fix(thinking): clamp below-range requests down to the cheapest level, not up

obuchowski · steipete · commit e2d9002cac6a · 2026-07-07T01:42:33.000-04:00
resolveSupportedThinkingLevelFromProfile sorts the supported levels descending, then, when every supported level exceeds the request (e.g. a stored `off` on a profile that has no off level), fell through to `ranked.find(non-off)` — the first entry of a descending list, i.e. the most expensive level. A session carrying thinking `off` that switched onto such a model was silently remapped to maximum reasoning and persisted (src/auto-reply/reply/directive-handling.persist.ts). Use `ranked.findLast(non-off)` so a below-range request resolves to the cheapest non-off level instead. Regression test included (red before, green after). This surfaces with the first bundled no-off thinking profiles (Fireworks GPT-OSS 120B, see #92217), but the clamp lives in shared core logic, so it ships on its own.
diff --git a/src/auto-reply/thinking.test.ts b/src/auto-reply/thinking.test.ts
@@ -648,6 +648,20 @@ describe("listThinkingLevels", () => {
       }),
     ).toBe("high");
   });
+
+  it("clamps a below-range request down to the cheapest level on a no-off profile", () => {
+    providerRuntimeMocks.resolveProviderThinkingProfile.mockReturnValue({
+      levels: [{ id: "low" }, { id: "medium" }, { id: "high" }],
+    });
+
+    expect(
+      resolveSupportedThinkingLevel({
+        provider: "demo-noff",
+        model: "demo-model",
+        level: "off",
+      }),
+    ).toBe("low");
+  });
 });
 
 describe("listThinkingLevelLabels", () => {
diff --git a/src/auto-reply/thinking.ts b/src/auto-reply/thinking.ts
@@ -350,7 +350,7 @@ function resolveSupportedThinkingLevelFromProfile(
   const ranked = profile.levels.toSorted((a, b) => b.rank - a.rank);
   return (
     ranked.find((entry) => entry.id !== "off" && entry.rank <= requestedRank)?.id ??
-    ranked.find((entry) => entry.id !== "off")?.id ??
+    ranked.findLast((entry) => entry.id !== "off")?.id ??
     "off"
   );
 }

Original file line number	Diff line number	Diff line change
`@@ -350,7 +350,7 @@ function resolveSupportedThinkingLevelFromProfile(`
`350`	`350`	`const ranked = profile.levels.toSorted((a, b) => b.rank - a.rank);`
`351`	`351`	`return (`
`352`	`352`	`ranked.find((entry) => entry.id !== "off" && entry.rank <= requestedRank)?.id ??`
`353`		`- ranked.find((entry) => entry.id !== "off")?.id ??`
	`353`	`+ ranked.findLast((entry) => entry.id !== "off")?.id ??`
`354`	`354`	`"off"`
`355`	`355`	`);`
`356`	`356`	`}`