diff --git a/src/shared/model-requirements.ts b/src/shared/model-requirements.ts
index 36771b4bc..56b53d98c 100644
--- a/src/shared/model-requirements.ts
+++ b/src/shared/model-requirements.ts
@@ -49,7 +49,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       {
         providers: ["openai", "github-copilot", "venice", "opencode", "vercel"],
-        model: "gpt-5.4",
+        model: "gpt-5.5",
         variant: "medium",
       },
     ],
@@ -59,7 +59,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       {
         providers: ["openai", "github-copilot", "opencode", "vercel"],
-        model: "gpt-5.4",
+        model: "gpt-5.5",
         variant: "high",
       },
       {
@@ -225,7 +225,7 @@ export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       {
         providers: ["openai", "github-copilot", "venice", "opencode", "vercel"],
-        model: "gpt-5.4",
+        model: "gpt-5.5",
         variant: "medium",
       },
       {
diff --git a/src/tools/delegate-task/openai-categories.ts b/src/tools/delegate-task/openai-categories.ts
index 028ade55e..ff0eb40bb 100644
--- a/src/tools/delegate-task/openai-categories.ts
+++ b/src/tools/delegate-task/openai-categories.ts
@@ -103,7 +103,7 @@ export const OPENAI_CATEGORIES: BuiltinCategoryDefinition[] = [
   },
   {
     name: "deep",
-    config: { model: "openai/gpt-5.4", variant: "medium" },
+    config: { model: "openai/gpt-5.5", variant: "medium" },
     description: "Goal-oriented autonomous problem-solving. Thorough research before action. For hairy problems requiring deep understanding.",
     promptAppend: DEEP_CATEGORY_PROMPT_APPEND,
   },