fix: record OAuth-host verification + models.json SPOT for usage-probe/default (#112) (#119)

Three alignment/SPOT findings from the 2026-05-31 audit:

1. The OAuth token-refresh host (platform.claude.com/v1/oauth/token, a Class A
   surface) was introduced in the 2026-04-11 drift commit and had no verification
   record. Verified against the compiled cli.js (claude.exe v2.1.154) via `strings`:
   OAUTH_TOKEN_URL and OAUTH_CLIENT_ID both appear in the binary byte-for-byte (in
   the same `prod` config object), and the legacy host console.anthropic.com/v1/oauth
   is absent (0 hits). Recorded this as an inline ALIGNMENT citation comment above the
   constants. No live OAuth probe was run — a refresh-token grant would rotate the
   operator's real credentials; the strings-on-binary evidence is decisive.
   (cli.js: verified against compiled claude.exe v2.1.154, 2026-05-31.)

2. fetchUsageFromApi() hardcoded the haiku model ID; now derives from
   modelsConfig.aliases.haiku (ADR 0003 SPOT). Prevents a silent /usage break on a
   future haiku ID bump.

3. [P3] The default request model hardcoded the sonnet ID; now derives from
   modelsConfig.aliases.sonnet (ADR 0003 SPOT).

Both SPOT values are byte-identical to the literals they replace today, so zero
behavior change — only drift-resistance. The alignment.yml blacklist pin for the
wrong-host variant was deliberately NOT included here: extending the blacklist is a
governance-layer change (alignment.yml inline policy) and belongs in its own PR.

ALIGNMENT.md: finding 1 IS the verification (cli.js citation recorded inline);
findings 2-3 are SPOT hygiene that forward no new operation. No blacklisted tokens or
port literals introduced; alignment.yml passes.

Independent fresh-context reviewer (opus) INDEPENDENTLY re-ran `strings` on the binary
and confirmed the host/client_id present and the legacy host absent — APPROVE (Iron
Rule 10; alignment hard-requirement #3 satisfied).

Closes #112.

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Fix
+
+- **#112** — Recorded OAuth-host verification against compiled cli.js v2.1.154 (ALIGNMENT Class A); usage-probe and default request model now derive from `models.json` (ADR 0003 SPOT) instead of hardcoded IDs.
+
 ### Security
 
 - **#109 P0** — `/health` no longer advertises `PROXY_ANONYMOUS_KEY` to remote callers by default. The `anonymousKey` field is now gated behind a new `PROXY_ADVERTISE_ANON_KEY=1` opt-in env var; localhost callers are always exempt. This prevents any LAN-reachable device from harvesting a working bearer credential from the unauthenticated `/health` endpoint.

server.mjs

@@ -1222,6 +1222,12 @@ function streamStringAsSSE(res, id, model, content) {
 
 let usageCache = { data: null, fetchedAt: 0 };
 const USAGE_CACHE_TTL = 5 * 60 * 1000; // 5 min
+// ALIGNMENT (Class A — OAuth bearer machinery). Verified against the compiled cli.js
+// (claude.exe v2.1.154) on 2026-05-31 via `strings`: both OAUTH_CLIENT_ID and
+// OAUTH_TOKEN_URL appear in the binary byte-for-byte; the legacy host
+// console.anthropic.com/v1/oauth is absent (0 hits). Re-verify on cli.js major bumps
+// using the compiled-binary protocol (strings on the Mach-O/ELF; no live OAuth probe —
+// a refresh-token grant would rotate the operator's real credentials). (issue #112)
 const OAUTH_CLIENT_ID = "9d1c250a-e61b-44d9-88ed-5944d1962f5e";
 const OAUTH_TOKEN_URL = "https://platform.claude.com/v1/oauth/token";
 
@@ -1329,7 +1335,7 @@ async function fetchUsageFromApi() {
   // Minimal /v1/messages request — we only need the response headers.
   // Mirrors Claude Code cli.js vE4: headers anthropic-ratelimit-unified-{5h,7d}-{utilization,reset}.
   const body = JSON.stringify({
-    model: "claude-haiku-4-5-20251001",
+    model: modelsConfig.aliases.haiku,
     max_tokens: 1,
     messages: [{ role: "user", content: "." }],
   });
@@ -1670,7 +1676,7 @@ async function handleChatCompletions(req, res) {
   try { parsed = JSON.parse(body); } catch { return jsonResponse(res, 400, { error: "Invalid JSON" }); }
 
   const messages = parsed.messages || parsed.input || [{ role: "user", content: parsed.prompt || "" }];
-  const model = parsed.model || "claude-sonnet-4-6";
+  const model = parsed.model || modelsConfig.aliases.sonnet;
   const stream = parsed.stream;
 
   // Validate model against known models

test-features.mjs

@@ -1654,6 +1654,27 @@ test("sanitizeError: multiple paths all stripped", () => {
   assert.ok(result.includes("[path]"), `expected [path] in: ${result}`);
 });
 
+// ── models.json SPOT wiring (issue #112) ────────────────────────────────────
+// Asserts that the alias values used by server.mjs (usage probe + default model)
+// match the expected IDs. A future alias rename that silently breaks these
+// code paths is caught here.
+import { readFileSync as spotReadFileSync } from "node:fs";
+import { fileURLToPath as spotFileURLToPath } from "node:url";
+import { dirname as spotDirname, join as spotJoin } from "node:path";
+
+console.log("\nmodels.json SPOT aliases (issue #112):");
+
+const _spotDir = spotDirname(spotFileURLToPath(import.meta.url));
+const _spotModels = JSON.parse(spotReadFileSync(spotJoin(_spotDir, "models.json"), "utf8"));
+
+test("models.json aliases.haiku === 'claude-haiku-4-5-20251001' (usage-probe SPOT)", () => {
+  assert.equal(_spotModels.aliases.haiku, "claude-haiku-4-5-20251001");
+});
+
+test("models.json aliases.sonnet === 'claude-sonnet-4-6' (default-request-model SPOT)", () => {
+  assert.equal(_spotModels.aliases.sonnet, "claude-sonnet-4-6");
+});
+
 // ── Cleanup ──
 closeDb();