metaphorics
d66cdfbf2f
Deferred UI MCP discovery gated server-instruction inclusion on `!deferMCPDiscoveryForUI`, so both `rebuildSystemPrompt` and the `getMcpServerInstructions` signature callback omitted instructions for the lifetime of every interactive session — even after background discovery connected the servers. Server-provided instructions were dropped permanently, contradicting the changelog's "next session" claim. Both reads now depend only on `mcpManager.getServerInstructions()`, which is empty before connect and populated after, so the post-discovery `refreshMCPTools` rebuild folds them into the prompt. Corrects the changelog and adds a home-isolated deferred end-to-end regression test (stdio fixture server) that fails if the gate is reintroduced.
89 lines
3.0 KiB
TypeScript
Executable File
89 lines
3.0 KiB
TypeScript
Executable File
#!/usr/bin/env bun
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/**
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* Test fixture: a minimal, well-behaved stdio MCP server that reports
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* server-provided `instructions` on `initialize` and exposes a single tool.
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*
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* Used by `sdk-mcp-instructions.test.ts` to prove that a deferred interactive
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* (`hasUI`) session, whose MCP discovery runs in the background, still folds
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* each connected server's instructions into the system prompt once the
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* connection completes — see issue: instructions were previously dropped
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* permanently for deferred UI sessions.
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*
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* Speaks newline-delimited JSON-RPC 2.0 (the wire format of `StdioTransport`):
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* one JSON object per line on stdin, one JSON response per line on stdout.
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* Only requests (objects with an `id`) get a response; notifications are
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* dropped. Server-to-client requests are never sent — the client side only
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* needs `initialize` + `tools/list` answered to register the tool and capture
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* the instructions.
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*
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* Exported `SERVER_INSTRUCTIONS` is imported by the test for the assertion;
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* the server only starts when run as the entry module (`import.meta.main`), so
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* importing the constant never spawns a server in the test process.
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*/
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import * as readline from "node:readline";
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/** Sentinel the test greps for in the rebuilt system prompt. */
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export const SERVER_INSTRUCTIONS =
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"INSTR_FIXTURE_SENTINEL_3f9a2c: when this server is connected, always greet in Latin.";
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/** Single tool advertised by the fixture so `tools/list` is non-empty. */
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export const TOOL_NAME = "do_thing";
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type JsonRpcRequest = {
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jsonrpc: "2.0";
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id?: string | number;
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method: string;
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params?: Record<string, unknown>;
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};
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function buildResult(method: string): Record<string, unknown> {
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switch (method) {
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case "initialize":
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return {
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protocolVersion: "2025-03-26",
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serverInfo: { name: "instr-fixture", version: "1.0.0" },
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// Declare only the tools capability so the client never probes
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// resources/list or prompts/list — keeps the fixture minimal.
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capabilities: { tools: {} },
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instructions: SERVER_INSTRUCTIONS,
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};
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case "tools/list":
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return {
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tools: [
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{
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name: TOOL_NAME,
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description: "Fixture tool; never actually called by this test.",
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inputSchema: { type: "object", properties: {}, additionalProperties: false },
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},
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],
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};
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default:
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// `ping` and any other request: a benign empty result keeps the
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// transport happy without modelling methods the test never exercises.
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return {};
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}
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}
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function startServer(): void {
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const rl = readline.createInterface({ input: process.stdin });
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rl.on("line", line => {
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const trimmed = line.trim();
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if (trimmed.length === 0) return;
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let msg: JsonRpcRequest;
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try {
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msg = JSON.parse(trimmed) as JsonRpcRequest;
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} catch {
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return;
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}
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// Notifications (no `id`) get no response.
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if (msg.id === undefined || msg.id === null) return;
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const response = { jsonrpc: "2.0" as const, id: msg.id, result: buildResult(msg.method) };
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process.stdout.write(`${JSON.stringify(response)}\n`);
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});
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rl.on("close", () => process.exit(0));
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}
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if (import.meta.main) {
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startServer();
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}
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