Error responses missing `param` and `code` fields — OpenAI SDK error handling broken

[hankbobtheresearchoor]

Problem

The errorResponse() function only populates type and message in error responses. The OpenAI API spec requires code and optionally param fields in error objects. Their absence breaks SDK error handling that relies on programmatic error codes.

Current

func errorResponse(errType, message string) map[string]any {
    return map[string]any{
        "error": map[string]any{
            "type":    errType,
            "message": message,
        },
    }
}

OpenAI Spec

{
  "error": {
    "message": "Model 'gpt-5' not found",
    "type": "invalid_request_error",
    "param": "model",
    "code": "model_not_found"
  }
}

What Breaks

• Python SDK: except openai.NotFoundError as e: checks e.code — gets None
• Node SDK: error.code === 'model_not_found' — gets undefined
• Retry logic: SDKs use code to decide whether to retry (e.g., insufficient_quota vs rate_limit_exceeded)
• Error monitoring: Sentry/Datadog group by error.code, not error.message — all errors appear as one group

Proposed Fix

Expand errorResponse to accept optional param and code:

type errOpt struct {
    param string
    code  string
}

func errorResponse(errType, message string, opts ...errOpt) map[string]any {
    detail := map[string]any{
        "type":    errType,
        "message": message,
    }
    if len(opts) > 0 {
        if opts[0].param != "" {
            detail["param"] = opts[0].param
        }
        if opts[0].code != "" {
            detail["code"] = opts[0].code
        }
    } else {
        // Infer code from type when not explicitly provided
        detail["code"] = errType
    }
    return map[string]any{"error": detail}
}

Then update call sites that should include param:

• errorResponse("invalid_request_error", "model is required") → add param: "model"
• errorResponse("model_not_found", ...) → add code: "model_not_found"
• errorResponse("insufficient_funds", ...) → add code: "insufficient_funds"

Severity

🟠 HIGH — SDK error handling is fundamentally broken without code. Clients cannot programmatically distinguish error types.

Related

• Request/response pipeline uses map[string]any throughout — no field validation, no type safety, no SDK contract #141 (typed structs — this is the minimal fix for the error field gap)
• OpenAI API compatibility audit (2026-05-08)
• consumer.go:2549-2557