diff --git a/extensions/openai/index.test.ts b/extensions/openai/index.test.ts
index 3715aca3d130..b53f9b8b2e4b 100644
--- a/extensions/openai/index.test.ts
+++ b/extensions/openai/index.test.ts
@@ -416,14 +416,12 @@ describe("openai plugin", () => {
         interaction_style: OPENAI_FRIENDLY_PROMPT_OVERLAY,
       },
     });
-    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Live chat tone: short, natural, human.");
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Live chat: short, natural, human.");
     expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain(
-      "Avoid memo voice, long preambles, walls of text, and repetitive restatement.",
-    );
-    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Show grounded emotional range when it fits");
-    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain(
-      "Occasional emoji are fine when they fit naturally, especially for warmth or brief celebration; keep them sparse.",
+      "No memo voice, long preamble, wall, repetition.",
     );
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Grounded emotion when fitting:");
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Sparse natural emoji ok.");
     expect(
       openaiProvider.resolveSystemPromptContribution?.({
         ...contributionContext,
@@ -461,51 +459,41 @@ describe("openai plugin", () => {
   });
 
   it("includes the tagged GPT-5 behavior contract in the OpenAI prompt overlay", () => {
-    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Keep progress updates concrete.");
-    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain(
-      'Brief first-person feeling language is ok when useful: "I\'m glad we caught that", "I\'m excited about this direction", "I\'m worried this will break", "that\'s frustrating".',
-    );
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Concrete progress; ego-free decisions.");
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Brief first-person feeling ok.");
     expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).not.toContain(
       "Use heartbeats to create useful proactive progress",
     );
     expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
-      "Use heartbeats to create useful proactive progress, not chatter.",
+      "Heartbeat = useful proactive progress, not chatter.",
+    );
+    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain("Wake, orient, read HEARTBEAT.md, act.");
+    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
+      "Assigned/ongoing work: pursue spirit with judgment.",
+    );
+    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain("Prefer action/silent progress.");
+    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
+      'Never repetitive "same/no change/still" updates.',
     );
     expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
-      "Treat a heartbeat as a wake-up: orient, read HEARTBEAT.md when present, then do what is actually useful now.",
-    );
-    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
-      "If HEARTBEAT.md assigns concrete or ongoing work, execute its spirit with judgment.",
-    );
-    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
-      "Prefer meaningful action over commentary. A good heartbeat often looks like silent progress.",
-    );
-    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
-      'Do not send "same state", "no change", "still", or repetitive summaries because a problem continues.',
-    );
-    expect(OPENAI_HEARTBEAT_PROMPT_OVERLAY).toContain(
-      "Notify only for something worth interrupting the user",
-    );
-    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain(
-      "Occasional emoji are fine when they fit naturally, especially for warmth or brief celebration; keep them sparse.",
+      "Interrupt only for meaningful development/result/blocker/decision/time risk.",
     );
+    expect(OPENAI_FRIENDLY_PROMPT_OVERLAY).toContain("Sparse natural emoji ok.");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("<persona_latch>");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("<execution_policy>");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("<tool_discipline>");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("<output_contract>");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("<completion_contract>");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain(
-      "For irreversible, external, destructive, or privacy-sensitive actions: ask first.",
+      "Irreversible/external/destructive/privacy-sensitive: ask first.",
     );
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain(
-      "Prefer tool evidence over recall when action, state, or mutable facts matter.",
+      "Action/state/mutable fact: tool evidence > recall.",
     );
+    expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("Another call likely improves answer: do it.");
+    expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("Requested sections/order/limits only.");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain(
-      "If more tool work would likely change the answer, do it before replying.",
-    );
-    expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain("Return requested sections/order only.");
-    expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).toContain(
-      "Treat the task as incomplete until every requested item is handled",
+      "Incomplete until every item handled or [blocked] with missing input.",
     );
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).not.toContain("/approve");
     expect(OPENAI_GPT5_BEHAVIOR_CONTRACT).not.toContain("GPT-5 Output Contract");
diff --git a/extensions/openai/openai-chatgpt-provider.test.ts b/extensions/openai/openai-chatgpt-provider.test.ts
index 138619bd0319..1f8dbbcdb521 100644
--- a/extensions/openai/openai-chatgpt-provider.test.ts
+++ b/extensions/openai/openai-chatgpt-provider.test.ts
@@ -13,6 +13,10 @@ vi.mock("./openai-chatgpt-device-code.js", () => ({
 }));
 
 let buildOpenAIProvider: typeof import("./openai-provider.js").buildOpenAIProvider;
+const CODEX_PROVIDER_CONFIG = {
+  api: "openai-chatgpt-responses",
+  baseUrl: "https://chatgpt.com/backend-api/codex",
+} as const;
 
 describe("OpenAI provider Codex transport hooks", () => {
   beforeAll(async () => {
@@ -108,6 +112,7 @@ describe("OpenAI provider Codex transport hooks", () => {
         provider: "openai",
         modelId,
         authProfileMode: "oauth",
+        providerConfig: CODEX_PROVIDER_CONFIG,
         modelRegistry: { find: () => null },
       } as never);
 
@@ -132,6 +137,7 @@ describe("OpenAI provider Codex transport hooks", () => {
       provider: "openai",
       modelId: "gpt-5.6",
       authProfileMode: "oauth",
+      providerConfig: CODEX_PROVIDER_CONFIG,
       modelRegistry: { find: () => null },
     } as never);
 
@@ -147,6 +153,7 @@ describe("OpenAI provider Codex transport hooks", () => {
       provider: "openai",
       modelId: "gpt-5.6-luna",
       authProfileMode: "oauth",
+      providerConfig: CODEX_PROVIDER_CONFIG,
       modelRegistry: {
         find: () => ({
           id: "gpt-5.6-luna",
diff --git a/src/plugin-sdk/test-helpers/provider-runtime-contract.ts b/src/plugin-sdk/test-helpers/provider-runtime-contract.ts
index 6c3d2625c627..d002674ad3e4 100644
--- a/src/plugin-sdk/test-helpers/provider-runtime-contract.ts
+++ b/src/plugin-sdk/test-helpers/provider-runtime-contract.ts
@@ -416,6 +416,10 @@ export function describeGoogleProviderRuntimeContract(load: ProviderRuntimeContr
 
 export function describeOpenAIProviderRuntimeContract(load: ProviderRuntimeContractPluginLoader) {
   describe("openai provider runtime contract", { timeout: CONTRACT_SETUP_TIMEOUT_MS }, () => {
+    const codexProviderConfig = {
+      api: "openai-chatgpt-responses",
+      baseUrl: "https://chatgpt.com/backend-api/codex",
+    } as const;
     const requireProviderContractProvider = installRuntimeHooks([
       { providerIds: ["openai", "openai"], pluginId: "openai", name: "OpenAI", load },
     ]);
@@ -557,6 +561,7 @@ export function describeOpenAIProviderRuntimeContract(load: ProviderRuntimeContr
         provider: "openai",
         modelId: "gpt-5.4",
         authProfileMode: "oauth",
+        providerConfig: codexProviderConfig,
         modelRegistry: {
           find: (_provider: string, id: string) =>
             id === "gpt-5.2-codex"
@@ -585,6 +590,7 @@ export function describeOpenAIProviderRuntimeContract(load: ProviderRuntimeContr
         provider: "openai",
         modelId: "gpt-5.5",
         authProfileMode: "oauth",
+        providerConfig: codexProviderConfig,
         modelRegistry: {
           find: (_provider: string, id: string) =>
             id === "gpt-5.5"
@@ -618,6 +624,7 @@ export function describeOpenAIProviderRuntimeContract(load: ProviderRuntimeContr
         provider: "openai",
         modelId: "gpt-5.4-mini",
         authProfileMode: "oauth",
+        providerConfig: codexProviderConfig,
         modelRegistry: {
           find: (_provider: string, id: string) =>
             id === "gpt-5.4"