diff --git a/src/plugin-handlers/config-handler.test.ts b/src/plugin-handlers/config-handler.test.ts
new file mode 100644
index 0000000000..9724965fe3
--- /dev/null
+++ b/src/plugin-handlers/config-handler.test.ts
@@ -0,0 +1,104 @@
+import { describe, test, expect } from "bun:test"
+import { resolveCategoryConfig } from "./config-handler"
+import type { CategoryConfig } from "../config/schema"
+
+describe("Prometheus category config resolution", () => {
+  test("resolves ultrabrain category config", () => {
+    // #given
+    const categoryName = "ultrabrain"
+
+    // #when
+    const config = resolveCategoryConfig(categoryName)
+
+    // #then
+    expect(config).toBeDefined()
+    expect(config?.model).toBe("openai/gpt-5.2")
+    expect(config?.temperature).toBe(0.1)
+  })
+
+  test("resolves visual-engineering category config", () => {
+    // #given
+    const categoryName = "visual-engineering"
+
+    // #when
+    const config = resolveCategoryConfig(categoryName)
+
+    // #then
+    expect(config).toBeDefined()
+    expect(config?.model).toBe("google/gemini-3-pro-preview")
+    expect(config?.temperature).toBe(0.7)
+  })
+
+  test("user categories override default categories", () => {
+    // #given
+    const categoryName = "ultrabrain"
+    const userCategories: Record<string, CategoryConfig> = {
+      ultrabrain: {
+        model: "google/antigravity-claude-opus-4-5-thinking",
+        temperature: 0.1,
+      },
+    }
+
+    // #when
+    const config = resolveCategoryConfig(categoryName, userCategories)
+
+    // #then
+    expect(config).toBeDefined()
+    expect(config?.model).toBe("google/antigravity-claude-opus-4-5-thinking")
+    expect(config?.temperature).toBe(0.1)
+  })
+
+  test("returns undefined for unknown category", () => {
+    // #given
+    const categoryName = "nonexistent-category"
+
+    // #when
+    const config = resolveCategoryConfig(categoryName)
+
+    // #then
+    expect(config).toBeUndefined()
+  })
+
+  test("falls back to default when user category has no entry", () => {
+    // #given
+    const categoryName = "ultrabrain"
+    const userCategories: Record<string, CategoryConfig> = {
+      "visual-engineering": {
+        model: "custom/visual-model",
+      },
+    }
+
+    // #when
+    const config = resolveCategoryConfig(categoryName, userCategories)
+
+    // #then
+    expect(config).toBeDefined()
+    expect(config?.model).toBe("openai/gpt-5.2")
+    expect(config?.temperature).toBe(0.1)
+  })
+
+  test("preserves all category properties (temperature, top_p, tools, etc.)", () => {
+    // #given
+    const categoryName = "custom-category"
+    const userCategories: Record<string, CategoryConfig> = {
+      "custom-category": {
+        model: "test/model",
+        temperature: 0.5,
+        top_p: 0.9,
+        maxTokens: 32000,
+        tools: { tool1: true, tool2: false },
+      },
+    }
+
+    // #when
+    const config = resolveCategoryConfig(categoryName, userCategories)
+
+    // #then
+    expect(config).toBeDefined()
+    expect(config?.model).toBe("test/model")
+    expect(config?.temperature).toBe(0.5)
+    expect(config?.top_p).toBe(0.9)
+    expect(config?.maxTokens).toBe(32000)
+    expect(config?.tools).toEqual({ tool1: true, tool2: false })
+  })
+})
diff --git a/src/plugin-handlers/config-handler.ts b/src/plugin-handlers/config-handler.ts
index c29efa7276..b16f8fb359 100644
--- a/src/plugin-handlers/config-handler.ts
+++ b/src/plugin-handlers/config-handler.ts
@@ -24,7 +24,9 @@ import type { OhMyOpenCodeConfig } from "../config";
 import { log } from "../shared";
 import { migrateAgentConfig } from "../shared/permission-compat";
 import { PROMETHEUS_SYSTEM_PROMPT, PROMETHEUS_PERMISSION } from "../agents/prometheus-prompt";
+import { DEFAULT_CATEGORIES } from "../tools/sisyphus-task/constants";
 import type { ModelCacheState } from "../plugin-state";
+import type { CategoryConfig } from "../config/schema";
 
 export interface ConfigHandlerDeps {
   ctx: { directory: string };
@@ -32,6 +34,13 @@ export interface ConfigHandlerDeps {
   modelCacheState: ModelCacheState;
 }
 
+export function resolveCategoryConfig(
+  categoryName: string,
+  userCategories?: Record<string, CategoryConfig>
+): CategoryConfig | undefined {
+  return userCategories?.[categoryName] ?? DEFAULT_CATEGORIES[categoryName];
+}
+
 export function createConfigHandler(deps: ConfigHandlerDeps) {
   const { ctx, pluginConfig, modelCacheState } = deps;
 
@@ -173,15 +182,50 @@ export function createConfigHandler(deps: ConfigHandlerDeps) {
           planConfigWithoutName as Record<string, unknown>
         );
         const prometheusOverride =
-          pluginConfig.agents?.["Prometheus (Planner)"];
+          pluginConfig.agents?.["Prometheus (Planner)"] as
+            | (Record<string, unknown> & { category?: string; model?: string })
+            | undefined;
         const defaultModel = config.model as string | undefined;
+
+        // Resolve full category config (model, temperature, top_p, tools, etc.)
+        // Apply all category properties when category is specified, but explicit
+        // overrides (model, temperature, etc.) will take precedence during merge
+        const categoryConfig = prometheusOverride?.category
+          ? resolveCategoryConfig(
+              prometheusOverride.category,
+              pluginConfig.categories
+            )
+          : undefined;
+
         const prometheusBase = {
-          model: defaultModel ?? "anthropic/claude-opus-4-5",
+          model:
+            prometheusOverride?.model ??
+            categoryConfig?.model ??
+            defaultModel ??
+            "anthropic/claude-opus-4-5",
           mode: "primary" as const,
           prompt: PROMETHEUS_SYSTEM_PROMPT,
           permission: PROMETHEUS_PERMISSION,
           description: `${configAgent?.plan?.description ?? "Plan agent"} (Prometheus - OhMyOpenCode)`,
           color: (configAgent?.plan?.color as string) ?? "#FF6347",
+          // Apply category properties (temperature, top_p, tools, etc.)
+          ...(categoryConfig?.temperature !== undefined
+            ? { temperature: categoryConfig.temperature }
+            : {}),
+          ...(categoryConfig?.top_p !== undefined
+            ? { top_p: categoryConfig.top_p }
+            : {}),
+          ...(categoryConfig?.maxTokens !== undefined
+            ? { maxTokens: categoryConfig.maxTokens }
+            : {}),
+          ...(categoryConfig?.tools ? { tools: categoryConfig.tools } : {}),
+          ...(categoryConfig?.thinking ? { thinking: categoryConfig.thinking } : {}),
+          ...(categoryConfig?.reasoningEffort !== undefined
+            ? { reasoningEffort: categoryConfig.reasoningEffort }
+            : {}),
+          ...(categoryConfig?.textVerbosity !== undefined
+            ? { textVerbosity: categoryConfig.textVerbosity }
+            : {}),
         };
 
         agentConfig["Prometheus (Planner)"] = prometheusOverride