micro/go-micro · error

a2a tasks/resubscribe: %s (%d)

Error message

a2a tasks/resubscribe: %s (%d)

What it means

Inside the tasks/resubscribe SSE stream, each data frame is a JSON-RPC-style envelope that can carry an error object. The library surfaces out.Error (message and code) through this error when the server reports an application-level error on the stream, even though the HTTP status was 200. The stream is terminated after emitting it.

Source

Thrown at gateway/a2a/client.go:192

		for scanner.Scan() {
			line := scanner.Text()
			if !strings.HasPrefix(line, "data:") {
				continue
			}
			payload := strings.TrimSpace(strings.TrimPrefix(line, "data:"))
			if payload == "" {
				continue
			}
			var out struct {
				Result Task      `json:"result"`
				Error  *rpcError `json:"error"`
			}
			if err := json.Unmarshal([]byte(payload), &out); err != nil {
				errs <- err
				return
			}
			if out.Error != nil {
				errs <- fmt.Errorf("a2a tasks/resubscribe: %s (%d)", out.Error.Message, out.Error.Code)
				return
			}
			select {
			case <-ctx.Done():
				errs <- ctx.Err()
				return
			case tasks <- out.Result:
			}
			if terminal(out.Result.Status.State) {
				return
			}
		}
		if err := scanner.Err(); err != nil {
			errs <- err
		}
	}()
	return tasks, errs
}

View on GitHub (pinned to 24529f1404)

Solutions

1. Check the JSON-RPC code in the error: 'task not found' means start over with SendMessage; auth codes mean refresh credentials.
2. Validate the resubscribe request payload (task ID, context ID) against the current A2A spec version the agent implements.
3. Fall back to polling tasks/get for final state if the stream cannot be re-established.
4. Log the server message verbatim; it usually names the exact invalid field or task.

select {
case err := <-errs:
	if strings.HasPrefix(err.Error(), "a2a tasks/resubscribe:") {
		var rpcErr struct{ Message string; Code int }
		// extract message/code; route on code (-32602, task-not-found, auth)
	}
case ev := <-events:
}

When it happens

Trigger: The remote agent pushes a JSON-RPC error frame (e.g. code -32602 invalid params, -32001 task not found, auth error) as the first event of the resubscribe stream, typically because the task ID is unknown or the request payload was rejected.

Common situations: Resubscribing to a task the agent no longer tracks; sending a resubscribe request missing required fields after an API change; agent-side authorization revocation mid-session.

Related errors

• tasks/resubscribe: status %d
• failed to parse stream chunk: %w
• anthropic stream error: %s
• failed to parse stream chunk: %w
• failed to parse stream chunk: %w

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/1d60d56d5e5bc25a. Report an issue: GitHub.