diff --git a/apps/code/src/main/services/agent/service.test.ts b/apps/code/src/main/services/agent/service.test.ts
index fe726d994..5e277e6ad 100644
--- a/apps/code/src/main/services/agent/service.test.ts
+++ b/apps/code/src/main/services/agent/service.test.ts
@@ -89,9 +89,12 @@ vi.mock("@posthog/agent/posthog-api", () => ({
 }));
 
 vi.mock("@posthog/agent/gateway-models", () => ({
+  DEFAULT_GATEWAY_MODEL: "claude-opus-4-8",
+  DEFAULT_CODEX_MODEL: "gpt-5.5",
   fetchGatewayModels: vi.fn().mockResolvedValue([]),
   formatGatewayModelName: vi.fn(),
   getProviderName: vi.fn(),
+  isBlockedModelId: vi.fn().mockReturnValue(false),
 }));
 
 vi.mock("@posthog/agent/adapters/claude/session/jsonl-hydration", () => ({
diff --git a/apps/code/src/main/services/llm-gateway/schemas.ts b/apps/code/src/main/services/llm-gateway/schemas.ts
index b14fffd25..7c569c895 100644
--- a/apps/code/src/main/services/llm-gateway/schemas.ts
+++ b/apps/code/src/main/services/llm-gateway/schemas.ts
@@ -1,3 +1,4 @@
+import { DEFAULT_GATEWAY_MODEL } from "@posthog/agent/gateway-models";
 import { z } from "zod";
 
 export const llmMessageSchema = z.object({
@@ -11,7 +12,7 @@ export const promptInput = z.object({
   system: z.string().optional(),
   messages: z.array(llmMessageSchema),
   maxTokens: z.number().optional(),
-  model: z.string().default("claude-haiku-4-5"),
+  model: z.string().default(DEFAULT_GATEWAY_MODEL),
 });
 
 export type PromptInput = z.infer<typeof promptInput>;
diff --git a/apps/code/src/main/services/llm-gateway/service.ts b/apps/code/src/main/services/llm-gateway/service.ts
index 2a6ac5a26..11813e474 100644
--- a/apps/code/src/main/services/llm-gateway/service.ts
+++ b/apps/code/src/main/services/llm-gateway/service.ts
@@ -1,3 +1,4 @@
+import { DEFAULT_GATEWAY_MODEL } from "@posthog/agent/gateway-models";
 import {
   getGatewayInvalidatePlanCacheUrl,
   getGatewayUsageUrl,
@@ -51,7 +52,7 @@ export class LlmGatewayService {
     const {
       system,
       maxTokens,
-      model = "claude-haiku-4-5",
+      model = DEFAULT_GATEWAY_MODEL,
       signal,
       timeoutMs = 60_000,
     } = options;
diff --git a/apps/code/src/renderer/api/posthogClient.test.ts b/apps/code/src/renderer/api/posthogClient.test.ts
index f684aa266..2e0f29964 100644
--- a/apps/code/src/renderer/api/posthogClient.test.ts
+++ b/apps/code/src/renderer/api/posthogClient.test.ts
@@ -115,11 +115,11 @@ describe("PostHogAPIClient", () => {
     await expect(
       client.runTaskInCloud("task-123", "feature/legacy-effort", {
         adapter: "claude",
-        model: "claude-opus-4-6",
+        model: "claude-opus-4-8",
         reasoningLevel: "minimal",
       }),
     ).rejects.toThrow(
-      "Reasoning effort 'minimal' is not supported for claude model 'claude-opus-4-6'.",
+      "Reasoning effort 'minimal' is not supported for claude model 'claude-opus-4-8'.",
     );
 
     expect(post).not.toHaveBeenCalled();
diff --git a/apps/code/src/renderer/features/message-editor/components/PromptInput.stories.tsx b/apps/code/src/renderer/features/message-editor/components/PromptInput.stories.tsx
index 9fd2f9938..bc67302db 100644
--- a/apps/code/src/renderer/features/message-editor/components/PromptInput.stories.tsx
+++ b/apps/code/src/renderer/features/message-editor/components/PromptInput.stories.tsx
@@ -15,13 +15,13 @@ const mockModelOption = {
   id: "model",
   name: "Model",
   type: "select" as const,
-  currentValue: "gpt-5.4",
+  currentValue: "gpt-5.5",
   options: [
     {
       group: "recommended",
       name: "Recommended",
       options: [
-        { value: "gpt-5.4", name: "GPT 5.4" },
+        { value: "gpt-5.5", name: "gpt-5.5" },
         { value: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
       ],
     },
@@ -29,9 +29,8 @@ const mockModelOption = {
       group: "other",
       name: "Other",
       options: [
-        { value: "claude-opus-4-6", name: "Claude Opus 4.6" },
+        { value: "claude-opus-4-8", name: "Claude Opus 4.8" },
         { value: "o3-pro", name: "o3-pro" },
-        { value: "claude-haiku-4-5", name: "Claude Haiku 4.5" },
       ],
     },
   ],
diff --git a/apps/mobile/src/features/inbox/components/TinderView.tsx b/apps/mobile/src/features/inbox/components/TinderView.tsx
index 7eb2b5fd9..ae468b8c4 100644
--- a/apps/mobile/src/features/inbox/components/TinderView.tsx
+++ b/apps/mobile/src/features/inbox/components/TinderView.tsx
@@ -17,6 +17,7 @@ import {
 } from "react-native-safe-area-context";
 import { MarkdownText } from "@/features/chat/components/MarkdownText";
 import { createTask, runTaskInCloud } from "@/features/tasks/api";
+import { DEFAULT_MODEL } from "@/features/tasks/composer/options";
 import type {
   CreateTaskOptions,
   RepositoryOption,
@@ -206,7 +207,7 @@ export function TinderView({
         await runTaskInCloud(task.id, {
           pendingUserMessage: prompt,
           runtimeAdapter: "claude",
-          model: "claude-opus-4-7",
+          model: DEFAULT_MODEL,
           initialPermissionMode: "plan",
           runSource: "signal_report",
           signalReportId: report.id,
diff --git a/apps/mobile/src/features/tasks/api.ts b/apps/mobile/src/features/tasks/api.ts
index d09d2afc5..2375aa620 100644
--- a/apps/mobile/src/features/tasks/api.ts
+++ b/apps/mobile/src/features/tasks/api.ts
@@ -406,7 +406,7 @@ export interface RunTaskInCloudOptions {
   mode?: "interactive" | "background";
   /** Adapter to use on the cloud runner. Currently only "claude" on mobile. */
   runtimeAdapter?: "claude" | "codex";
-  /** Gateway model ID, e.g. "claude-opus-4-7". */
+  /** Gateway model ID, e.g. "claude-opus-4-8". */
   model?: string;
   /** Reasoning effort: "low" | "medium" | "high" (model-dependent). */
   reasoningEffort?: string;
diff --git a/apps/mobile/src/features/tasks/composer/options.ts b/apps/mobile/src/features/tasks/composer/options.ts
index 885554cf3..6e40ead38 100644
--- a/apps/mobile/src/features/tasks/composer/options.ts
+++ b/apps/mobile/src/features/tasks/composer/options.ts
@@ -37,8 +37,8 @@ export interface ModelOption {
 
 export const MODELS: ModelOption[] = [
   {
-    value: "claude-opus-4-7",
-    label: "Claude Opus 4.7",
+    value: "claude-opus-4-8",
+    label: "Claude Opus 4.8",
     description: "Most capable, slower",
     supportsReasoning: true,
   },
@@ -48,12 +48,6 @@ export const MODELS: ModelOption[] = [
     description: "Balanced",
     supportsReasoning: true,
   },
-  {
-    value: "claude-haiku-4-5",
-    label: "Claude Haiku 4.5",
-    description: "Fastest",
-    supportsReasoning: false,
-  },
 ];
 
 export const REASONING_LEVELS: {
@@ -68,7 +62,7 @@ export const REASONING_LEVELS: {
 ];
 
 export const DEFAULT_EXECUTION_MODE: ExecutionMode = "plan";
-export const DEFAULT_MODEL = "claude-opus-4-7";
+export const DEFAULT_MODEL = "claude-opus-4-8";
 export const DEFAULT_REASONING: ReasoningEffort = "high";
 
 export function modelLabel(value: string): string {
diff --git a/packages/agent/src/adapters/claude/claude-agent.ts b/packages/agent/src/adapters/claude/claude-agent.ts
index 7c960d4f7..cf900998d 100644
--- a/packages/agent/src/adapters/claude/claude-agent.ts
+++ b/packages/agent/src/adapters/claude/claude-agent.ts
@@ -1182,7 +1182,7 @@ export class ClaudeAcpAgent extends BaseAcpAgent {
 
     // For model options, fall back to alias resolution when exact match fails.
     // This lets callers use human-friendly aliases like "opus" or "sonnet"
-    // instead of full model IDs like "claude-opus-4-6".
+    // instead of full model IDs like "claude-opus-4-8".
     if (!validValue && params.configId === "model") {
       const resolved = resolveModelPreference(params.value, allValues);
       if (resolved) {
diff --git a/packages/agent/src/adapters/claude/session/jsonl-hydration.test.ts b/packages/agent/src/adapters/claude/session/jsonl-hydration.test.ts
index 3fad3f780..9d42cfe2a 100644
--- a/packages/agent/src/adapters/claude/session/jsonl-hydration.test.ts
+++ b/packages/agent/src/adapters/claude/session/jsonl-hydration.test.ts
@@ -376,7 +376,7 @@ describe("conversationTurnsToJsonlEntries", () => {
       { type: "text", text: "running" },
     ]);
     expect(conv[0].message.stop_reason).toBeNull();
-    expect(conv[0].message.model).toBe("claude-opus-4-6");
+    expect(conv[0].message.model).toBe("claude-opus-4-8");
     expect(conv[0].message.id).toMatch(/^msg_01[A-Za-z0-9]{24}$/);
 
     expect(conv[1].type).toBe("assistant");
@@ -490,13 +490,13 @@ describe("conversationTurnsToJsonlEntries", () => {
         { role: "user", content: [{ type: "text", text: "hi" }] },
         { role: "assistant", content: [{ type: "text", text: "hello" }] },
       ],
-      { sessionId: "s", cwd: "/", model: "claude-opus-4-6", version: "3.0.0" },
+      { sessionId: "s", cwd: "/", model: "claude-opus-4-7", version: "3.0.0" },
     );
 
     const conv = parseConversationEntries(lines);
     expect(conv[0].version).toBe("3.0.0");
     expect(conv[1].version).toBe("3.0.0");
-    expect(conv[1].message.model).toBe("claude-opus-4-6");
+    expect(conv[1].message.model).toBe("claude-opus-4-7");
   });
 
   it("passes gitBranch, slug and permissionMode from config", () => {
@@ -728,7 +728,7 @@ describe("end-to-end: S3 log entries -> JSONL output", () => {
     // All assistant blocks in same turn share message.id
     expect(msg1.id).toBe(msg2.id);
     expect(msg2.id).toBe(msg3.id);
-    expect(msg3.model).toBe("claude-opus-4-6");
+    expect(msg3.model).toBe("claude-opus-4-8");
     expect(msg3.id).toMatch(/^msg_01[A-Za-z0-9]{24}$/);
 
     // Verify Bash tool_result entry
diff --git a/packages/agent/src/adapters/claude/session/jsonl-hydration.ts b/packages/agent/src/adapters/claude/session/jsonl-hydration.ts
index 16d1a54ce..14b39a71b 100644
--- a/packages/agent/src/adapters/claude/session/jsonl-hydration.ts
+++ b/packages/agent/src/adapters/claude/session/jsonl-hydration.ts
@@ -3,6 +3,7 @@ import * as fs from "node:fs/promises";
 import * as os from "node:os";
 import * as path from "node:path";
 import type { ContentBlock } from "@agentclientprotocol/sdk";
+import { DEFAULT_GATEWAY_MODEL } from "../../../gateway-models";
 import type { PostHogAPIClient } from "../../../posthog-api";
 import type { StoredEntry } from "../../../types";
 import { supports1MContext } from "./models";
@@ -312,7 +313,7 @@ export function conversationTurnsToJsonlEntries(
 ): string[] {
   const lines: string[] = [];
   let parentUuid: string | null = null;
-  const model = config.model ?? "claude-opus-4-6";
+  const model = config.model ?? DEFAULT_GATEWAY_MODEL;
   const version = config.version ?? "2.1.63";
   const gitBranch = config.gitBranch ?? "";
   const slug = config.slug ?? generateSlug();
diff --git a/packages/agent/src/adapters/claude/session/model-config.test.ts b/packages/agent/src/adapters/claude/session/model-config.test.ts
index 1225885aa..98b0b2ddf 100644
--- a/packages/agent/src/adapters/claude/session/model-config.test.ts
+++ b/packages/agent/src/adapters/claude/session/model-config.test.ts
@@ -15,7 +15,7 @@ const rawModelOptions = {
 describe("applyAvailableModelsAllowlist", () => {
   it("falls back to the unfiltered gateway list when every allowlisted model is unknown", () => {
     expect(
-      applyAvailableModelsAllowlist(rawModelOptions, ["claude-opus-4-5"]),
+      applyAvailableModelsAllowlist(rawModelOptions, ["claude-unknown-model"]),
     ).toEqual(rawModelOptions);
   });
 
diff --git a/packages/agent/src/adapters/claude/session/models.test.ts b/packages/agent/src/adapters/claude/session/models.test.ts
index 724c4fe73..73a271721 100644
--- a/packages/agent/src/adapters/claude/session/models.test.ts
+++ b/packages/agent/src/adapters/claude/session/models.test.ts
@@ -14,30 +14,41 @@ describe("toSdkModelId", () => {
     expect(toSdkModelId("claude-opus-4-7")).toBe("opus");
     expect(toSdkModelId("claude-opus-4-8")).toBe("opus");
     expect(toSdkModelId("claude-sonnet-4-6")).toBe("sonnet");
-    expect(toSdkModelId("claude-haiku-4-5")).toBe("haiku");
   });
 
   it("passes unknown IDs through unchanged", () => {
     expect(toSdkModelId("custom-model")).toBe("custom-model");
   });
+
+  it("passes deprecated gateway IDs through unchanged", () => {
+    expect(toSdkModelId("claude-opus-4-6")).toBe("claude-opus-4-6");
+    expect(toSdkModelId("claude-sonnet-4-5")).toBe("claude-sonnet-4-5");
+    expect(toSdkModelId("claude-haiku-4-5")).toBe("claude-haiku-4-5");
+  });
 });
 
 describe("model capability flags", () => {
   it("flags 1M context support", () => {
+    expect(supports1MContext("claude-opus-4-6")).toBe(false);
     expect(supports1MContext("claude-opus-4-7")).toBe(true);
     expect(supports1MContext("claude-sonnet-4-6")).toBe(true);
     expect(supports1MContext("claude-haiku-4-5")).toBe(false);
   });
 
   it("flags effort support and xhigh-effort support", () => {
-    expect(supportsEffort("claude-opus-4-5")).toBe(true);
+    expect(supportsEffort("claude-opus-4-5")).toBe(false);
+    expect(supportsEffort("claude-opus-4-6")).toBe(false);
     expect(supportsXhighEffort("claude-opus-4-7")).toBe(true);
-    expect(supportsXhighEffort("claude-opus-4-5")).toBe(false);
+    expect(supportsXhighEffort("claude-opus-4-6")).toBe(false);
     expect(supportsEffort("claude-haiku-4-5")).toBe(false);
   });
 
-  it("excludes MCP injection only for Haiku", () => {
+  it("allows MCP injection for supported Claude models", () => {
     expect(supportsMcpInjection("claude-opus-4-7")).toBe(true);
+    expect(supportsMcpInjection("claude-sonnet-4-6")).toBe(true);
+  });
+
+  it("keeps deprecated Haiku sessions excluded from MCP injection", () => {
     expect(supportsMcpInjection("claude-haiku-4-5")).toBe(false);
   });
 });
@@ -45,10 +56,11 @@ describe("model capability flags", () => {
 describe("getEffortOptions", () => {
   it("returns null for models without effort support", () => {
     expect(getEffortOptions("claude-haiku-4-5")).toBeNull();
+    expect(getEffortOptions("claude-opus-4-6")).toBeNull();
   });
 
   it("returns low/medium/high for effort-supporting models", () => {
-    const opts = getEffortOptions("claude-opus-4-5");
+    const opts = getEffortOptions("claude-sonnet-4-6");
     expect(opts?.map((o) => o.value)).toEqual(["low", "medium", "high"]);
   });
 
@@ -68,9 +80,7 @@ describe("resolveModelPreference", () => {
   const options = [
     { value: "claude-opus-4-8", name: "Claude Opus 4.8" },
     { value: "claude-opus-4-7", name: "Claude Opus 4.7" },
-    { value: "claude-opus-4-6", name: "Claude Opus 4.6" },
     { value: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
-    { value: "claude-haiku-4-5", name: "Claude Haiku 4.5" },
   ];
 
   it("returns null for empty preference", () => {
@@ -85,8 +95,8 @@ describe("resolveModelPreference", () => {
   });
 
   it("matches case-insensitively on display name", () => {
-    expect(resolveModelPreference("claude haiku 4.5", options)).toBe(
-      "claude-haiku-4-5",
+    expect(resolveModelPreference("claude sonnet 4.6", options)).toBe(
+      "claude-sonnet-4-6",
     );
   });
 
@@ -100,11 +110,11 @@ describe("resolveModelPreference", () => {
 
   it("refuses cross-version alias matches", () => {
     const optionsWithAlias = [
-      { value: "opus", name: "Claude Opus 4.7" },
-      { value: "claude-opus-4-6", name: "Claude Opus 4.6" },
+      { value: "opus", name: "Claude Opus 4.8" },
+      { value: "claude-opus-4-7", name: "Claude Opus 4.7" },
     ];
-    expect(resolveModelPreference("claude-opus-4-6", optionsWithAlias)).toBe(
-      "claude-opus-4-6",
+    expect(resolveModelPreference("claude-opus-4-7", optionsWithAlias)).toBe(
+      "claude-opus-4-7",
     );
   });
 
diff --git a/packages/agent/src/adapters/claude/session/models.ts b/packages/agent/src/adapters/claude/session/models.ts
index 6d8c73199..e98ce08b4 100644
--- a/packages/agent/src/adapters/claude/session/models.ts
+++ b/packages/agent/src/adapters/claude/session/models.ts
@@ -1,13 +1,9 @@
 export const DEFAULT_MODEL = "opus";
 
 const GATEWAY_TO_SDK_MODEL: Record<string, string> = {
-  "claude-opus-4-5": "opus",
-  "claude-opus-4-6": "opus",
   "claude-opus-4-7": "opus",
   "claude-opus-4-8": "opus",
-  "claude-sonnet-4-5": "sonnet",
   "claude-sonnet-4-6": "sonnet",
-  "claude-haiku-4-5": "haiku",
 };
 
 export function toSdkModelId(modelId: string): string {
@@ -15,7 +11,6 @@ export function toSdkModelId(modelId: string): string {
 }
 
 const MODELS_WITH_1M_CONTEXT = new Set([
-  "claude-opus-4-6",
   "claude-opus-4-7",
   "claude-opus-4-8",
   "claude-sonnet-4-6",
@@ -26,15 +21,12 @@ export function supports1MContext(modelId: string): boolean {
 }
 
 const MODELS_WITH_EFFORT = new Set([
-  "claude-opus-4-5",
-  "claude-opus-4-6",
   "claude-opus-4-7",
   "claude-opus-4-8",
   "claude-sonnet-4-6",
 ]);
 
 const MODELS_WITH_XHIGH_EFFORT = new Set([
-  "claude-opus-4-6",
   "claude-opus-4-7",
   "claude-opus-4-8",
 ]);
@@ -78,7 +70,7 @@ export function getEffortOptions(modelId: string): EffortOption[] | null {
 }
 
 // Model alias resolution — lets callers use human-friendly aliases like
-// "opus" or "sonnet" instead of full model IDs like "claude-opus-4-6".
+// "opus" or "sonnet" instead of full model IDs like "claude-opus-4-8".
 
 const MODEL_CONTEXT_HINT_PATTERN = /\[(\d+m)\]$/i;
 
@@ -112,8 +104,8 @@ interface ModelOption {
 }
 
 // Captures a model family version such as `4-6` or `4.7` so we can keep
-// `claude-opus-4-6` from being copied onto the SDK's `opus` alias when that
-// alias currently resolves to a different family version (e.g. Opus 4.7).
+// `claude-opus-4-7` from being copied onto the SDK's `opus` alias when that
+// alias currently resolves to a different family version (e.g. Opus 4.8).
 const MODEL_FAMILY_VERSION_PATTERN = /\b(\d+)[-.](\d+)\b/;
 
 function extractModelFamilyVersion(s: string | undefined): string | null {
diff --git a/packages/agent/src/adapters/claude/session/options.ts b/packages/agent/src/adapters/claude/session/options.ts
index 610a7a257..b3c2683a7 100644
--- a/packages/agent/src/adapters/claude/session/options.ts
+++ b/packages/agent/src/adapters/claude/session/options.ts
@@ -183,7 +183,7 @@ function buildHooks(
 }
 
 /**
- * Read-only Haiku-powered exploration agent. Registered under the `ph-explore`
+ * Read-only exploration agent. Registered under the `ph-explore`
  * name rather than `Explore` to work around a Claude Agent SDK bug where
  * `options.agents` cannot shadow built-in agent definitions. The
  * `createSubagentRewriteHook` rewrites `subagent_type: "Explore"` to
diff --git a/packages/agent/src/adapters/codex/models.test.ts b/packages/agent/src/adapters/codex/models.test.ts
new file mode 100644
index 000000000..b31a039ac
--- /dev/null
+++ b/packages/agent/src/adapters/codex/models.test.ts
@@ -0,0 +1,8 @@
+import { describe, expect, it } from "vitest";
+import { formatCodexModelName } from "./models";
+
+describe("formatCodexModelName", () => {
+  it("uses raw lowercase model ids", () => {
+    expect(formatCodexModelName("GPT-5.5")).toBe("gpt-5.5");
+  });
+});
diff --git a/packages/agent/src/adapters/codex/models.ts b/packages/agent/src/adapters/codex/models.ts
index 635e631c7..3264974fc 100644
--- a/packages/agent/src/adapters/codex/models.ts
+++ b/packages/agent/src/adapters/codex/models.ts
@@ -21,21 +21,8 @@ export function getReasoningEffortOptions(
   return CODEX_REASONING_EFFORT_OPTIONS;
 }
 
-const CODEX_ACRONYMS: Record<string, string> = {
-  gpt: "GPT",
-};
-
 export function formatCodexModelName(value: string): string {
-  const normalized = value.replace(/(\d)-(\d)/g, "$1.$2");
-  return normalized
-    .split("-")
-    .map((part) => {
-      const lower = part.toLowerCase();
-      if (CODEX_ACRONYMS[lower]) return CODEX_ACRONYMS[lower];
-      if (/^[0-9.]+$/.test(part)) return part;
-      return part.charAt(0).toUpperCase() + part.slice(1).toLowerCase();
-    })
-    .join("-");
+  return value.toLowerCase();
 }
 
 export function normalizeCodexConfigOptions(
diff --git a/packages/agent/src/agent.ts b/packages/agent/src/agent.ts
index e4b3d9bfe..4456e63be 100644
--- a/packages/agent/src/agent.ts
+++ b/packages/agent/src/agent.ts
@@ -3,10 +3,10 @@ import {
   type InProcessAcpConnection,
 } from "./adapters/acp-connection";
 import {
-  BLOCKED_MODELS,
   DEFAULT_CODEX_MODEL,
   DEFAULT_GATEWAY_MODEL,
   fetchModelsList,
+  isBlockedModelId,
 } from "./gateway-models";
 import { PostHogAPIClient, type TaskRunUpdate } from "./posthog-api";
 import { SessionLogWriter } from "./session-log-writer";
@@ -84,7 +84,7 @@ export class Agent {
 
     let allowedModelIds: Set<string> | undefined;
     let sanitizedModel =
-      options.model && !BLOCKED_MODELS.has(options.model)
+      options.model && !isBlockedModelId(options.model)
         ? options.model
         : undefined;
     if (options.adapter === "codex" && gatewayConfig) {
@@ -93,7 +93,7 @@ export class Agent {
       });
       const codexModelIds = models
         .filter((model) => {
-          if (BLOCKED_MODELS.has(model.id)) return false;
+          if (isBlockedModelId(model.id)) return false;
           if (model.owned_by) {
             return model.owned_by === "openai";
           }
diff --git a/packages/agent/src/gateway-models.test.ts b/packages/agent/src/gateway-models.test.ts
new file mode 100644
index 000000000..42f4ac45c
--- /dev/null
+++ b/packages/agent/src/gateway-models.test.ts
@@ -0,0 +1,57 @@
+import { describe, expect, it } from "vitest";
+import { formatGatewayModelName, isBlockedModelId } from "./gateway-models";
+
+describe("formatGatewayModelName", () => {
+  it("keeps Claude models in friendly title case", () => {
+    expect(
+      formatGatewayModelName({
+        id: "claude-opus-4-8",
+        owned_by: "anthropic",
+        context_window: 200000,
+        supports_streaming: true,
+        supports_vision: true,
+      }),
+    ).toBe("Claude Opus 4.8");
+  });
+
+  it("formats OpenAI models as raw lowercase model ids", () => {
+    expect(
+      formatGatewayModelName({
+        id: "GPT-5.5",
+        owned_by: "openai",
+        context_window: 200000,
+        supports_streaming: true,
+        supports_vision: true,
+      }),
+    ).toBe("gpt-5.5");
+  });
+
+  it("strips the openai/ prefix from OpenAI model ids", () => {
+    expect(
+      formatGatewayModelName({
+        id: "openai/gpt-5.5",
+        owned_by: "openai",
+        context_window: 200000,
+        supports_streaming: true,
+        supports_vision: true,
+      }),
+    ).toBe("gpt-5.5");
+  });
+
+  it("blocks deprecated Claude gateway models", () => {
+    expect(isBlockedModelId("claude-opus-4-5")).toBe(true);
+    expect(isBlockedModelId("claude-opus-4-6")).toBe(true);
+    expect(isBlockedModelId("claude-sonnet-4-5")).toBe(true);
+    expect(isBlockedModelId("claude-haiku-4-5")).toBe(true);
+    expect(isBlockedModelId("ANTHROPIC/CLAUDE-HAIKU-4-5")).toBe(true);
+  });
+
+  it("blocks deprecated Codex gateway models", () => {
+    expect(isBlockedModelId("gpt-5.2")).toBe(true);
+    expect(isBlockedModelId("gpt-5.3")).toBe(true);
+    expect(isBlockedModelId("gpt-5.3-codex")).toBe(true);
+    expect(isBlockedModelId("openai/gpt-5.2")).toBe(true);
+    expect(isBlockedModelId("OPENAI/GPT-5.3")).toBe(true);
+    expect(isBlockedModelId("OPENAI/GPT-5.3-CODEX")).toBe(true);
+  });
+});
diff --git a/packages/agent/src/gateway-models.ts b/packages/agent/src/gateway-models.ts
index 01193777b..b8aafc78f 100644
--- a/packages/agent/src/gateway-models.ts
+++ b/packages/agent/src/gateway-models.ts
@@ -15,11 +15,32 @@ export interface FetchGatewayModelsOptions {
   gatewayUrl: string;
 }
 
-export const DEFAULT_GATEWAY_MODEL = "claude-opus-4-7";
-
-export const DEFAULT_CODEX_MODEL = "gpt-5.4";
-
-export const BLOCKED_MODELS = new Set(["gpt-5-mini", "openai/gpt-5-mini"]);
+export const DEFAULT_GATEWAY_MODEL = "claude-opus-4-8";
+
+export const DEFAULT_CODEX_MODEL = "gpt-5.5";
+
+const BLOCKED_MODELS = new Set([
+  "gpt-5-mini",
+  "openai/gpt-5-mini",
+  "gpt-5.2",
+  "openai/gpt-5.2",
+  "gpt-5.3",
+  "openai/gpt-5.3",
+  "gpt-5.3-codex",
+  "openai/gpt-5.3-codex",
+  "claude-opus-4-5",
+  "anthropic/claude-opus-4-5",
+  "claude-opus-4-6",
+  "anthropic/claude-opus-4-6",
+  "claude-sonnet-4-5",
+  "anthropic/claude-sonnet-4-5",
+  "claude-haiku-4-5",
+  "anthropic/claude-haiku-4-5",
+]);
+
+export function isBlockedModelId(modelId: string): boolean {
+  return BLOCKED_MODELS.has(modelId.toLowerCase());
+}
 
 type ModelsListResponse =
   | {
@@ -62,7 +83,7 @@ export async function fetchGatewayModels(
     }
 
     const data = (await response.json()) as GatewayModelsResponse;
-    const models = (data.data ?? []).filter((m) => !BLOCKED_MODELS.has(m.id));
+    const models = (data.data ?? []).filter((m) => !isBlockedModelId(m.id));
     gatewayModelsCache = {
       models,
       expiry: Date.now() + CACHE_TTL,
@@ -129,6 +150,7 @@ export async function fetchModelsList(
     for (const model of models) {
       const id = model?.id ? String(model.id) : "";
       if (!id) continue;
+      if (isBlockedModelId(id)) continue;
       results.push({ id, owned_by: model?.owned_by });
     }
     modelsListCache = {
@@ -155,9 +177,22 @@ export function getProviderName(ownedBy: string): string {
 const PROVIDER_PREFIXES = ["anthropic/", "openai/", "google-vertex/"];
 
 export function formatGatewayModelName(model: GatewayModel): string {
+  if (isOpenAIModel(model)) {
+    return stripProviderPrefix(model.id).toLowerCase();
+  }
+
   return formatModelId(model.id);
 }
 
+function stripProviderPrefix(modelId: string): string {
+  for (const prefix of PROVIDER_PREFIXES) {
+    if (modelId.startsWith(prefix)) {
+      return modelId.slice(prefix.length);
+    }
+  }
+  return modelId;
+}
+
 export function formatModelId(modelId: string): string {
   let cleanId = modelId;
   for (const prefix of PROVIDER_PREFIXES) {
diff --git a/packages/agent/src/test/mocks/claude-sdk.ts b/packages/agent/src/test/mocks/claude-sdk.ts
index d2ec6c797..e54cb05cc 100644
--- a/packages/agent/src/test/mocks/claude-sdk.ts
+++ b/packages/agent/src/test/mocks/claude-sdk.ts
@@ -244,7 +244,7 @@ export function createInitMessage(sessionId = "test-session"): SDKMessage {
     cwd: "/tmp",
     tools: [],
     mcp_servers: [],
-    model: "claude-sonnet-4-5-20250929",
+    model: "claude-sonnet-4-6",
     permissionMode: "default",
     slash_commands: [],
     output_style: "default",
diff --git a/packages/agent/src/test/mocks/msw-handlers.ts b/packages/agent/src/test/mocks/msw-handlers.ts
index efbb865f2..c73fe912c 100644
--- a/packages/agent/src/test/mocks/msw-handlers.ts
+++ b/packages/agent/src/test/mocks/msw-handlers.ts
@@ -29,14 +29,14 @@ export function createPostHogHandlers(options: PostHogHandlersOptions = {}) {
         object: "list",
         data: [
           {
-            id: "claude-opus-4-7",
+            id: "claude-opus-4-8",
             owned_by: "anthropic",
             context_window: 200000,
             supports_streaming: true,
             supports_vision: true,
           },
           {
-            id: "gpt-5.4",
+            id: "gpt-5.5",
             owned_by: "openai",
             context_window: 200000,
             supports_streaming: true,