microsoft/playwright · error · Error

Unknown connect filter: ${connectFilter}

Error message

Unknown connect filter: ${connectFilter}

What it means

Error "Unknown connect filter: ${connectFilter}" thrown in microsoft/playwright.

Source

Thrown at packages/playwright-core/src/remote/playwrightServer.ts:122

        try {
          launchOptions = JSON.parse(launchOptionsParam || launchOptionsHeaderValue);
          if (!launchOptions.timeout)
            launchOptions.timeout = DEFAULT_PLAYWRIGHT_LAUNCH_TIMEOUT;
        } catch (e) {
        }

        const isExtension = this._options.mode === 'extension';
        launchOptions = filterLaunchOptions(launchOptions, isExtension || !!this._options.unsafe);

        // Always override artifacts dir with the one from server options.
        if (this._options.artifactsDir)
          launchOptions.artifactsDir = this._options.artifactsDir;

        if (isExtension) {
          const connectFilter = url.searchParams.get('connect');
          if (connectFilter) {
            if (connectFilter !== 'first')
              throw new Error(`Unknown connect filter: ${connectFilter}`);
            return new PlaywrightConnection(
                browserSemaphore,
                new WebSocketServerTransport(ws),
                false,
                this._playwright,
                () => this._initConnectMode(id, connectFilter, browserName, launchOptions),
                id,
            );
          }

          if (url.searchParams.has('debug-controller')) {
            return new PlaywrightConnection(
                controllerSemaphore,
                new WebSocketServerTransport(ws),
                true,
                this._playwright,
                async () => { throw new Error('shouldnt be used'); },
                id,

View on GitHub (pinned to c8fc3bf8d3)

When it happens

Trigger: Thrown at packages/playwright-core/src/remote/playwrightServer.ts:122 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/playwright@c8fc3bf8d3 (2026-08-12). Data as JSON: /api/errors/fe2f5cf4ef891d6d. Report an issue: GitHub.