Claude Code¶

Claude Code speaks the Anthropic Messages API, which alcf-proxy serves at /v1/messages.

1. Start the proxy¶

alcf-proxy serve        # http://localhost:11445

2. Point Claude Code at the proxy¶

Claude Code reads the Anthropic base URL from environment variables. Set the base URL to the proxy's host root (Claude Code appends /v1/messages itself) and use a dummy key:

Linux / macOSWindows (PowerShell)Windows (cmd)

export ANTHROPIC_BASE_URL="http://localhost:11445"
export ANTHROPIC_API_KEY="dummy"
claude

$env:ANTHROPIC_BASE_URL = "http://localhost:11445"
$env:ANTHROPIC_API_KEY = "dummy"
claude

set ANTHROPIC_BASE_URL=http://localhost:11445
set ANTHROPIC_API_KEY=dummy
claude

To make it persistent, add those exports to your shell profile (~/.bashrc, ~/.zshrc) or set them as user environment variables on Windows.

Choosing the model¶

alcf-proxy forwards to its configured ALCF model (default openai/gpt-oss-120b). If you want a specific model and your Claude Code version lets you set one, use the id for the active cluster (alcf-proxy models lists them). Otherwise the proxy's default_model / active endpoint is used.

How translation works

Claude Code sends Anthropic Messages requests; alcf-proxy converts them to ALCF's streaming chat upstream and converts the streamed reply back into Anthropic SSE events (message_start → content_block_delta → message_stop). This is all automatic.

Don't disturb an existing argo / default setup¶

ANTHROPIC_BASE_URL only affects the shell/session where you set it. To switch back to your normal Claude Code backend, unset it:

Linux / macOSWindows (PowerShell)

unset ANTHROPIC_BASE_URL ANTHROPIC_API_KEY

Remove-Item Env:ANTHROPIC_BASE_URL, Env:ANTHROPIC_API_KEY

Troubleshooting¶

Empty replies / hangs — check alcf-proxy health; the upstream cluster may be down (failover should kick in). See Troubleshooting.
Auth errors — the dummy key is fine; real auth is the proxy's job. Run alcf-proxy auth status to confirm the proxy itself is authenticated.