diff --git a/src/agents/utils.test.ts b/src/agents/utils.test.ts
index 645e0edc0..87d6db761 100644
--- a/src/agents/utils.test.ts
+++ b/src/agents/utils.test.ts
@@ -1116,7 +1116,7 @@ describe("buildAgent with category and skills", () => {
     const agent = buildAgent(source["test-agent"], TEST_MODEL)
 
     // #then - category's built-in model and skills are applied
-    expect(agent.model).toBe("openai/gpt-5.3-codex")
+    expect(agent.model).toBe("openai/gpt-5.4")
     expect(agent.variant).toBe("xhigh")
     expect(agent.prompt).toContain("Role: Designer-Turned-Developer")
     expect(agent.prompt).toContain("Task description")
@@ -1229,9 +1229,9 @@ describe("override.category expansion in createBuiltinAgents", () => {
     // #when
     const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
 
-    // #then - ultrabrain category: model=openai/gpt-5.3-codex, variant=xhigh
+    // #then - ultrabrain category: model=openai/gpt-5.4, variant=xhigh
     expect(agents.oracle).toBeDefined()
-    expect(agents.oracle.model).toBe("openai/gpt-5.3-codex")
+    expect(agents.oracle.model).toBe("openai/gpt-5.4")
     expect(agents.oracle.variant).toBe("xhigh")
   })
 
@@ -1298,9 +1298,9 @@ describe("override.category expansion in createBuiltinAgents", () => {
     // #when
     const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
 
-    // #then - ultrabrain category: model=openai/gpt-5.3-codex, variant=xhigh
+    // #then - ultrabrain category: model=openai/gpt-5.4, variant=xhigh
     expect(agents.sisyphus).toBeDefined()
-    expect(agents.sisyphus.model).toBe("openai/gpt-5.3-codex")
+    expect(agents.sisyphus.model).toBe("openai/gpt-5.4")
     expect(agents.sisyphus.variant).toBe("xhigh")
   })
 
@@ -1313,9 +1313,9 @@ describe("override.category expansion in createBuiltinAgents", () => {
     // #when
     const agents = await createBuiltinAgents([], overrides, undefined, TEST_DEFAULT_MODEL)
 
-    // #then - ultrabrain category: model=openai/gpt-5.3-codex, variant=xhigh
+    // #then - ultrabrain category: model=openai/gpt-5.4, variant=xhigh
     expect(agents.atlas).toBeDefined()
-    expect(agents.atlas.model).toBe("openai/gpt-5.3-codex")
+    expect(agents.atlas.model).toBe("openai/gpt-5.4")
     expect(agents.atlas.variant).toBe("xhigh")
   })
 
diff --git a/src/plugin-handlers/config-handler.test.ts b/src/plugin-handlers/config-handler.test.ts
index 6da6dd9b7..c3e7a91d8 100644
--- a/src/plugin-handlers/config-handler.test.ts
+++ b/src/plugin-handlers/config-handler.test.ts
@@ -557,7 +557,7 @@ describe("Prometheus category config resolution", () => {
 
     // then
     expect(config).toBeDefined()
-    expect(config?.model).toBe("openai/gpt-5.3-codex")
+    expect(config?.model).toBe("openai/gpt-5.4")
     expect(config?.variant).toBe("xhigh")
   })
 
@@ -617,7 +617,7 @@ describe("Prometheus category config resolution", () => {
 
     // then - falls back to DEFAULT_CATEGORIES
     expect(config).toBeDefined()
-    expect(config?.model).toBe("openai/gpt-5.3-codex")
+    expect(config?.model).toBe("openai/gpt-5.4")
     expect(config?.variant).toBe("xhigh")
   })