environmentSelection?: CodexTurnEnvironmentParams[];

pluginThreadConfig?: CodexPluginThreadConfigProvider;

contextEngineProjection?: CodexContextEngineThreadBootstrapProjection;

signal?: AbortSignal;

}): Promise<CodexAppServerThreadLifecycleBinding> {

// Thread lifecycle spans are useful when profiling startup churn, but normal

// turns should not pay Date.now/span-array overhead while resuming threads.

let preserveExistingBinding = false;

let rotatedContextEngineBinding = false;

let prebuiltPluginThreadConfig: CodexPluginThreadConfig | undefined;

const throwIfAborted = () => {

if (!params.signal?.aborted) {

return;

}

const reason = params.signal.reason;

if (reason instanceof Error) {

throw reason;

}

const error = new Error(

typeof reason === "string" && reason.length > 0

? reason

: "codex app-server thread lifecycle aborted",

);

error.name = "AbortError";

throw error;

};

if (binding?.threadId && params.nativeCodeModeEnabled === false) {

embeddedAgentLog.debug(

"codex app-server native tool surface disabled for turn; starting transient thread",

);

const response = assertCodexThreadResumeResponse(

await lifecycleTiming.measure("thread_resume_request", () =>

params.client.request("thread/resume", resumeParams),

params.client.request("thread/resume", resumeParams, { signal: params.signal }),

),

);

throwIfAborted();

const boundAuthProfileId = authProfileId;

const fallbackModelProvider = resolveCodexAppServerModelProvider({

provider: params.params.provider,

);

const threadStartResponse = await lifecycleTiming.measure("thread_start_request", async () => {

try {

return await params.client.request("thread/start", startParams);

return await params.client.request("thread/start", startParams, { signal: params.signal });

} catch (error) {

if (error instanceof CodexAppServerRpcError) {

throw new CodexThreadStartRequestError(error);

}

});

const response = assertCodexThreadStartResponse(threadStartResponse);

throwIfAborted();

const modelProvider = resolveCodexAppServerModelProvider({

provider: params.params.provider,

authProfileId: params.params.authProfileId,