fix(pi): report the running host package instead of an installed peer

bt-daemon/docs/protocol.md

@@ -271,6 +271,11 @@ coding-agent span falls back to Rust SDK provenance. Transcript backfills captur
 versions available at materialization, not unrecorded historical versions. See the
 [span-origin contract](../../docs/coding-agent-tracing-plugin-spec.md#621-span-origin-versions).
 
+Pi-compatible hosts retain the canonical transport source `pi` so they share its
+translator. The Pi extension sends the running host package's version as
+`source_version` and its package name as `payload.host_name`. The translator records
+`metadata.host_name`; the session-root label remains `Pi` for every Pi-compatible host.
+
 For acknowledged spans from legacy ledgers without saved snapshots, stateless
 updates omit `context.span_origin` entirely, including SDK defaults and inherited
 parent origin fields. This preserves existing backend provenance without guessing

bt-daemon/src/translate/pi.rs

@@ -573,6 +573,14 @@ impl PiTranslator {
             metadata.insert("model".into(), json!(model));
         }
         metadata.insert("pi_version".into(), json!(envelope.source_version));
+        if let Some(host_name) = envelope
+            .payload
+            .get("host_name")
+            .and_then(Value::as_str)
+            .filter(|name| !name.is_empty())
+        {
+            metadata.insert("host_name".into(), json!(host_name));
+        }
         metadata.insert(
             "extension_version".into(),
             envelope

bt-daemon/tests/pi_translator.rs

@@ -72,6 +72,33 @@ fn reduce(ops: Vec<SpanOp>) -> HashMap<String, SpanRow> {
     rows
 }
 
+#[test]
+fn pi_records_the_running_host_identity() {
+    let registry = Registry::default_agents();
+    let mut translator = registry.create("pi", "pi-session");
+    let ctx = SessionCtx {
+        session_id: "pi-session".into(),
+        config: None,
+    };
+    let mut start = event("session_start", 1, json!({"reason":"new"}));
+    start.source_version = Some("18.12.6".into());
+    start.payload["host_name"] = json!("@oh-my-pi/pi-coding-agent");
+    let ops = translator.handle(&start, &ctx).unwrap();
+    let root = ops
+        .iter()
+        .find_map(|op| match op {
+            SpanOp::Insert(row) if row.parent_span_ids.is_empty() => Some(row),
+            _ => None,
+        })
+        .unwrap();
+    assert_eq!(root.name, "Pi");
+    assert_eq!(
+        root.metadata.as_ref().unwrap()["host_name"],
+        "@oh-my-pi/pi-coding-agent"
+    );
+    assert_eq!(root.metadata.as_ref().unwrap()["pi_version"], "18.12.6");
+}
+
 #[test]
 fn pi_builds_turn_llm_tool_compaction_and_shutdown_spans() {
     let registry = Registry::default_agents();

src/plugins/pi/content/README.md

@@ -69,6 +69,11 @@ from each of the last five stable Pi release lines. The compatibility job
 resolves these versions on each run, including releases from Pi's former npm
 package name when needed.
 
+Package detection prefers the running CLI to an extension-local peer dependency.
+Pi-compatible hosts are recognized by a `piConfig` field or a known package name,
+including Oh My Pi (`@oh-my-pi/pi-coding-agent`). The trace records the host
+package name in `metadata.host_name` and its version in `metadata.pi_version`.
+
 ## Configuration
 
 Settings load in this order, with later values taking precedence:

src/plugins/pi/content/src/daemon-adapter.test.ts

@@ -70,6 +70,14 @@ vi.mock("./legacy-session.ts", () => ({
   },
 }));
 
+vi.mock("./pi-package.ts", () => ({
+  runningPiPackage: () => ({
+    name: "@oh-my-pi/pi-coding-agent",
+    version: "18.12.6",
+    configDir: ".pi",
+  }),
+}));
+
 type Handler = (...args: unknown[]) => Promise<unknown>;
 
 /** Load the extension against a fake Pi and return its registered handlers. */
@@ -112,6 +120,16 @@ describe("Pi daemon adapter", () => {
     expect(handlers.size).toBe(0);
   });
 
+  it("forwards the running host name and version instead of an installed peer", async () => {
+    const handlers = await loadExtension();
+    await handlers.get("session_start")?.({ reason: "new" }, fakeContext());
+    expect(mockState.logs[0]).toMatchObject({
+      source: "pi",
+      source_version: "18.12.6",
+      payload: { host_name: "@oh-my-pi/pi-coding-agent" },
+    });
+  });
+
   it("does not block session startup on daemon status", async () => {
     const ctx = fakeContext();
     const handlers = await loadExtension();

src/plugins/pi/content/src/index.ts

@@ -11,6 +11,7 @@ const STATUS_KEY = "braintrust-tracing";
 const WIDGET_KEY = "braintrust-trace-link";
 const UI_STATUS_TIMEOUT_MS = 250;
 const PI_VERSION = runningPiPackage().version;
+const PI_HOST_NAME = runningPiPackage().name;
 
 function sessionKeyFor(
   sessionFile: string | undefined,
@@ -145,6 +146,7 @@ export default function braintrustPiExtension(pi: ExtensionAPI): void {
       payload: {
         event: nativePayload(event),
         extension_version: EXTENSION_VERSION,
+        host_name: PI_HOST_NAME,
         session_file: descriptor?.sessionFile,
         native_session_id: descriptor?.nativeSessionId,
         legacy_resume: legacyContinuation,

src/plugins/pi/content/src/pi-package.test.ts

@@ -42,7 +42,7 @@ describe("loadPiPackageMetadata", () => {
         symlinkSync(installPi(`node_modules/${PI}`, { name: PI, version: "1.0.0" }), bin);
         return [bin];
       },
-      { version: "1.0.0", configDir: ".pi" },
+      { name: PI, version: "1.0.0", configDir: ".pi" },
     ],
     [
       "a fork with its own name and config directory",
@@ -53,23 +53,23 @@ describe("loadPiPackageMetadata", () => {
           piConfig: { configDir: ".acme" },
         }),
       ],
-      { version: "3.2.1", configDir: ".acme" },
+      { name: "@acme/agent", version: "3.2.1", configDir: ".acme" },
     ],
     [
       "a PI_PACKAGE_DIR override",
       () => {
         installPi("store/pi", { name: PI, version: "1.0.0" });
         return [join(root, "store", "pi", "package.json"), join(root, "store", "bin")];
       },
-      { version: "1.0.0", configDir: ".pi" },
+      { name: PI, version: "1.0.0", configDir: ".pi" },
     ],
     [
       "a Bun-compiled binary with package.json beside it",
       () => {
         writeJson(join(root, "pi-linux-x64", "package.json"), { name: PI, version: "1.0.0" });
         return [undefined, "/$bunfs/root/pi", join(root, "pi-linux-x64", "pi")];
       },
-      { version: "1.0.0", configDir: ".pi" },
+      { name: PI, version: "1.0.0", configDir: ".pi" },
     ],
     [
       "an SDK application that depends on Pi",
@@ -78,17 +78,47 @@ describe("loadPiPackageMetadata", () => {
         const pi = installPi(`app/node_modules/${PI}`, { name: PI, version: "0.99.2" });
         return [join(root, "app", "main.js"), pi];
       },
-      { version: "0.99.2", configDir: ".pi" },
+      { name: PI, version: "0.99.2", configDir: ".pi" },
     ],
     [
       "no discoverable Pi",
       () => [join(root, "missing.js")],
-      { version: undefined, configDir: ".pi" },
+      { name: undefined, version: undefined, configDir: ".pi" },
     ],
   ])("finds %s", (_name, setup, expected) => {
     expect(loadPiPackageMetadata(setup())).toEqual(expected);
   });
 
+  it("prefers OMP's running manifest over an auto-installed upstream peer", () => {
+    const host = installPi("omp", {
+      name: "@oh-my-pi/pi-coding-agent",
+      version: "18.12.6",
+      bin: { omp: "dist/cli.js" },
+    });
+    const peer = installPi(`plugins/node_modules/${PI}`, { name: PI, version: "1.4.0" });
+    // Recognizing OMP must not move the extension's existing `.pi` settings.
+    expect(loadPiPackageMetadata([host, peer])).toEqual({
+      name: "@oh-my-pi/pi-coding-agent",
+      version: "18.12.6",
+      configDir: ".pi",
+    });
+  });
+
+  it("reports the embedded Pi for an SDK application's own CLI", () => {
+    const app = installPi("app", {
+      name: "acme-agent",
+      version: "0.3.0",
+      bin: { acme: "dist/cli.js" },
+      dependencies: { [PI]: "^1.4.0" },
+    });
+    const pi = installPi(`app/node_modules/${PI}`, { name: PI, version: "1.4.0" });
+    expect(loadPiPackageMetadata([app, pi])).toEqual({
+      name: PI,
+      version: "1.4.0",
+      configDir: ".pi",
+    });
+  });
+
   it("resolves the installed Pi development dependency through ESM conditions", () => {
     const metadata = loadPiPackageMetadata([resolvePiPackage()]);
     expect(metadata.version).toMatch(/^\d+\.\d+\.\d+/);

src/plugins/pi/content/src/pi-package.ts

@@ -4,7 +4,11 @@ import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 
 const PI_PACKAGE = "@earendil-works/pi-coding-agent";
-const PI_PACKAGE_NAMES = new Set([PI_PACKAGE, "@mariozechner/pi-coding-agent"]);
+const PI_PACKAGE_NAMES = new Set([
+  PI_PACKAGE,
+  "@mariozechner/pi-coding-agent",
+  "@oh-my-pi/pi-coding-agent",
+]);
 
 interface PiPackageManifest {
   name?: unknown;
@@ -15,6 +19,7 @@ interface PiPackageManifest {
 }
 
 export interface PiPackageMetadata {
+  name?: string;
   version?: string;
   configDir: string;
 }
@@ -37,6 +42,7 @@ export function loadPiPackageMetadata(candidates: (string | undefined)[]): PiPac
     if (manifest) break;
   }
   return {
+    name: typeof manifest?.name === "string" ? manifest.name : undefined,
     version: typeof manifest?.version === "string" ? manifest.version : undefined,
     configDir:
       typeof manifest?.piConfig?.configDir === "string" ? manifest.piConfig.configDir : ".pi",