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feat: add request timing markers #105

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Merged
Nomadcxx merged 1 commit into from
Jun 18, 2026
Merged

feat: add request timing markers #105

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103 changes: 67 additions & 36 deletions src/plugin.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1150,7 +1150,10 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
}

log.debug("Proxy request (bun)", { method: req.method, path: url.pathname });
const reqPerf = new RequestPerf(`bun-${Date.now()}`);
const body: any = await req.json().catch(() => ({}));
reqPerf.mark("body-read");
reqPerf.mark("body-parsed");
const messages: Array<any> = Array.isArray(body?.messages) ? body.messages : [];
const stream = body?.stream === true;
const tools = Array.isArray(body?.tools) ? body.tools : [];
Expand Down Expand Up @@ -1179,6 +1182,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const authHeader = req.headers.get("authorization");
const sdkApiKey = resolveRequestSdkApiKey(authHeader);
const backend = resolveBackendForRequest(sdkApiKey);
reqPerf.mark("backend-resolved");
const {
prompt,
resumeChatId,
Expand All @@ -1196,6 +1200,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
model,
workspaceDirectory,
});
reqPerf.mark("prompt-built");
const sessionResumeKeyHash = sessionResumeKey ? sanitizeSessionKey(sessionResumeKey) : undefined;
const resumeChatIdHash = resumeChatId ? sanitizeSessionKey(resumeChatId) : undefined;
const msgSummaryBun = messages.map((m: any, i: number) => {
Expand All @@ -1221,6 +1226,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
);
}

reqPerf.mark("child-create-start");
const child = createBunChildForBackend({
backend,
sdkApiKey,
Expand All @@ -1229,6 +1235,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
workspaceDirectory,
resumeChatId,
});
reqPerf.mark("child-created");

if (!stream) {
const [stdoutText, stderrText] = await Promise.all([
Expand Down Expand Up @@ -1341,18 +1348,27 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const encoder = new TextEncoder();
const id = `cursor-acp-${Date.now()}`;
const created = Math.floor(Date.now() / 1000);
const perf = new RequestPerf(id);
const perf = reqPerf;
const toolMapper = new ToolMapper();
const toolSessionId = id;
const passThroughTracker = new PassThroughTracker();

perf.mark("spawn");
perf.mark("child-dispatched");
const sse = new ReadableStream({
async start(controller) {
let streamTerminated = false;
let firstTokenReceived = false;
let firstStdoutByteReceived = false;
let firstSseWritten = false;
let sawSuccessfulStreamOutput = false;
let usage: OpenAiUsage | undefined;
const enqueueSse = (payload: string) => {
if (!firstSseWritten) {
perf.mark("first-sse-write");
firstSseWritten = true;
}
controller.enqueue(encoder.encode(payload));
};
try {
const reader = (child.stdout as ReadableStream<Uint8Array>).getReader();
const converter = new StreamToSseConverter(model, { id, created });
Expand All @@ -1368,9 +1384,9 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
boundary.createStreamToolCallChunks({ id, created, model }, toolCall),
);
for (const chunk of streamChunks) {
controller.enqueue(encoder.encode(`data: ${JSON.stringify(chunk)}\n\n`));
enqueueSse(`data: ${JSON.stringify(chunk)}\n\n`);
}
controller.enqueue(encoder.encode(formatSseDone()));
enqueueSse(formatSseDone());
streamTerminated = true;
try {
child.kill();
Expand All @@ -1383,8 +1399,8 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
return;
}
const errChunk = createChatCompletionChunk(id, created, model, message, true);
controller.enqueue(encoder.encode(`data: ${JSON.stringify(errChunk)}\n\n`));
controller.enqueue(encoder.encode(formatSseDone()));
enqueueSse(`data: ${JSON.stringify(errChunk)}\n\n`);
enqueueSse(formatSseDone());
streamTerminated = true;
try {
child.kill();
Expand All @@ -1398,6 +1414,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const { value, done } = await reader.read();
if (done) break;
if (!value || value.length === 0) continue;
if (!firstStdoutByteReceived) { perf.mark("first-stdout-byte"); firstStdoutByteReceived = true; }
if (!firstTokenReceived) { perf.mark("first-token"); firstTokenReceived = true; }

for (const line of lineBuffer.push(value)) {
Expand Down Expand Up @@ -1443,10 +1460,10 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
responseMeta: { id, created, model },
passThroughTracker,
onToolUpdate: (update) => {
controller.enqueue(encoder.encode(formatToolUpdateEvent(update)));
enqueueSse(formatToolUpdateEvent(update));
},
onToolResult: (toolResult) => {
controller.enqueue(encoder.encode(`data: ${JSON.stringify(toolResult)}\n\n`));
enqueueSse(`data: ${JSON.stringify(toolResult)}\n\n`);
},
onInterceptedToolCall: (toolCall) => {
emitToolCallAndTerminate(toolCall);
Expand All @@ -1460,7 +1477,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
emitTerminalAssistantErrorAndTerminate(result.terminate.message);
} else {
// Silent termination: just end the stream without an error message
controller.enqueue(encoder.encode(formatSseDone()));
enqueueSse(formatSseDone());
streamTerminated = true;
try { child.kill(); } catch { /* ignore */ }
}
Expand All @@ -1479,7 +1496,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
sawSuccessfulStreamOutput = true;
}
for (const sse of sseChunks) {
controller.enqueue(encoder.encode(sse));
enqueueSse(sse);
}
}
}
Expand Down Expand Up @@ -1527,10 +1544,10 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
responseMeta: { id, created, model },
passThroughTracker,
onToolUpdate: (update) => {
controller.enqueue(encoder.encode(formatToolUpdateEvent(update)));
enqueueSse(formatToolUpdateEvent(update));
},
onToolResult: (toolResult) => {
controller.enqueue(encoder.encode(`data: ${JSON.stringify(toolResult)}\n\n`));
enqueueSse(`data: ${JSON.stringify(toolResult)}\n\n`);
},
onInterceptedToolCall: (toolCall) => {
emitToolCallAndTerminate(toolCall);
Expand All @@ -1543,7 +1560,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
if (!result.terminate.silent) {
emitTerminalAssistantErrorAndTerminate(result.terminate.message);
} else {
controller.enqueue(encoder.encode(formatSseDone()));
enqueueSse(formatSseDone());
streamTerminated = true;
try { child.kill(); } catch { /* ignore */ }
}
Expand All @@ -1561,7 +1578,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
sawSuccessfulStreamOutput = true;
}
for (const sse of sseChunks) {
controller.enqueue(encoder.encode(sse));
enqueueSse(sse);
}
}
if (streamTerminated) {
Expand Down Expand Up @@ -1594,8 +1611,8 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
failureTextHash: hashForLog(parsed.message),
});
const errChunk = createChatCompletionChunk(id, created, model, msg, true);
controller.enqueue(encoder.encode(`data: ${JSON.stringify(errChunk)}\n\n`));
controller.enqueue(encoder.encode(formatSseDone()));
enqueueSse(`data: ${JSON.stringify(errChunk)}\n\n`);
enqueueSse(formatSseDone());
return;
}
}
Expand All @@ -1622,12 +1639,12 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
}

const doneChunk = createChatCompletionChunk(id, created, model, "", true);
controller.enqueue(encoder.encode(`data: ${JSON.stringify(doneChunk)}\n\n`));
enqueueSse(`data: ${JSON.stringify(doneChunk)}\n\n`);
if (usage) {
const usageChunk = createChatCompletionUsageChunk(id, created, model, usage);
controller.enqueue(encoder.encode(`data: ${JSON.stringify(usageChunk)}\n\n`));
enqueueSse(`data: ${JSON.stringify(usageChunk)}\n\n`);
}
controller.enqueue(encoder.encode(formatSseDone()));
enqueueSse(formatSseDone());
} finally {
perf.mark("request:done");
perf.summarize();
Expand Down Expand Up @@ -1712,13 +1729,16 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
}

log.debug("Proxy request (node)", { method: req.method, path: url.pathname });
const reqPerf = new RequestPerf(`node-${Date.now()}`);
const bodyChunks: Buffer[] = [];
for await (const chunk of req) {
bodyChunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
}
reqPerf.mark("body-read");
const body = Buffer.concat(bodyChunks).toString("utf8");

const bodyData: any = JSON.parse(body || "{}");
reqPerf.mark("body-parsed");
const messages: Array<any> = Array.isArray(bodyData?.messages) ? bodyData.messages : [];
const stream = bodyData?.stream === true;
const tools = Array.isArray(bodyData?.tools) ? bodyData.tools : [];
Expand All @@ -1727,14 +1747,14 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const toolLoopGuard = createToolLoopGuard(messages, TOOL_LOOP_MAX_REPEAT);
const boundaryContext = createBoundaryRuntimeContext("node-handler");

const reqPerf = new RequestPerf(`node-${Date.now()}`);
const subagentNames = readSubagentNames();
const model = boundaryContext.run("resolveRuntimeModel", (boundary) =>
boundary.resolveRuntimeModel(bodyData?.model, bodyData?.cursorModel),
);
const authHeaderNode = req.headers["authorization"] as string | undefined;
const sdkApiKeyNode = resolveRequestSdkApiKey(authHeaderNode);
const backend = resolveBackendForRequest(sdkApiKeyNode);
reqPerf.mark("backend-resolved");
const {
prompt,
resumeChatId,
Expand Down Expand Up @@ -1773,13 +1793,13 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
sessionResume: resumeChatId ? { chatIdHash: resumeChatIdHashNode, incremental: usedIncremental } : undefined,
});

reqPerf.mark("backend-resolved");
if (backend === "sdk" && !sdkApiKeyNode) {
res.writeHead(401, { "Content-Type": "application/json" });
res.end(JSON.stringify({ error: "Cursor SDK backend requires a real Cursor API key. Set CURSOR_API_KEY or run `opencode auth login`; the legacy `cursor-agent` placeholder is not valid SDK auth." }));
return;
}

reqPerf.mark("child-create-start");
const child = createNodeChildForBackend({
backend,
sdkApiKey: sdkApiKeyNode,
Expand All @@ -1788,6 +1808,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
workspaceDirectory,
resumeChatId,
});
reqPerf.mark("child-created");

if (!stream) {
const stdoutChunks: Buffer[] = [];
Expand Down Expand Up @@ -1915,7 +1936,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const id = `cursor-acp-${Date.now()}`;
const created = Math.floor(Date.now() / 1000);
const perf = reqPerf;
perf.mark("child-spawned");
perf.mark("child-dispatched");

const converter = new StreamToSseConverter(model, { id, created });
const lineBuffer = new LineBuffer();
Expand All @@ -1925,8 +1946,17 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const stderrChunks: Buffer[] = [];
let streamTerminated = false;
let firstTokenReceived = false;
let firstStdoutByteReceived = false;
let firstSseWritten = false;
let sawSuccessfulStreamOutput = false;
let usage: OpenAiUsage | undefined;
const writeSse = (payload: string) => {
if (!firstSseWritten) {
perf.mark("first-sse-write");
firstSseWritten = true;
}
res.write(payload);
};
child.stderr.on("data", (chunk) => {
stderrChunks.push(Buffer.from(chunk));
});
Expand All @@ -1939,8 +1969,8 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const parsed = parseAgentError(errSource);
const msg = formatErrorForUser(parsed);
const errChunk = createChatCompletionChunk(id, created, model, msg, true);
res.write(`data: ${JSON.stringify(errChunk)}\n\n`);
res.write(formatSseDone());
writeSse(`data: ${JSON.stringify(errChunk)}\n\n`);
writeSse(formatSseDone());
streamTerminated = true;
res.end();
});
Expand All @@ -1958,9 +1988,9 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
boundary.createStreamToolCallChunks({ id, created, model }, toolCall),
);
for (const chunk of streamChunks) {
res.write(`data: ${JSON.stringify(chunk)}\n\n`);
writeSse(`data: ${JSON.stringify(chunk)}\n\n`);
}
res.write(formatSseDone());
writeSse(formatSseDone());
streamTerminated = true;
res.end();
try {
Expand All @@ -1974,8 +2004,8 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
return;
}
const errChunk = createChatCompletionChunk(id, created, model, message, true);
res.write(`data: ${JSON.stringify(errChunk)}\n\n`);
res.write(formatSseDone());
writeSse(`data: ${JSON.stringify(errChunk)}\n\n`);
writeSse(formatSseDone());
streamTerminated = true;
res.end();
try {
Expand Down Expand Up @@ -2033,10 +2063,10 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
responseMeta: { id, created, model },
passThroughTracker,
onToolUpdate: (update) => {
res.write(formatToolUpdateEvent(update));
writeSse(formatToolUpdateEvent(update));
},
onToolResult: (toolResult) => {
res.write(`data: ${JSON.stringify(toolResult)}\n\n`);
writeSse(`data: ${JSON.stringify(toolResult)}\n\n`);
},
onInterceptedToolCall: (toolCall) => {
emitToolCallAndTerminate(toolCall);
Expand Down Expand Up @@ -2064,7 +2094,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
sawSuccessfulStreamOutput = true;
}
for (const sse of sseChunks) {
res.write(sse);
writeSse(sse);
}
}
};
Expand All @@ -2076,6 +2106,7 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
while (chunkQueue.length > 0) {
if (streamTerminated || res.writableEnded) break;
const chunk = chunkQueue.shift()!;
if (!firstStdoutByteReceived) { perf.mark("first-stdout-byte"); firstStdoutByteReceived = true; }
if (!firstTokenReceived) { perf.mark("first-token"); firstTokenReceived = true; }
await processLines(lineBuffer.push(chunk));
}
Expand Down Expand Up @@ -2112,8 +2143,8 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
const parsed = parseAgentError(errSource);
const msg = formatErrorForUser(parsed);
const errChunk = createChatCompletionChunk(id, created, model, msg, true);
res.write(`data: ${JSON.stringify(errChunk)}\n\n`);
res.write(formatSseDone());
writeSse(`data: ${JSON.stringify(errChunk)}\n\n`);
writeSse(formatSseDone());
streamTerminated = true;
res.end();
return;
Expand Down Expand Up @@ -2144,12 +2175,12 @@ async function ensureCursorProxyServer(workspaceDirectory: string, toolRouter?:
model,
choices: [{ index: 0, delta: {}, finish_reason: "stop" }],
};
res.write(`data: ${JSON.stringify(doneChunk)}\n\n`);
writeSse(`data: ${JSON.stringify(doneChunk)}\n\n`);
if (usage) {
const usageChunk = createChatCompletionUsageChunk(id, created, model, usage);
res.write(`data: ${JSON.stringify(usageChunk)}\n\n`);
writeSse(`data: ${JSON.stringify(usageChunk)}\n\n`);
}
res.write(formatSseDone());
writeSse(formatSseDone());
streamTerminated = true;
res.end();
}
Expand Down
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