github/copilot-sdk · error

failed to unmarshal delete response

Error message

failed to unmarshal delete response: %w

What it means

DeleteSession returns this error when the 'session.delete' result cannot be unmarshalled into deleteSessionResponse. The backend acknowledged the call but its response body was not the expected {success, error} object.

Solutions

1. Capture the raw result bytes and validate the expected {success, error} shape
2. Update client library and backend to the same version
3. Retry the delete; if it recurs, inspect backend logs for the failing session delete
4. Check whether a proxy/IPC layer is corrupting the response

Example fix

// before
err := client.DeleteSession(ctx, sessionID)
// after
err := client.DeleteSession(ctx, sessionID)
if err != nil && strings.Contains(err.Error(), "unmarshal delete response") {
    // fall back: verify via ListSessions whether the session is gone
}

if sessionID == "" {
    return fmt.Errorf("DeleteSession: empty sessionID")
}

func isDeleteUnmarshalError(err error) bool {
    return strings.Contains(err.Error(), "unmarshal delete response")
}

if err := client.DeleteSession(ctx, id); err != nil {
    if isDeleteUnmarshalError(err) {
        // verify deletion via ListSessions before retrying
        return fmt.Errorf("delete ack undecodable: %w", err)
    }
    return err
}

When it happens

Trigger: Calling DeleteSession when the backend returns a malformed or unexpected delete confirmation payload.

Common situations: Version mismatch between client and backend; backend crashed mid-response leaving a truncated payload; middleware rewriting the response.

Understand the failure class

Background: "failed to unmarshal" / json.Unmarshal errors: why parsing a response into a Go struct fails and how to fix it — this error's family across 23 libraries.

Related errors

• failed to unmarshal response
• failed to unmarshal sessions response
• failed to unmarshal session metadata response
• failed to unmarshal getLastId response
• failed to unmarshal getForeground response

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/d79ba3b20c08a0e8. Report an issue: GitHub.

Appendix: source

Thrown at go/client.go:1618

//	if err := client.DeleteSession(context.Background(), "session-123"); err != nil {
//	    log.Fatal(err)
//	}
func (c *Client) DeleteSession(ctx context.Context, sessionID string) error {
	unlockSession := c.lockSessionOperation(sessionID)
	defer unlockSession()

	if err := c.ensureConnected(ctx); err != nil {
		return err
	}

	result, err := c.client.Request(ctx, "session.delete", deleteSessionRequest{SessionID: sessionID})
	if err != nil {
		return err
	}

	var response deleteSessionResponse
	if err := json.Unmarshal(result, &response); err != nil {
		return fmt.Errorf("failed to unmarshal delete response: %w", err)
	}

	if !response.Success {
		errorMsg := "unknown error"
		if response.Error != nil {
			errorMsg = *response.Error
		}
		return fmt.Errorf("failed to delete session %s: %s", sessionID, errorMsg)
	}

	// Remove from local sessions map if present
	c.sessionsMux.Lock()
	session := c.sessions[sessionID]
	delete(c.sessions, sessionID)
	c.sessionsMux.Unlock()
	if session != nil {
		session.releaseGitHubTokenProviderRegistration()
	}

View on GitHub (pinned to cd8cf15dc3)