diff --git a/packages/ai/scripts/generate-models.ts b/packages/ai/scripts/generate-models.ts
index 4fd84d86..5fad8aaf 100644
--- a/packages/ai/scripts/generate-models.ts
+++ b/packages/ai/scripts/generate-models.ts
@@ -1370,11 +1370,12 @@ async function loadModelsDevData(): Promise<Model<any>[]> {
 				const npm = m.provider?.npm;
 				let api: Api;
 				let baseUrl: string;
-				let compat: OpenAICompletionsCompat | undefined;
+				let compat: OpenAICompletionsCompat | OpenAIResponsesCompat | undefined;
 
 				if (npm === "@ai-sdk/openai") {
 					api = "openai-responses";
 					baseUrl = `${variant.basePath}/v1`;
+					compat = { sessionAffinityFormat: "openai-nosession" };
 				} else if (npm === "@ai-sdk/anthropic") {
 					api = "anthropic-messages";
 					// Anthropic SDK appends /v1/messages to baseURL
diff --git a/packages/ai/src/providers/opencode.models.ts b/packages/ai/src/providers/opencode.models.ts
index ad18727a..cd2cfd34 100644
--- a/packages/ai/src/providers/opencode.models.ts
+++ b/packages/ai/src/providers/opencode.models.ts
@@ -392,6 +392,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -410,6 +411,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -428,6 +430,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -446,6 +449,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -464,6 +468,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -482,6 +487,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -500,6 +506,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null},
 		input: ["text", "image"],
@@ -518,6 +525,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -536,6 +544,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -554,6 +563,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -572,6 +582,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -590,6 +601,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -608,6 +620,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -626,6 +639,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -644,6 +658,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh"},
 		input: ["text", "image"],
@@ -662,6 +677,7 @@ export const OPENCODE_MODELS = {
 		api: "openai-responses",
 		provider: "opencode",
 		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
 		reasoning: true,
 		thinkingLevelMap: {"off":null,"xhigh":"xhigh","minimal":null,"low":null},
 		input: ["text", "image"],
@@ -674,6 +690,63 @@ export const OPENCODE_MODELS = {
 		contextWindow: 1050000,
 		maxTokens: 128000,
 	} satisfies Model<"openai-responses">,
+	"gpt-5.6-luna": {
+		id: "gpt-5.6-luna",
+		name: "GPT-5.6 Luna",
+		api: "openai-responses",
+		provider: "opencode",
+		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
+		reasoning: true,
+		thinkingLevelMap: {"off":null,"xhigh":"xhigh","max":"max"},
+		input: ["text", "image"],
+		cost: {
+			input: 1,
+			output: 6,
+			cacheRead: 0.1,
+			cacheWrite: 1.25,
+		},
+		contextWindow: 1050000,
+		maxTokens: 128000,
+	} satisfies Model<"openai-responses">,
+	"gpt-5.6-sol": {
+		id: "gpt-5.6-sol",
+		name: "GPT-5.6 Sol",
+		api: "openai-responses",
+		provider: "opencode",
+		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
+		reasoning: true,
+		thinkingLevelMap: {"off":null,"xhigh":"xhigh","max":"max"},
+		input: ["text", "image"],
+		cost: {
+			input: 5,
+			output: 30,
+			cacheRead: 0.5,
+			cacheWrite: 6.25,
+		},
+		contextWindow: 1050000,
+		maxTokens: 128000,
+	} satisfies Model<"openai-responses">,
+	"gpt-5.6-terra": {
+		id: "gpt-5.6-terra",
+		name: "GPT-5.6 Terra",
+		api: "openai-responses",
+		provider: "opencode",
+		baseUrl: "https://opencode.ai/zen/v1",
+		compat: {"sessionAffinityFormat":"openai-nosession"},
+		reasoning: true,
+		thinkingLevelMap: {"off":null,"xhigh":"xhigh","max":"max"},
+		input: ["text", "image"],
+		cost: {
+			input: 2.5,
+			output: 15,
+			cacheRead: 0.25,
+			cacheWrite: 3.125,
+		},
+		contextWindow: 1050000,
+		maxTokens: 128000,
+	} satisfies Model<"openai-responses">,
 	"grok-4.5": {
 		id: "grok-4.5",
 		name: "Grok 4.5",
@@ -726,7 +799,7 @@ export const OPENCODE_MODELS = {
 			cacheRead: 0,
 			cacheWrite: 0,
 		},
-		contextWindow: 256000,
+		contextWindow: 190000,
 		maxTokens: 64000,
 	} satisfies Model<"openai-completions">,
 	"kimi-k2.5": {
diff --git a/packages/ai/test/openai-responses-copilot-provider.test.ts b/packages/ai/test/openai-responses-compat.test.ts
similarity index 94%
rename from packages/ai/test/openai-responses-copilot-provider.test.ts
rename to packages/ai/test/openai-responses-compat.test.ts
index 8eeedea7..cabab825 100644
--- a/packages/ai/test/openai-responses-copilot-provider.test.ts
+++ b/packages/ai/test/openai-responses-compat.test.ts
@@ -360,6 +360,26 @@ describe("openai-responses provider defaults", () => {
 		expect(capturedPayload?.prompt_cache_key).toBe("session-proxy");
 	});
 
+	it("uses OpenAI no-session format for OpenCode Responses models", async () => {
+		const model = getModel("opencode", "gpt-5.4");
+		let capturedPayload: CapturedResponsesPayload | undefined;
+		const captured = await captureOpenAIResponseHeaders(
+			{
+				sessionId: "session-opencode",
+				onPayload: (payload) => {
+					capturedPayload = payload as CapturedResponsesPayload;
+				},
+			},
+			model,
+		);
+
+		expect(model.compat?.sessionAffinityFormat).toBe("openai-nosession");
+		expect(captured.sessionId).toBeNull();
+		expect(captured.clientRequestId).toBe("session-opencode");
+		expect(captured.xSessionId).toBeNull();
+		expect(capturedPayload?.prompt_cache_key).toBe("session-opencode");
+	});
+
 	it("can omit OpenAI session_id header while preserving other affinity data", async () => {
 		const proxyModel: Model<"openai-responses"> = {
 			...getModel("openai", "gpt-5.4"),