What causes "Zen Messages request should succeed" in Hmbown/CodeWhale?

Print the error (`{e:?}`) to distinguish send failure from response-parse failure.

Zen Messages request should succeed

Error message

Zen Messages request should succeed

What it means

Test-side `.expect("Zen Messages request should succeed")` panic. `create_message` returned `Err` for a `WireFormat::AnthropicMessages` client hitting the mocked `/v1/messages` endpoint. The non-streaming Anthropic Messages path failed to complete, either before sending (route/auth resolution) or on a non-2xx/unparseable response.

Solutions

Print the error (`{e:?}`) to distinguish send failure from response-parse failure.
Verify the mock mounted at `POST /v1/messages` returns the full Anthropic Messages JSON fixture including `usage`.
Confirm `client.wire_format == WireFormat::AnthropicMessages` (asserted above) so the request targets `/v1/messages`.
If the client's auth changed, remember Messages uses `x-api-key` + `anthropic-version`, not Bearer.

Example fix

// before
client
    .create_message(minimal_zen_request("claude-sonnet-4-6"))
    .await
    .expect("Zen Messages request should succeed");
// after
client
    .create_message(minimal_zen_request("claude-sonnet-4-6"))
    .await
    .unwrap_or_else(|e| panic!("Zen Messages request should succeed: {e:?}"));

Defensive patterns

Strategy: try-catch

Validate before calling

// Rust (preconditions)
assert_eq!(client.wire_format, WireFormat::AnthropicMessages);
// fixture must satisfy the parser:
assert!(fixture.get("usage").is_some() && fixture.get("content").is_some());

Try / catch

match client.create_message(req).await {
    Ok(msg) => assert!(!msg.content.is_empty()),
    Err(e) => panic!("Messages request should succeed: {e:?}"),
}

Prevention

Keep the Anthropic Messages fixture complete: id, type, role, content, stop_reason, usage.
Update the response parser and fixtures in the same commit.
Assert wire_format before the call to catch route misresolution early.
Remember Messages auth is x-api-key + anthropic-version, not Bearer.

When it happens

Trigger: Running `opencode_zen_messages_request_shape_uses_api_key_anthropic_route` when the mock route path no longer matches (`/v1/messages`), the client resolves a different wire format for claude-sonnet-4-6, or the mocked JSON response no longer satisfies the Messages response parser (missing `content`, `stop_reason`, or `usage` fields).

Common situations: Changing the Anthropic response schema the parser expects; route constants or base_url changes; mock fixture edited so required fields (`id`, `type`, `role`, `content`, `usage`) are missing.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/0c50052a9f47816d. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/client.rs:8170

                "id": "msg_zen",
                "type": "message",
                "role": "assistant",
                "content": [{"type": "text", "text": "ok"}],
                "model": "claude-sonnet-4-6",
                "stop_reason": "end_turn",
                "stop_sequence": null,
                "usage": {"input_tokens": 1, "output_tokens": 1}
            })))
            .expect(1)
            .mount(&server)
            .await;

        let client = opencode_zen_client(&server, "claude-sonnet-4-6");
        assert_eq!(client.wire_format, WireFormat::AnthropicMessages);
        client
            .create_message(minimal_zen_request("claude-sonnet-4-6"))
            .await
            .expect("Zen Messages request should succeed");

        let requests = server.received_requests().await.expect("recorded request");
        assert_eq!(requests.len(), 1);
        assert_zen_messages_api_key_without_bearer(&requests[0]);
        assert_eq!(
            requests[0]
                .headers
                .get("anthropic-version")
                .and_then(|value| value.to_str().ok()),
            Some("2023-06-01")
        );
    }

    #[tokio::test]
    async fn opencode_zen_chat_request_uses_chat_completions_route() {
        let server = MockServer::start().await;
        Mock::given(method("POST"))
            .and(path("/v1/chat/completions"))

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