{

content: {

parts: [

{ thought: true, text: "draft", thoughtSignature: "sig_1" },

{ thought: true, text: "draft", thoughtSignature: "c2lnXzE=" },

{ text: "answer" },

{

thoughtSignature: "call_sig_1",

thoughtSignature: "Y2FsbF9zaWdfMQ==",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

expect(result.content[0]).toEqual({

type: "thinking",

thinking: "draft",

thinkingSignature: "sig_1",

thinkingSignature: "c2lnXzE=",

});

expect(result.content[1]?.type).toBe("text");

expect(result.content[1]).toHaveProperty("text", "answer");

expect(result.content[2]?.type).toBe("toolCall");

expect(result.content[2]).toHaveProperty("name", "lookup");

expect(result.content[2]).toHaveProperty("arguments", { q: "hello" });

expect(result.content[2]).toHaveProperty("thoughtSignature", "call_sig_1");

expect(result.content[2]).toHaveProperty("thoughtSignature", "Y2FsbF9zaWdfMQ==");

});

it("merges tool-call thought signatures from sibling SSE parts", async () => {

{

functionCall: { id: "call_1", name: "lookup", args: { q: "hello" } },

},

{ thoughtSignature: "call_sig_merged_1" },

{ thoughtSignature: "Y2FsbF9zaWdfbWVyZ2VkXzE=" },

],

},

finishReason: "STOP",

id: "call_1",

name: "lookup",

arguments: { q: "hello" },

thoughtSignature: "call_sig_merged_1",

thoughtSignature: "Y2FsbF9zaWdfbWVyZ2VkXzE=",

},

]);

});

{

functionCall: { id: "call_1", name: "lookup", args: { q: "hello" } },

},

{ thought: true, thoughtSignature: "thought_sig_after_call" },

{ thought: true, thoughtSignature: "dGhvdWdodF9zaWdfYWZ0ZXJfY2FsbA==" },

{ thought: true, text: "draft" },

{ text: "answer" },

],

expect(result.content[1]).toEqual({

type: "thinking",

thinking: "draft",

thinkingSignature: "thought_sig_after_call",

thinkingSignature: "dGhvdWdodF9zaWdfYWZ0ZXJfY2FsbA==",

});

expect(result.content[2]).toEqual({ type: "text", text: "answer" });

});

id: "call_1",

name: "lookup",

arguments: { q: "hello" },

thoughtSignature: "call_sig_1",

thoughtSignature: "Y2FsbF9zaWdfMQ==",

},

],

},

role: "model",

parts: [

{

thoughtSignature: "call_sig_1",

thoughtSignature: "Y2FsbF9zaWdfMQ==",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

const params = buildGoogleGenerativeAiParams(model, {

messages: [

googleToolCallAssistantTurn({ thoughtSignature: "call_sig_replay_1" }),

googleToolCallAssistantTurn({ thoughtSignature: "Y2FsbF9zaWdfcmVwbGF5XzE=" }),

toolResultTurn(),

googleToolCallAssistantTurn({ timestamp: 2 }),

],

role: "model",

parts: [

{

thoughtSignature: "call_sig_replay_1",

thoughtSignature: "Y2FsbF9zaWdfcmVwbGF5XzE=",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

const params = buildGoogleGenerativeAiParams(model, {

messages: [

googleToolCallAssistantTurn({ thoughtSignature: "call_sig_alias_1" }),

googleToolCallAssistantTurn({ thoughtSignature: "Y2FsbF9zaWdfYWxpYXNfMQ==" }),

toolResultTurn(),

googleToolCallAssistantTurn({ timestamp: 2 }),

],

role: "model",

parts: [

{

thoughtSignature: "call_sig_alias_1",

thoughtSignature: "Y2FsbF9zaWdfYWxpYXNfMQ==",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

{

type: "thinking",

thinking: "plan",

thinkingSignature: "think_sig_alias_1",

thinkingSignature: "dGhpbmtfc2lnX2FsaWFzXzE=",

},

{

type: "text",

text: "answer",

textSignature: "text_sig_alias_1",

textSignature: "dGV4dF9zaWdfYWxpYXNfMQ==",

},

],

},

{

thought: true,

text: "plan",

thoughtSignature: "think_sig_alias_1",

thoughtSignature: "dGhpbmtfc2lnX2FsaWFzXzE=",

},

{

text: "answer",

thoughtSignature: "text_sig_alias_1",

thoughtSignature: "dGV4dF9zaWdfYWxpYXNfMQ==",

},

],

});

const params = buildGoogleGenerativeAiParams(model, {

messages: [

googleToolCallAssistantTurn({ thoughtSignature: "opaque.sig-url_safe~1" }),

googleToolCallAssistantTurn({ thoughtSignature: "b3BhcXVlLnNpZy11cmxfc2FmZX4x" }),

toolResultTurn(),

googleToolCallAssistantTurn({ timestamp: 2 }),

],

role: "model",

parts: [

{

thoughtSignature: "opaque.sig-url_safe~1",

thoughtSignature: "b3BhcXVlLnNpZy11cmxfc2FmZX4x",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

const params = buildGoogleGenerativeAiParams(model, {

messages: [

googleToolCallAssistantTurn({ thoughtSignature: "call_sig_first_1" }),

googleToolCallAssistantTurn({ thoughtSignature: "Y2FsbF9zaWdfZmlyc3RfMQ==" }),

toolResultTurn(),

googleToolCallAssistantTurn({

timestamp: 2,

thoughtSignature: "call_sig_second_1",

thoughtSignature: "Y2FsbF9zaWdfc2Vjb25kXzE=",

}),

],

} as never);

expect(modelTurns[0]).toMatchObject({

parts: [

{

thoughtSignature: "call_sig_first_1",

thoughtSignature: "Y2FsbF9zaWdfZmlyc3RfMQ==",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

});

expect(modelTurns[1]).toMatchObject({

parts: [

{

thoughtSignature: "call_sig_second_1",

thoughtSignature: "Y2FsbF9zaWdfc2Vjb25kXzE=",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

toolResultTurn(),

googleToolCallAssistantTurn({

timestamp: 2,

thoughtSignature: "call_sig_future_1",

thoughtSignature: "Y2FsbF9zaWdfZnV0dXJlXzE=",

}),

],

} as never);

expect(modelTurns[1]).toMatchObject({

parts: [

{

thoughtSignature: "call_sig_future_1",

thoughtSignature: "Y2FsbF9zaWdfZnV0dXJlXzE=",

functionCall: { name: "lookup", args: { q: "hello" } },

},

],

const params = buildGoogleGenerativeAiParams(model, {

messages: [

googleToolCallAssistantTurn({ thoughtSignature: "call_sig_replay_1" }),

googleToolCallAssistantTurn({ thoughtSignature: "Y2FsbF9zaWdfcmVwbGF5XzE=" }),

toolResultTurn(),

googleToolCallAssistantTurn({ timestamp: 2, args: { q: "hello-again" } }),

],

model: "claude-sonnet-4",

id: "call_foreign",

// Plausible-looking base64 from a non-Gemini provider.

thoughtSignature: "msg_01XFDUDYJgAACcnSM2TTgQsA",

thoughtSignature: "bXNnXzAxWEZEVURZSmdBQUNjblNNMlRUZ1FzQQ==",

}),

toolResultTurn("call_foreign"),

{

},

],

});

expect(firstModelTurn.parts[0].thoughtSignature).not.toBe("msg_01XFDUDYJgAACcnSM2TTgQsA");

expect(firstModelTurn.parts[0].thoughtSignature).not.toBe(

"bXNnXzAxWEZEVURZSmdBQUNjblNNMlRUZ1FzQQ==",

);

});

it("does not replay prior Gemini thought signatures onto a later foreign route", () => {

const params = buildGoogleGenerativeAiParams(model, {

messages: [

googleToolCallAssistantTurn({ thoughtSignature: "call_sig_google_1" }),

googleToolCallAssistantTurn({ thoughtSignature: "Y2FsbF9zaWdfZ29vZ2xlXzE=" }),

toolResultTurn(),

googleToolCallAssistantTurn({

provider: "anthropic",

},

],

});

expect(modelTurns[1]?.parts[0].thoughtSignature).not.toBe("call_sig_google_1");

expect(modelTurns[1]?.parts[0].thoughtSignature).not.toBe("Y2FsbF9zaWdfZ29vZ2xlXzE=");

});

it("replaces invalid Gemini tool-call sentinel signatures with the skip fallback", () => {

id: "call_math",

name: "math_eval",

arguments: { expression: "17*23" },

thoughtSignature: "real_sig_1",

thoughtSignature: "cmVhbF9zaWdfMQ==",

},

{

type: "toolCall",

const parts = (params.contents[0] as { parts: Array<Record<string, unknown>> }).parts;

expect(parts).toHaveLength(3);

expect(parts[0]).toMatchObject({

thoughtSignature: "real_sig_1",

thoughtSignature: "cmVhbF9zaWdfMQ==",

functionCall: { name: "math_eval", args: { expression: "17*23" } },

});

expect(parts[1]).toMatchObject({

id: "call_1",

name: "lookup",

arguments: { q: "hello" },

thoughtSignature: "foreign_sig",

thoughtSignature: "Zm9yZWlnbl9zaWc=",

},

],

},

role: "model",

parts: [{ functionCall: { name: "lookup", args: { q: "hello" } } }],

});

expect(JSON.stringify(params.contents)).not.toContain("foreign_sig");

expect(JSON.stringify(params.contents)).not.toContain("Zm9yZWlnbl9zaWc=");

expect(JSON.stringify(params.contents)).not.toContain("skip_thought_signature_validator");

});

{

content: {

parts: [

{ thought: true, text: "draft", thoughtSignature: "sig_1" },

{ thoughtSignature: "sig_2" },

{ thought: true, text: "draft", thoughtSignature: "c2lnXzE=" },

{ thoughtSignature: "c2lnXzI=" },

{ text: "answer" },

],

},

const result = await stream.result();

expect(result.content).toEqual([

{ type: "thinking", thinking: "draft", thinkingSignature: "sig_2" },

{ type: "thinking", thinking: "draft", thinkingSignature: "c2lnXzI=" },

{ type: "text", text: "answer" },

]);

expect(events.map((event) => event.type)).toEqual([

{

content: {

parts: [

{ thoughtSignature: "sig_1" },

{ thoughtSignature: "c2lnXzE=" },

{ thought: true, text: "draft" },

{ text: "answer" },

],

const result = await stream.result();

expect(result.content).toEqual([

{ type: "thinking", thinking: "draft", thinkingSignature: "sig_1" },

{ type: "thinking", thinking: "draft", thinkingSignature: "c2lnXzE=" },

{ type: "text", text: "answer" },

]);

});