fix: expand override.category and explicit reasoningEffort priority (#1219) (#1235)

* fix: expand override.category and explicit reasoningEffort priority (#1219)

Two bugs fixed:

1. createBuiltinAgents(): override.category was never expanded into concrete
   config properties (model, variant, reasoningEffort, etc.). Added
   applyCategoryOverride() helper and applied it in the standard agent loop,
   Sisyphus path, and Atlas path.

2. Prometheus config-handler: reasoningEffort/textVerbosity/thinking from
   direct override now use explicit priority chains (direct > category)
   matching the existing variant pattern, instead of relying on spread
   ordering.

Priority order (highest to lowest):
  1. Direct override properties
  2. Override category properties
  3. Resolved variant from model fallback chain
  4. Factory base defaults

Closes #1219

* fix: use undefined check for thinking to allow explicit false

src/agents/utils.test.ts

@@ -407,3 +407,119 @@ describe("buildAgent with category and skills", () => {
     expect(agent.prompt).not.toContain("agent-browser open")
   })
 })
+
+describe("override.category expansion in createBuiltinAgents", () => {
+  test("standard agent override with category expands category properties", async () => {
+    // #given
+    const overrides = {
+      oracle: { category: "ultrabrain" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
+
+    // #then - ultrabrain category: model=openai/gpt-5.2-codex, variant=xhigh
+    expect(agents.oracle).toBeDefined()
+    expect(agents.oracle.model).toBe("openai/gpt-5.2-codex")
+    expect(agents.oracle.variant).toBe("xhigh")
+  })
+
+  test("standard agent override with category AND direct variant - direct wins", async () => {
+    // #given - ultrabrain has variant=xhigh, but direct override says "max"
+    const overrides = {
+      oracle: { category: "ultrabrain", variant: "max" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
+
+    // #then - direct variant overrides category variant
+    expect(agents.oracle).toBeDefined()
+    expect(agents.oracle.variant).toBe("max")
+  })
+
+  test("standard agent override with category AND direct reasoningEffort - direct wins", async () => {
+    // #given - custom category has reasoningEffort=xhigh, direct override says "low"
+    const categories = {
+      "test-cat": {
+        model: "openai/gpt-5.2",
+        reasoningEffort: "xhigh" as const,
+      },
+    }
+    const overrides = {
+      oracle: { category: "test-cat", reasoningEffort: "low" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL, categories)
+
+    // #then - direct reasoningEffort wins over category
+    expect(agents.oracle).toBeDefined()
+    expect(agents.oracle.reasoningEffort).toBe("low")
+  })
+
+  test("standard agent override with category applies reasoningEffort from category when no direct override", async () => {
+    // #given - custom category has reasoningEffort, no direct reasoningEffort in override
+    const categories = {
+      "reasoning-cat": {
+        model: "openai/gpt-5.2",
+        reasoningEffort: "high" as const,
+      },
+    }
+    const overrides = {
+      oracle: { category: "reasoning-cat" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL, categories)
+
+    // #then - category reasoningEffort is applied
+    expect(agents.oracle).toBeDefined()
+    expect(agents.oracle.reasoningEffort).toBe("high")
+  })
+
+  test("sisyphus override with category expands category properties", async () => {
+    // #given
+    const overrides = {
+      sisyphus: { category: "ultrabrain" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
+
+    // #then - ultrabrain category: model=openai/gpt-5.2-codex, variant=xhigh
+    expect(agents.sisyphus).toBeDefined()
+    expect(agents.sisyphus.model).toBe("openai/gpt-5.2-codex")
+    expect(agents.sisyphus.variant).toBe("xhigh")
+  })
+
+  test("atlas override with category expands category properties", async () => {
+    // #given
+    const overrides = {
+      atlas: { category: "ultrabrain" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
+
+    // #then - ultrabrain category: model=openai/gpt-5.2-codex, variant=xhigh
+    expect(agents.atlas).toBeDefined()
+    expect(agents.atlas.model).toBe("openai/gpt-5.2-codex")
+    expect(agents.atlas.variant).toBe("xhigh")
+  })
+
+  test("override with non-existent category has no effect on config", async () => {
+    // #given
+    const overrides = {
+      oracle: { category: "non-existent-category" } as any,
+    }
+
+    // #when
+    const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
+
+    // #then - no category-specific variant/reasoningEffort applied from non-existent category
+    expect(agents.oracle).toBeDefined()
+    const agentsWithoutOverride = await createBuiltinAgents([], {}, undefined, TEST_DEFAULT_MODEL)
+    expect(agents.oracle.model).toBe(agentsWithoutOverride.oracle.model)
+  })
+})