Unhandled Audits PerformanceIssue spams stderr: 'No handler registered for issue code PerformanceIssue'

[willtmc]

Summary

chrome-devtools-mcp@0.21.0 logs this warning repeatedly to stderr when Chrome emits an Audits issue with code PerformanceIssue:

No handler registered for issue code PerformanceIssue

In long-running agent sessions this can flood the terminal.

What I found

In the bundled DevTools frontend code, PerformanceIssue is present in the registered Audits.InspectorIssueCode enum, but there is no corresponding entry in issueCodeHandlers.

Evidence from the installed 0.21.0 bundle

The generated bundle includes:

inspectorBackend.registerEnum("Audits.InspectorIssueCode", {
  ...,
  PerformanceIssue: "PerformanceIssue",
  ...
});

But issueCodeHandlers does not include a PerformanceIssue handler, and the fallback path is:

function createIssuesFromProtocolIssue(issuesModel, inspectorIssue) {
    const handler = issueCodeHandlers.get(inspectorIssue.code);
    if (handler) {
        return handler(issuesModel, inspectorIssue);
    }
    console.warn(`No handler registered for issue code ${inspectorIssue.code}`);
    return [];
}

Repro shape

1. Start chrome-devtools-mcp@0.21.0
2. Attach it to a live Chrome session
3. Open / interact with a page that causes Chrome DevTools to emit Audits.issueAdded with code PerformanceIssue
4. Observe repeated stderr warnings:

No handler registered for issue code PerformanceIssue

Expected

One of:

• add a proper PerformanceIssue handler, or
• intentionally ignore / downgrade PerformanceIssue without warning spam, if this issue type is not meant to be surfaced yet.

Actual

The server warns on every occurrence, which is noisy enough to overwhelm terminal-based agent workflows.

Environment

• chrome-devtools-mcp: 0.21.0
• Chrome: current stable on macOS
• Invocation path: via npm exec chrome-devtools-mcp@latest ...

Local workaround

I locally patched the generated bundle to suppress the warning only for PerformanceIssue, and that eliminated the spam without affecting other unknown issue-code warnings.