Workaround: Claude Code Agent Teams broken on AWS Bedrock (#25193)

bedrock-team-workaround.md

Workaround: Claude Code Agent Teams Broken on AWS Bedrock

Issue: anthropics/claude-code#25193

Problem

When using Claude Code with AWS Bedrock (CLAUDE_CODE_USE_BEDROCK=1), spawning team agent teammates fails because the Bedrock model identifier (e.g., us.anthropic.claude-opus-4-6-v1) gets normalized to the Anthropic API format (claude-opus-4-6), which Bedrock does not recognize.

This causes all teammate processes to fail with:

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

Root Cause

Claude Code's internal model ID normalization strips the Bedrock prefix (us.anthropic.) and suffix (-v1) when passing the model to teammate subprocesses.

Workaround

We exploit an internal env var CLAUDE_CODE_TEAMMATE_COMMAND that overrides which executable is used when spawning teammates. By pointing it at a wrapper script that rewrites --model args, we intercept and fix the model ID before it reaches the teammate process.

Step 1: Create the wrapper script

cat > ~/.local/bin/claude-bedrock-wrapper << 'SCRIPT'
#!/bin/bash
# Wrapper that rewrites --model args to use the Bedrock model ID.
# Spawned teammates get a normalized model ID (e.g., claude-opus-4-6)
# which Bedrock doesn't recognize. This rewrites it to the full Bedrock ID.
#
# See: https://github.com/anthropics/claude-code/issues/25193

BEDROCK_MODEL="${CLAUDE_BEDROCK_MODEL_OVERRIDE:-us.anthropic.claude-opus-4-6-v1}"
REAL_BINARY="$(readlink -f "$HOME/.local/bin/claude")"

args=()
while [[ $# -gt 0 ]]; do
  if [[ "$1" == "--model" ]]; then
    args+=("--model" "$BEDROCK_MODEL")
    shift 2  # skip the original model value
  else
    args+=("$1")
    shift
  fi
done

exec "$REAL_BINARY" "${args[@]}"
SCRIPT

chmod +x ~/.local/bin/claude-bedrock-wrapper

Step 2: Set the env var

Add to your ~/.zshrc (or ~/.bashrc):

export CLAUDE_CODE_TEAMMATE_COMMAND="$HOME/.local/bin/claude-bedrock-wrapper"

Step 3: Reload your shell

source ~/.zshrc

How It Works

1. Claude Code checks CLAUDE_CODE_TEAMMATE_COMMAND before using process.execPath when spawning teammates
2. The wrapper intercepts --model claude-opus-4-6 (or any normalized model) and replaces it with the full Bedrock model ID
3. Since env vars propagate to child processes, the wrapper is used at every level of spawning — even if a teammate spawns sub-teammates

Customization

To use a different Bedrock model, either:

• Edit the BEDROCK_MODEL default in the wrapper script, or
• Set CLAUDE_BEDROCK_MODEL_OVERRIDE in your shell:

  export CLAUDE_BEDROCK_MODEL_OVERRIDE="us.anthropic.claude-sonnet-4-5-20250929-v1:0"

Notes

• The wrapper resolves the real binary dynamically via the claude symlink, so it survives Claude Code auto-updates
• This only affects teammate/agent spawning — your main Claude Code session is unaffected
• Remove the env var to disable the workaround once the upstream fix ships