What causes "no response from API" in micro/go-micro?

Inspect the raw response body for a filter/finish_reason indication (log the full body before this check).

no response from API

Error message

no response from API

What it means

After a successful JSON decode, callAPI checks that chatResp.Choices is non-empty; if the API returned a valid chat-completion envelope with zero choices, this plain error is thrown. It means the request technically succeeded but the model produced no selectable completion.

Source

Thrown at ai/atlascloud/atlascloud.go:470

		}
		return nil, nil, &atlascloudAPIError{Status: httpResp.Status, Code: httpResp.StatusCode, Retry: retryAfter, Phase: phase, Summary: atlascloudRequestSummary(req), Body: string(respBody)}
	}

	var chatResp struct {
		Choices []struct {
			Message struct {
				Content   string          `json:"content"`
				ToolCalls []atlasToolCall `json:"tool_calls"`
			} `json:"message"`
		} `json:"choices"`
	}

	if err := json.Unmarshal(respBody, &chatResp); err != nil {
		return nil, nil, fmt.Errorf("failed to parse response: %w", err)
	}

	if len(chatResp.Choices) == 0 {
		return nil, nil, fmt.Errorf("no response from API")
	}

	choice := chatResp.Choices[0]
	response := &ai.Response{
		Reply: choice.Message.Content,
	}

	for _, tc := range choice.Message.ToolCalls {
		var input map[string]any
		if err := json.Unmarshal([]byte(tc.Function.Arguments), &input); err != nil {
			input = map[string]any{}
		}
		response.ToolCalls = append(response.ToolCalls, ai.ToolCall{
			ID:    tc.ID,
			Name:  tc.Function.Name,
			Input: input,
		})
	}

View on GitHub (pinned to 24529f1404)

Solutions

Inspect the raw response body for a filter/finish_reason indication (log the full body before this check).
Verify the requested model name and that the messages/prompt payload is non-empty and well-formed.
Retry the request; if reproducible, rephrase the prompt to avoid content that may be filtered.
Treat it as retryable transient behavior and add backoff retry at the Generate call site.

Defensive patterns

Strategy: fallback

Try / catch

resp, err := provider.Generate(ctx, req)
if err != nil {
    if strings.Contains(err.Error(), "no response from API") {
        // retry once or fall back to another provider/model
        resp, err = provider.Generate(ctx, req)
    }
    if err != nil {
        return err
    }
}

Prevention

Always send a non-empty messages/prompt payload.
Use model names verified against the current AtlasCloud model list.
Inspect finish_reason / raw body when empty responses occur to detect moderation filtering.
Add a retry with backoff for empty responses, which are often transient.

When it happens

Trigger: json.Unmarshal succeeds but len(chatResp.Choices) == 0 — the API replied 200 with choices: [] (or omitted), e.g. the request was entirely filtered or the model returned nothing.

Common situations: Prompt fully consumed by moderation/safety filtering, an invalid model name that the API accepts but yields no output, empty prompt/messages payload, or provider-side degraded responses during outages.

Understand the failure class

Background: "empty response", "returned no data", "empty embeddings": what HTTP 200-with-empty-body errors mean across libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/0af0b5a8e975ec75. Report an issue: GitHub.