feat(ai,agent,coding-agent): move client identity and provider attribution into pi-ai

pi-ai gets a ClientIdentity request option and createModels() default that choose the User-Agent (detailed with version, short, or custom) and provider attribution headers for OpenRouter, NVIDIA NIM, and OpenCode. Attribution is off by default in pi-ai and on by default in pi-agent-core and pi-durable (HarnessOptions.identity). pi-coding-agent sets its identity from the telemetry setting instead of adding headers itself.

packages/durable/test/chat-support.ts

@@ -31,6 +31,8 @@ export type ChatSetup = {
 	/** Live Harness settings; tests assign fields to change them between decisions. */
 	readonly settings: { -readonly [K in keyof HarnessSettings]: HarnessSettings[K] };
 	now: () => number;
+	/** `HarnessOptions.identity`. */
+	identity?: HarnessOptions["identity"];
 };
 
 export function chatSetup(options: RegisterFauxProviderOptions = {}): ChatSetup {
@@ -53,6 +55,7 @@ export async function openChat(
 			models: setup.models,
 			registry: setup.registry,
 			settings: setup.settings,
+			...(setup.identity === undefined ? {} : { identity: setup.identity }),
 			...(options.env === undefined
 				? {}
 				: { env: typeof options.env === "function" ? options.env : () => options.env as ExecutionEnv }),

packages/durable/test/harness-generation.test.ts

@@ -385,6 +385,24 @@ describe("generation", () => {
 		await harness.close(context);
 	});
 
+	it("attributes model requests to pi by default and merges the Harness identity over it", async () => {
+		const seen: (SimpleStreamOptions["identity"] | undefined)[] = [];
+		const capture = (_context: unknown, options?: SimpleStreamOptions) => {
+			seen.push(options?.identity);
+			return fauxAssistantMessage("ok");
+		};
+		for (const identity of [undefined, { userAgent: "short" as const, attribution: "acme" }]) {
+			const setup = chatSetup();
+			setup.identity = identity;
+			setup.faux.setResponses([capture]);
+			const { harness, root } = await openChat(new MemoryStorage(), setup);
+			harness.resume();
+			await (await root.submit({ type: "input", content: "hi" }, context)).wait(context);
+			await harness.close(context);
+		}
+		expect(seen).toEqual([{ attribution: true }, { attribution: "acme", userAgent: "short" }]);
+	});
+
 	// Regression coverage for #10424.
 	it("keeps provider session IDs request-local across concurrent conversations", async () => {
 		const setup = chatSetup();

packages/durable/test/harness-host-inputs.test.ts

@@ -74,6 +74,8 @@ describe("HarnessOptions.models and settings as functions", () => {
 		]);
 		first.setProvider(faux.provider);
 		second.setProvider(faux.provider);
+		// Marks the second Models: tools see views of the host's Models that add the Harness identity.
+		second.setProvider(fauxProvider({ provider: "second-only" }).provider);
 		let current = first;
 		const seen: Models[] = [];
 		const registry = createRegistry();
@@ -97,9 +99,8 @@ describe("HarnessOptions.models and settings as functions", () => {
 		);
 		const { harness, root } = await open({ models: () => current }, registry);
 		expect(await turn(root, "go")).toBe("done");
-		expect(seen).toEqual([first, second]);
-		expect(seen[0]).toBe(first);
-		expect(seen[1]).toBe(second);
+		expect(seen[0]!.getProvider("second-only")).toBeUndefined();
+		expect(seen[1]!.getProvider("second-only")).toBeDefined();
 		await harness.close(context);
 	});
 

packages/durable/test/harness-tools.test.ts

@@ -8,6 +8,7 @@ import {
 	fauxAssistantMessage,
 	fauxText,
 	fauxToolCall,
+	type Models,
 	type SystemMessage,
 	type ToolResultMessage,
 	Type,
@@ -130,8 +131,10 @@ describe("tool round", () => {
 		});
 		const { harness, status } = await run(setup, [calls(["echo", {}, "c1"]), DONE]);
 		expect(status).toBe("done");
-		expect(seen).toEqual([setup.models, setup.models]);
-		expect(seen.every((models) => models === setup.models)).toBe(true);
+		// One view of the host's Models that adds the Harness identity, shared by tools and hooks.
+		expect(seen).toHaveLength(2);
+		expect(seen[0]).toBe(seen[1]);
+		expect((seen[0] as Models).getProviders()).toEqual(setup.models.getProviders());
 		await harness.close(context);
 	});