chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/agent/test/harness/prompt-templates.test.ts

@@ -0,0 +1,97 @@
+import { symlink } from "node:fs/promises";
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+import { BACKGROUND_CONTEXT } from "../../src/harness/context.ts";
+import { NodeExecutionEnv } from "../../src/harness/env/nodejs.ts";
+import {
+	formatPromptTemplateInvocation,
+	loadPromptTemplates,
+	loadSourcedPromptTemplates,
+} from "../../src/harness/prompt-templates.ts";
+import { createTempDir } from "./session-test-utils.ts";
+
+describe("loadPromptTemplates", () => {
+	it("loads markdown templates non-recursively from one or more dirs", async () => {
+		const root = createTempDir();
+		const env = new NodeExecutionEnv({ cwd: root });
+		await env.createDir("a/nested", { recursive: true }, BACKGROUND_CONTEXT);
+		await env.createDir("b", { recursive: true }, BACKGROUND_CONTEXT);
+		await env.writeFile("a/one.md", "---\ndescription: One template\n---\nHello $1", BACKGROUND_CONTEXT);
+		await env.writeFile("a/nested/ignored.md", "Ignored", BACKGROUND_CONTEXT);
+		await env.writeFile("b/two.md", "First line description\nBody", BACKGROUND_CONTEXT);
+
+		const { promptTemplates, diagnostics } = await loadPromptTemplates(env, ["a", "b"], BACKGROUND_CONTEXT);
+
+		expect(diagnostics).toEqual([]);
+		expect(promptTemplates).toEqual([
+			{ name: "one", description: "One template", content: "Hello $1" },
+			{ name: "two", description: "First line description", content: "First line description\nBody" },
+		]);
+	});
+
+	it("preserves source info for sourced prompt templates", async () => {
+		const root = createTempDir();
+		const env = new NodeExecutionEnv({ cwd: root });
+		await env.createDir("prompts", { recursive: true }, BACKGROUND_CONTEXT);
+		await env.writeFile("prompts/example.md", "---\ndescription: Example\n---\nExample body", BACKGROUND_CONTEXT);
+
+		const { promptTemplates, diagnostics } = await loadSourcedPromptTemplates(
+			env,
+			[{ path: "prompts", source: { type: "project" as const } }],
+			undefined,
+			BACKGROUND_CONTEXT,
+		);
+
+		expect(diagnostics).toEqual([]);
+		expect(promptTemplates).toEqual([
+			{
+				promptTemplate: { name: "example", description: "Example", content: "Example body" },
+				source: { type: "project" },
+			},
+		]);
+	});
+
+	it("attaches source info to diagnostics", async () => {
+		const root = createTempDir();
+		const env = new NodeExecutionEnv({ cwd: root });
+		await env.writeFile("broken.md", "---\ndescription: [unterminated\n---\nBody", BACKGROUND_CONTEXT);
+
+		const { promptTemplates, diagnostics } = await loadSourcedPromptTemplates(
+			env,
+			[{ path: "broken.md", source: { type: "user" as const } }],
+			undefined,
+			BACKGROUND_CONTEXT,
+		);
+
+		expect(promptTemplates).toEqual([]);
+		expect(diagnostics).toHaveLength(1);
+		expect(diagnostics[0]).toMatchObject({
+			type: "warning",
+			path: join(root, "broken.md"),
+			source: { type: "user" },
+		});
+	});
+
+	it("loads explicit markdown files and symlinked files", async () => {
+		const root = createTempDir();
+		const env = new NodeExecutionEnv({ cwd: root });
+		await env.writeFile("target.md", "---\ndescription: Target\n---\nTarget body", BACKGROUND_CONTEXT);
+		await symlink(join(root, "target.md"), join(root, "link.md"));
+
+		const { promptTemplates } = await loadPromptTemplates(env, ["target.md", "link.md"], BACKGROUND_CONTEXT);
+
+		expect(promptTemplates).toEqual([
+			{ name: "target", description: "Target", content: "Target body" },
+			{ name: "link", description: "Target", content: "Target body" },
+		]);
+	});
+});
+
+describe("formatPromptTemplateInvocation", () => {
+	it("substitutes command arguments", () => {
+		const content = "$1 $" + "{@:2} $ARGUMENTS";
+		expect(formatPromptTemplateInvocation({ name: "one", content }, ["hello world", "test"])).toBe(
+			"hello world test hello world test",
+		);
+	});
+});