).

Because the spawned teammate process uses the hardcoded model ID instead of the provider-specific model ID from the parent session, the tmux teammate mode fails for non-default provider configurations.

Expected Behavior

The tmux teammate mode should propagate the actual model ID being used by the parent session (including provider prefix) to the spawned teammate agents, rather than hardcoding the canonical model name.

Steps to Reproduce

1. Configure Claude Code to use a Bedrock model (e.g. bedrock/us.anthropic.claude-opus-4-6-v1)
2. Launch with claude --teammate-mode tmux
3. Spawn a team of agents
4. Observe that the tmux panes launch with --model claude-opus-4-6 instead of the Bedrock model ID

Environment

• Claude Code version: 2.1.x
• Provider: AWS Bedrock
• OS: macOS