expect(assistant.reasoning_content).toBe("Need to answer politely.");

});

it("strips empty-string reasoning_content from OpenRouter assistant replay", () => {

// DeepSeek V4 via OpenRouter injects reasoning_content: "" on tool-call

// assistant messages. An empty string is technically a "string" but the

// Chat Completions schema does not accept it, and OpenRouter rejects the

// replayed message with HTTP 500.

const params = buildOpenAICompletionsParams(

openRouterModel,

{

systemPrompt: "system",

messages: [

{ role: "user", content: "read config" },

{

role: "assistant",

provider: "openrouter",

api: "openai-completions",

model: "deepseek/deepseek-v4-pro",

stopReason: "toolUse",

timestamp: 0,

content: [

{

type: "thinking",

thinking: "",

thinkingSignature: "reasoning_content",

},

{

type: "toolCall",

id: "call_1",

name: "read_file",

arguments: { path: "config.json" },

},

],

},

{

role: "toolResult",

toolCallId: "call_1",

toolName: "read_file",

content: [{ type: "text", text: "{ }" }],

isError: false,

timestamp: 1,

},

{ role: "user", content: "continue" },

],

tools: [],

} as never,

undefined,

) as { messages: unknown };

const msgs = params.messages as Record<string, unknown>[];

const assistantMsgs = msgs.filter((m) => m.role === "assistant");

for (const msg of assistantMsgs) {

expect(msg).not.toHaveProperty("reasoning_content");

}

});

it("preserves OpenRouter array reasoning_details from tool-call signatures", () => {

const reasoningDetail = { type: "reasoning.encrypted", id: "rs_1", data: "ciphertext" };

const params = buildOpenAICompletionsParams(