msg.model !== model.id && msg.provider === model.provider && msg.api === model.api;

for (const block of msg.content) {

if (block.type === "thinking") {

if (shouldReplayReasoningItems && block.thinkingSignature) {

if (

shouldReplayReasoningItems &&

block.thinkingSignature &&

block.thinkingSignature.startsWith("{")

) {

// openai-completions plain-text reasoning paths persist a

// provenance tag (e.g. "reasoning", "reasoning_details", "content")

// as thinkingSignature rather than a JSON-encoded reasoning item.

// Replaying those values would corrupt the next request payload

// (OpenRouter returns HTTP 500), so skip non-JSON signatures.

const reasoningItem = JSON.parse(

block.thinkingSignature,

) as ReplayableResponseReasoningItem;

);

}

function shouldPreserveOpenRouterReasoningReplay(model: OpenAIModeModel): boolean {

if (model.provider !== "openrouter") {

return true;

}

const normalizedModelId = model.id.trim().toLowerCase();

return !(normalizedModelId.startsWith("anthropic/") || normalizedModelId.startsWith("x-ai/"));

}

// OpenAI Chat Completions assistant-message input does not define reasoning

// replay fields, while OpenRouter and DeepSeek-style providers document

// compatible pass-back contracts. Keep valid provider-owned replay fields, but

let messages = convertMessages(model as never, completionsContext, compat as never);

injectToolCallThoughtSignatures(messages as unknown[], context, model);

sanitizeCompletionsReasoningReplayFields(messages, {

preserveOpenRouterReasoning: compat.thinkingFormat === "openrouter",

preserveOpenRouterReasoning:

compat.thinkingFormat === "openrouter" && shouldPreserveOpenRouterReasoningReplay(model),

preserveReasoningContent: shouldPreserveReasoningContentReplay(model, compat),

});

if (compat.strictMessageKeys) {