[BUG] Claude in Chrome side panel dictation always "Microphone access is blocked" — claude.ai iframe missing `microphone` in allow attribute (v1.0.85)

Summary

In the Claude in Chrome extension (v1.0.85), the dictation (microphone) button in the side panel always shows "Microphone access is blocked — To use dictation, select the site settings icon in your browser's address bar and allow the microphone", even when every relevant permission is granted. The side panel has no address bar, so the suggested remedy is impossible to follow.

Environment

• Claude in Chrome extension v1.0.85 (Chrome Web Store, id fcoeoabgfenejglbffodgkkbkcdhcgfn)
• Google Chrome (stable), macOS (Darwin 25.4.0, Mac mini)
• Working microphones present (USB mic + AirPods); mic capture verified working at OS level

Permissions state (all granted, verified)

• macOS TCC: com.google.Chrome → microphone allowed
• Chrome site settings: chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/ → microphone Allow
• Chrome site settings: https://claude.ai → microphone Allow
• Extension options page (options.html#permissions) shows "Microphone access granted" ✅

Despite all of the above, the side panel dictation button shows the "Microphone access is blocked" toast.

Root cause

The side panel hosts the chat UI in a cross-origin iframe pointing at claude.ai/cic/new?surface=cic_sidepanel. In assets/sidepanel-BSS8ARkQ.js the iframe is created with:

allow: "clipboard-read; clipboard-write"

The allow attribute does not include microphone. Under Permissions Policy, a cross-origin iframe cannot access the microphone unless the embedding document explicitly delegates it, so getUserMedia/mic permission inside the claude.ai iframe is denied unconditionally — no user-side setting can fix this.

(The "Microphone access granted" state on the options page belongs to a different feature — voice narration for workflow recording, on the extension's own origin — not to the embedded claude.ai composer.)

Repro

1. Install Claude in Chrome v1.0.85, sign in.
2. Grant mic permission everywhere (OS → Chrome, Chrome → extension origin, Chrome → claude.ai; options page shows granted).
3. Open the side panel, click the microphone button in the composer.
4. Toast: "Microphone access is blocked…".

Verification of the diagnosis

Loading a locally patched copy of the extension where the iframe allow attribute is changed to "clipboard-read; clipboard-write; microphone" makes the "blocked" toast go away (dictation still did not fully work in our test, so there may be an additional issue on top — e.g. prompt delegation inside the side panel context — but the missing allow entry is a hard blocker regardless).

Expected

Dictation works in the side panel, or at minimum the error message does not point to a nonexistent address bar.

Suggested fix

Add microphone to the iframe allow attribute in the side panel, and verify permission prompting/delegation works in the side panel context (cf. the well-known sidebar-iframe mic issue class, e.g. zen-browser/desktop#13026).