The desktop sidecar can bind on LAN addresses for phone access, so the H5 settings switch must be an authorization boundary for remote capability routes, not only a token-mode toggle. Remote browser API, proxy, websocket, and SDK routes now fail closed while H5 is disabled; local desktop, Tauri, WebUI, adapter, and internal SDK paths remain tokenless. When H5 is enabled, remote API, proxy, and websocket requests must use the H5 token carried by the QR link, and the server API key cannot substitute for that H5 token.
Constraint: Desktop sidecar binds 0.0.0.0 while reporting loopback to local UI.
Constraint: Client-controlled Host and Origin headers cannot prove a local request; the boundary uses Bun requestIP instead.
Constraint: Static H5 shell and /health must still load so browser bootstrap can show a recovery flow.
Rejected: Trust loopback Host headers | LAN clients can spoof Host and Origin.
Rejected: Use ANTHROPIC_API_KEY as a remote H5 credential | it is not the phone pairing token and would weaken the QR-token boundary.
Confidence: high
Scope-risk: moderate
Directive: Do not make h5Enabled=false an open remote state for /api, /proxy, /ws, or /sdk routes.
Tested: bun test src/server/__tests__/h5-access-policy.test.ts src/server/__tests__/h5-access-auth.test.ts src/server/middleware/cors.test.ts
Tested: bun run check:server
The classifier should not treat every /sdk path as trusted by pathname, because LAN-exposed servers already have a narrower local SDK trust boundary.
Constraint: Desktop local chat, Tauri WebView, loopback adapters, and local SDK routes must remain tokenless.
Rejected: Path-only /sdk trust | a non-local caller could reach the SDK route through a LAN-bound server.
Confidence: high
Scope-risk: narrow
Directive: Keep remote /sdk and hostile-origin loopback requests in the H5/browser bucket unless a dedicated SDK auth layer is verified.
Tested: bun test src/server/__tests__/h5-access-policy.test.ts
Add a small standalone request classifier and focused server tests so later H5 token enforcement can target LAN/browser requests without changing the current desktop, SDK, or adapter paths.
Constraint: Task scope is limited to a standalone classifier plus tests in two server files
Constraint: Local desktop WebView, loopback integrations, and /sdk routes must remain tokenless for now
Rejected: Integrate the classifier into auth middleware now | this task only introduces the reusable classification seam
Confidence: high
Scope-risk: narrow
Directive: Keep local-trusted and internal-sdk classifications tokenless unless the server auth integration changes with matching regression coverage
Tested: bun test src/server/__tests__/h5-access-policy.test.ts
Tested: per-file TypeScript diagnostics for src/server/h5AccessPolicy.ts and src/server/__tests__/h5-access-policy.test.ts
Not-tested: Full server auth middleware integration
Not-tested: bun run check:server remains red from pre-existing repo dependency and unrelated test failures
