feat: add prompt routing and terminal preset

tests/tool-routing.test.ts

@@ -0,0 +1,89 @@
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+import assert from "node:assert/strict";
+import { mkdtemp, readFile, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import test from "node:test";
+
+import toolRoutingExtension, {
+	appendToolRouting,
+	buildToolRoutingSection,
+	getSystemPromptDumpPath,
+} from "../extensions/tool-routing.ts";
+
+test("search routing narrows files before requesting matching line numbers", () => {
+	const section = buildToolRoutingSection(["find", "grep", "read"]);
+
+	assert.match(section, /Use find to identify likely files or directories/);
+	assert.match(section, /Use grep or multi_grep only inside the narrowed path or file/);
+	assert.match(section, /obtain matching line numbers/);
+	assert.match(section, /narrow the path, glob, or pattern instead of increasing the limit/);
+	assert.match(section, /Use read with offset\/limit only for the exact matching region/);
+});
+
+test("routing includes only guidance for active optional tools", () => {
+	const section = buildToolRoutingSection(["read"]);
+
+	assert.doesNotMatch(section, /codegraph_explore first/);
+	assert.doesNotMatch(section, /For literal search/);
+	assert.doesNotMatch(section, /Use Context Mode/);
+	assert.match(section, /Use read directly/);
+});
+
+test("routing is appended once", () => {
+	const once = appendToolRouting("base prompt", ["find", "grep"]);
+	const twice = appendToolRouting(once, ["find", "grep"]);
+
+	assert.equal(twice, once);
+	assert.equal((once.match(/<!-- my-pi-tool-routing -->/g) ?? []).length, 1);
+});
+
+test("dump path stays under the current project", () => {
+	assert.equal(
+		getSystemPromptDumpPath("/workspace/project"),
+		"/workspace/project/.pi-debug/effective-system-prompt.md",
+	);
+});
+
+test("dump-system-prompt writes the last routed prompt seen by the extension", async () => {
+	let beforeAgentStart: ((event: any) => { systemPrompt: string }) | undefined;
+	let command: { handler: (args: string, ctx: any) => Promise<void> } | undefined;
+	const pi = {
+		on(name: string, handler: typeof beforeAgentStart) {
+			if (name === "before_agent_start") beforeAgentStart = handler;
+		},
+		registerCommand(_name: string, definition: typeof command) {
+			command = definition;
+		},
+	} as unknown as ExtensionAPI;
+	toolRoutingExtension(pi);
+	assert.ok(beforeAgentStart);
+	assert.ok(command);
+	beforeAgentStart({
+		systemPrompt: "prompt already modified by an earlier extension",
+		systemPromptOptions: { selectedTools: ["find", "grep"] },
+	});
+
+	const cwd = await mkdtemp(join(tmpdir(), "my-pi-tool-routing-"));
+	try {
+		let notification = "";
+		await command.handler("", {
+			cwd,
+			getSystemPrompt: () => "base prompt",
+			getSystemPromptOptions: () => ({ selectedTools: ["find", "grep"] }),
+			ui: {
+				notify(message: string) {
+					notification = message;
+				},
+			},
+		});
+
+		const outputPath = getSystemPromptDumpPath(cwd);
+		const dumped = await readFile(outputPath, "utf8");
+		assert.match(dumped, /^prompt already modified by an earlier extension/);
+		assert.match(dumped, /<!-- my-pi-tool-routing -->/);
+		assert.match(notification, new RegExp(outputPath.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")));
+	} finally {
+		await rm(cwd, { recursive: true, force: true });
+	}
+});