diff --git a/packages/adapters/codex-local/src/index.test.ts b/packages/adapters/codex-local/src/index.test.ts
index a40331e778..213edf017e 100644
--- a/packages/adapters/codex-local/src/index.test.ts
+++ b/packages/adapters/codex-local/src/index.test.ts
@@ -1,9 +1,18 @@
 import { describe, expect, it } from "vitest";
-import { DEFAULT_CODEX_LOCAL_MODEL, models } from "./index.js";
+import { DEFAULT_CODEX_LOCAL_MODEL, isCodexLocalFastModeSupported, models } from "./index.js";
 
 describe("codex local adapter metadata", () => {
-  it("does not advertise the ChatGPT-unsupported gpt-5.3-codex model as a default option", () => {
-    expect(DEFAULT_CODEX_LOCAL_MODEL).toBe("gpt-5.5");
-    expect(models.map((model) => model.id)).not.toContain("gpt-5.3-codex");
+  it("advertises current GPT-5.6 Codex-capable OpenAI models by default", () => {
+    const modelIds = models.map((model) => model.id);
+
+    expect(DEFAULT_CODEX_LOCAL_MODEL).toBe("gpt-5.6");
+    expect(modelIds.slice(0, 4)).toEqual([
+      "gpt-5.6",
+      "gpt-5.6-sol",
+      "gpt-5.6-terra",
+      "gpt-5.6-luna",
+    ]);
+    expect(isCodexLocalFastModeSupported(DEFAULT_CODEX_LOCAL_MODEL)).toBe(true);
+    expect(modelIds).not.toContain("gpt-5.3-codex");
   });
 });
diff --git a/packages/adapters/codex-local/src/index.ts b/packages/adapters/codex-local/src/index.ts
index 6af08521c2..c5658d2b05 100644
--- a/packages/adapters/codex-local/src/index.ts
+++ b/packages/adapters/codex-local/src/index.ts
@@ -5,9 +5,9 @@ export const label = "Codex";
 
 export const SANDBOX_INSTALL_COMMAND = "npm install -g @openai/codex";
 
-export const DEFAULT_CODEX_LOCAL_MODEL = "gpt-5.5";
+export const DEFAULT_CODEX_LOCAL_MODEL = "gpt-5.6";
 export const DEFAULT_CODEX_LOCAL_BYPASS_APPROVALS_AND_SANDBOX = true;
-export const CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS = ["gpt-5.5", "gpt-5.4"] as const;
+export const CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS = ["gpt-5.6", "gpt-5.5", "gpt-5.4"] as const;
 
 function normalizeModelId(model: string | null | undefined): string {
   return typeof model === "string" ? model.trim() : "";
@@ -28,9 +28,8 @@ export function isCodexLocalFastModeSupported(model: string | null | undefined):
   if (isCodexLocalManualModel(model)) return true;
   const normalizedModel = typeof model === "string" ? model.trim() : "";
   // Empty means we're omitting --model so the Codex CLI picks its own default.
-  // On subscription auth that's gpt-5.5 (fast-mode capable); manual model IDs
-  // are also treated as supported. Match that policy: pass the fast-mode
-  // overrides through and let the CLI reject them if the chosen model can't use them.
+  // Manual model IDs are also treated as supported: pass the fast-mode overrides
+  // through and let the CLI reject them if the chosen model can't use them.
   if (!normalizedModel) return true;
   return CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS.includes(
     normalizedModel as (typeof CODEX_LOCAL_FAST_MODE_SUPPORTED_MODELS)[number],
@@ -39,6 +38,9 @@ export function isCodexLocalFastModeSupported(model: string | null | undefined):
 
 export const models = [
   { id: DEFAULT_CODEX_LOCAL_MODEL, label: DEFAULT_CODEX_LOCAL_MODEL },
+  { id: "gpt-5.6-sol", label: "gpt-5.6-sol" },
+  { id: "gpt-5.6-terra", label: "gpt-5.6-terra" },
+  { id: "gpt-5.6-luna", label: "gpt-5.6-luna" },
   { id: "gpt-5.4", label: "gpt-5.4" },
   { id: "gpt-5.4-mini", label: "gpt-5.4-mini" },
   { id: "gpt-5.3-codex-spark", label: "gpt-5.3-codex-spark" },
@@ -77,7 +79,7 @@ Core fields:
 - modelReasoningEffort (string, optional): reasoning effort override (minimal|low|medium|high|xhigh) passed via -c model_reasoning_effort=...
 - promptTemplate (string, optional): run prompt template
 - search (boolean, optional): run codex with --search
-- fastMode (boolean, optional): enable Codex Fast mode; supported on GPT-5.5, GPT-5.4 and passed through for manual model IDs
+- fastMode (boolean, optional): enable Codex Fast mode; supported on GPT-5.6, GPT-5.5, GPT-5.4 and passed through for manual model IDs
 - dangerouslyBypassApprovalsAndSandbox (boolean, optional): run with bypass flag
 - command (string, optional): defaults to "codex"
 - extraArgs (string[], optional): additional CLI args
@@ -102,7 +104,7 @@ Notes:
 - Paperclip injects desired local skills into the effective CODEX_HOME/skills/ directory at execution time so Codex can discover "$paperclip" and related skills without polluting the project working directory. For new and updated agents, Paperclip assigns an isolated managed home at ~/.paperclip/instances/<id>/companies/<companyId>/agents/<agentId>/codex-home/skills/; when CODEX_HOME is explicitly overridden in adapter config, that override is used instead.
 - New and updated codex_local agents persist an empty OPENAI_API_KEY override by default so a host-level OPENAI_API_KEY cannot leak into Codex runs through process inheritance. Explicit CODEX_HOME overrides must not point at the shared company codex-home, $CODEX_HOME, or ~/.codex.
 - Some model/tool combinations reject certain effort levels (for example minimal with web search enabled).
-- Fast mode is supported on GPT-5.5, GPT-5.4 and manual model IDs. When enabled for those models, Paperclip applies \`service_tier="fast"\` and \`features.fast_mode=true\`.
+- Fast mode is supported on GPT-5.6, GPT-5.5, GPT-5.4 and manual model IDs. When enabled for those models, Paperclip applies \`service_tier="fast"\` and \`features.fast_mode=true\`.
 - When Paperclip realizes a workspace/runtime for a run, it injects PAPERCLIP_WORKSPACE_* and PAPERCLIP_RUNTIME_* env vars for agent-side tooling.
 - Codex ACP is the preferred auto lane when Node >=22.13.0 and the Codex ACP server are available. It reuses shared ACP prompt/runtime guidance, selected skill materialization into CODEX_HOME/skills, model/reasoning/fast-mode session config, and existing quota-window reporting. Auto selection falls back to CLI when ACP prerequisites are unavailable; explicit engine="acp" fails loudly.
 `;
diff --git a/packages/adapters/codex-local/src/server/codex-args.test.ts b/packages/adapters/codex-local/src/server/codex-args.test.ts
index 53a86a3455..e0843ca2e6 100644
--- a/packages/adapters/codex-local/src/server/codex-args.test.ts
+++ b/packages/adapters/codex-local/src/server/codex-args.test.ts
@@ -98,7 +98,7 @@ describe("buildCodexExecArgs", () => {
     expect(result.fastModeRequested).toBe(true);
     expect(result.fastModeApplied).toBe(false);
     expect(result.fastModeIgnoredReason).toContain(
-      "currently only supported on gpt-5.5, gpt-5.4 or manually configured model IDs",
+      "currently only supported on gpt-5.6, gpt-5.5, gpt-5.4 or manually configured model IDs",
     );
     expect(result.args).toEqual([
       "exec",
diff --git a/server/src/__tests__/adapter-models.test.ts b/server/src/__tests__/adapter-models.test.ts
index e82eec5c36..2db24439dd 100644
--- a/server/src/__tests__/adapter-models.test.ts
+++ b/server/src/__tests__/adapter-models.test.ts
@@ -48,7 +48,10 @@ describe("adapter model listing", () => {
     const models = await listAdapterModels("codex_local");
 
     expect(models).toEqual(codexFallbackModels);
-    expect(models.some((model) => model.id === "gpt-5.5")).toBe(true);
+    expect(models.some((model) => model.id === "gpt-5.6")).toBe(true);
+    expect(models.some((model) => model.id === "gpt-5.6-sol")).toBe(true);
+    expect(models.some((model) => model.id === "gpt-5.6-terra")).toBe(true);
+    expect(models.some((model) => model.id === "gpt-5.6-luna")).toBe(true);
     expect(fetchSpy).not.toHaveBeenCalled();
   });
 
@@ -155,7 +158,7 @@ describe("adapter model listing", () => {
       .mockResolvedValueOnce({
         ok: true,
         json: async () => ({
-          data: [{ id: "gpt-5.5" }],
+          data: [{ id: "gpt-5.6-terra" }],
         }),
       } as Response);
 
@@ -164,7 +167,8 @@ describe("adapter model listing", () => {
 
     expect(fetchSpy).toHaveBeenCalledTimes(2);
     expect(initial.some((model) => model.id === "gpt-5")).toBe(true);
-    expect(refreshed.some((model) => model.id === "gpt-5.5")).toBe(true);
+    expect(refreshed.some((model) => model.id === "gpt-5.6-terra")).toBe(true);
+    expect(refreshed.some((model) => model.id === "gpt-5.6-luna")).toBe(true);
   });
 
   it("falls back to static codex models when OpenAI model discovery fails", async () => {
diff --git a/ui/src/components/agent-config-primitives.tsx b/ui/src/components/agent-config-primitives.tsx
index 0ffabc35b9..eea519c93d 100644
--- a/ui/src/components/agent-config-primitives.tsx
+++ b/ui/src/components/agent-config-primitives.tsx
@@ -34,7 +34,7 @@ export const help: Record<string, string> = {
   dangerouslySkipPermissions: "Run unattended by auto-approving adapter permission prompts when supported.",
   dangerouslyBypassSandbox: "Run Codex without sandbox restrictions. Required for filesystem/network access.",
   search: "Enable Codex web search capability during runs.",
-  fastMode: "Enable Codex Fast mode. This burns credits/tokens much faster and is supported on GPT-5.4 and manual Codex model IDs.",
+  fastMode: "Enable Codex Fast mode. This burns credits/tokens much faster and is supported on GPT-5.6, GPT-5.5, GPT-5.4, and manual Codex model IDs.",
   workspaceStrategy: "How Paperclip should realize an execution workspace for this agent. Keep project_primary for normal cwd execution, or use git_worktree for issue-scoped isolated checkouts.",
   workspaceBaseRef: "Base git ref used when creating a worktree branch. Leave blank to use the resolved workspace ref or HEAD.",
   workspaceBranchTemplate: "Template for naming derived branches. Supports {{issue.identifier}}, {{issue.title}}, {{agent.name}}, {{project.id}}, {{workspace.repoRef}}, and {{slug}}.",