streamed function arguments do not match the terminal respon

Error message

streamed function arguments do not match the terminal response

What it means

The terminal item.Arguments must equal the arguments accumulated from deltas or extend them (strings.HasPrefix check) — streamed deltas are treated as a prefix of the final JSON. If the terminal arguments diverge (neither equal nor an extension), the arguments the consumer already rendered are stale and possibly invalid JSON, so the adapter errors.

Source

Thrown at kernel/util/openai_completion.go:528

		return err
	}
	stream.responseOutput = output

	for index, raw := range response.Output {
		item, ok := responseOutputItem(raw)
		if !ok || item.Type != "function_call" {
			continue
		}
		current := stream.responseToolCalls[index]
		if current.ID != "" && item.CallID != "" && current.ID != item.CallID {
			return errors.New("streamed function call ID does not match the terminal response")
		}
		if current.Function.Name != "" && item.Name != "" && current.Function.Name != item.Name {
			return errors.New("streamed function name does not match the terminal response")
		}
		if current.Function.Arguments != item.Arguments &&
			!strings.HasPrefix(item.Arguments, current.Function.Arguments) {
			return errors.New("streamed function arguments do not match the terminal response")
		}
		delta := openai.ToolCall{Type: openai.ToolTypeFunction}
		deltaIndex := index
		delta.Index = &deltaIndex
		changed := false
		if current.ID == "" && item.CallID != "" {
			delta.ID = item.CallID
			changed = true
		}
		if current.Function.Name == "" && item.Name != "" {
			delta.Function.Name = item.Name
			changed = true
		}
		if current.Function.Arguments != item.Arguments && strings.HasPrefix(item.Arguments, current.Function.Arguments) {
			delta.Function.Arguments = strings.TrimPrefix(item.Arguments, current.Function.Arguments)
			changed = delta.Function.Arguments != "" || changed
		}
		if changed {

View on GitHub (pinned to afa823b6b4)

Solutions

Retry the request once — divergences are often transient.
Reproduce against the official OpenAI endpoint; if clean there, upgrade or replace the gateway.
Disable streaming for tool calls on the affected provider.
Report with a captured SSE trace of the streamed versus terminal arguments.

Defensive patterns

Strategy: retry

Try / catch

Discard the streamed argument accumulation and re-issue the request; never JSON-parse the partial arguments; switch to non-streaming for that provider if it persists.

Prevention

Use providers that stream argument deltas verbatim
Avoid gateways that normalize JSON during assembly
Capture SSE traces when certifying tool-calling providers

When it happens

Trigger: Providers that rewrite, reformat, or re-serialize argument JSON between streaming and the terminal response; content filters mutating arguments; gateways recomputing output items instead of echoing the streamed ones.

Common situations: Gateways that normalize JSON formatting (key ordering, whitespace) during assembly; moderation layers editing arguments post-hoc.

Related errors

AI-assisted analysis of siyuan-note/siyuan@afa823b6b4 (2026-08-18). Data as JSON: /api/errors/29c782c593d06211. Report an issue: GitHub.