Summary

MS Teams delegated OAuth setup currently launches the browser with xdg-open on win32, so the native Windows path does not use the repository's normal Windows browser-open behavior.

Steps to reproduce

1. Stub process.platform to "win32".
2. Call openDelegatedOAuthUrl("https://example.com/oauth") from extensions/msteams/src/setup-surface.ts.
3. Observe the spawned command.

Expected behavior

On Windows, delegated OAuth setup should use the same browser-open command family as the shared helper in src/infra/browser-open.ts, which resolves to explorer.exe on win32.

Actual behavior

openDelegatedOAuthUrl() currently selects:

• open on macOS
• xdg-open on every other platform

That means win32 still tries xdg-open.

OpenClaw version

Observed on main at fbccc18e745e (2026-04-16) before the local fix.

Operating system

Windows 11 (repro validated with a local win32-targeted unit test in a source checkout).

Install method

Source checkout / local test workspace.

Model

N/A (setup-surface issue before model selection).

Provider / routing chain

N/A (delegated OAuth launcher path only).

Logs, screenshots, and evidence

Relevant code paths:

• extensions/msteams/src/setup-surface.ts:32-35
• src/infra/browser-open.ts:36-39

Local repro evidence:

• A targeted local repro test passed while asserting that openDelegatedOAuthUrl() calls xdg-open when process.platform === "win32".
• The same repro confirmed the shared browser-open helper still resolves to explorer.exe on win32.

Impact and severity

• Affected users/systems/channels: native Windows users configuring MS Teams delegated OAuth
• Severity: medium (can block or break browser launch during setup)
• Frequency: deterministic in the validated win32 repro path
• Consequence: delegated OAuth setup uses the wrong launcher on Windows and diverges from the repo's shared browser-open behavior

Additional information

This looks like a narrow cross-platform regression rather than a broader auth or token-handling issue. The smallest fix appears to be adding an explicit win32 -> explorer.exe branch (or reusing a platform-safe shared launcher through an allowed seam).