It did not work. Here is why.

Seven failures cover almost every first run. Each one starts with the message on your screen.

1. 01

   You see

   401 authentication_error

   Because

   The key sent by the client is not the key the proxy generated. Regenerating it in the dashboard invalidates the old one immediately.

   Fix

   Copy the sq- key from the dashboard Endpoint page and set it again in the client. It goes in x-api-key or Authorization: Bearer — either works, but only one of them at a time.

2. 02

   You see

   cannot resolve provider

   Because

   The model string does not match any routing rule. A bare name with no prefix and no slash cannot be routed to anyone.

   Fix

   Use provider/model to be explicit — claude/claude-sonnet-5. The full table of prefixes and aliases is in the routing section of the docs.

3. 03

   You see

   502, or a provider error passed straight through

   Because

   The upstream credential is expired, revoked, or out of quota. The proxy forwards what the provider said rather than inventing a message.

   Fix

   Open the connection in the dashboard and press Test. It shows the last error verbatim. An OAuth login that has lapsed needs signing in again; an API key that was rotated needs pasting again.

4. 04

   You see

   address already in use

   Because

   Something else holds port 20130 — most often a second copy of the binary still running.

   Fix

   Start it on another port with -port, or stop the process holding it. On Windows: netstat -ano | findstr 20130, then Stop-Process on the PID it names.

5. 05

   You see

   Claude Code or Codex still talks to the provider directly

   Because

   The CLI read its config before you switched it over. Neither tool re-reads that file while running.

   Fix

   Quit the CLI completely and start it again. If it still bypasses the proxy, check that the dashboard reports the integration as enabled — it writes the config only once.

6. 06

   You see

   x509 or certificate errors on a corporate network

   Because

   A TLS-inspecting proxy is re-signing traffic with a certificate the Go binary does not trust.

   Fix

   Add your organisation’s root certificate to the system trust store. The binary uses the OS store; it does not carry its own bundle.

7. 07

   You see

   A Claude model works in Claude Code but not in your own SDK

   Because

   That model is served through a claude.ai subscription login, and the credential is only accepted by Anthropic’s own clients.

   Fix

   Connect an Anthropic API key for third-party SDKs. The models page marks every OAuth-only model, so you can tell before you wire anything up.