fix(pi): honor the host configuration directory for global settings

src/plugins/pi/content/README.md

@@ -74,9 +74,14 @@ package name when needed.
 Settings load in this order, with later values taking precedence:
 
 1. Defaults
-2. `~/.pi/agent/braintrust.json`
-3. `.pi/braintrust.json` in the project (or Pi's configured project config directory)
-4. `bt trace run` settings for that invocation
+2. `~/.pi/agent/braintrust.json`, the file `bt trace enable pi` writes
+3. `braintrust.json` in the running host's agent directory, when it differs from `~/.pi/agent`
+4. `.pi/braintrust.json` in the project (or the running host's configured config directory)
+5. `bt trace run` settings for that invocation
+
+A host package's `piConfig.configDir` replaces `.pi` in steps 3 and 4. A host that
+sets `PI_CODING_AGENT_DIR` (for example, for named profiles) uses that directory in
+step 3.
 
 Example:
 

src/plugins/pi/content/src/config.test.ts

@@ -1,7 +1,7 @@
 import { mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { dirname, join } from "node:path";
-import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { loadConfig } from "./config.ts";
 
 const ENVIRONMENT_KEYS = [
@@ -13,6 +13,7 @@ const ENVIRONMENT_KEYS = [
   "BRAINTRUST_SHOW_TRACE_LINK",
   "TRACE_TO_BRAINTRUST",
   "BT_TRACE_INVOCATION_SETTINGS",
+  "PI_CODING_AGENT_DIR",
 ] as const;
 
 const originalEnvironment = new Map<string, string | undefined>();
@@ -105,6 +106,59 @@ describe("loadConfig", () => {
     });
   });
 
+  it("honors the host's explicit agent directory without changing project precedence", () => {
+    process.env.PI_CODING_AGENT_DIR = join(home, ".omp", "profiles", "work", "agent");
+    writeJson(join(process.env.PI_CODING_AGENT_DIR, "braintrust.json"), {
+      trace_to_braintrust: true,
+      profile: "host-profile",
+      project: "profile-project",
+    });
+    expect(loadConfig(cwd)).toMatchObject({
+      enabled: true,
+      profile: "host-profile",
+      projectName: "profile-project",
+    });
+    writeJson(join(cwd, ".pi", "braintrust.json"), { project: "project-override" });
+    expect(loadConfig(cwd)).toMatchObject({
+      profile: "host-profile",
+      projectName: "project-override",
+    });
+  });
+
+  it("uses the running host's config directory for global and project settings", async () => {
+    vi.doMock("./pi-package.ts", () => ({
+      runningPiPackage: () => ({ configDir: ".omp", version: "18.12.6" }),
+    }));
+    vi.resetModules();
+    try {
+      // Reload the module boundary so its cached config directory sees this host.
+      const { loadConfig: loadHostConfig } = await import("./config.ts");
+      // `bt trace enable pi` writes Pi's global file; hosts still honor it.
+      writeJson(join(home, ".pi", "agent", "braintrust.json"), {
+        trace_to_braintrust: true,
+        project: "bt-written",
+      });
+      expect(loadHostConfig(cwd)).toMatchObject({ enabled: true, projectName: "bt-written" });
+      writeJson(join(home, ".omp", "agent", "braintrust.json"), {
+        profile: "host-profile",
+        project: "host-project",
+      });
+      expect(loadHostConfig(cwd)).toMatchObject({
+        enabled: true,
+        profile: "host-profile",
+        projectName: "host-project",
+      });
+      writeJson(join(cwd, ".omp", "braintrust.json"), { project: "project-override" });
+      expect(loadHostConfig(cwd)).toMatchObject({
+        profile: "host-profile",
+        projectName: "project-override",
+      });
+    } finally {
+      vi.doUnmock("./pi-package.ts");
+      vi.resetModules();
+    }
+  });
+
   it("prefers a canonical route over stale top-level routing", () => {
     writeJson(join(home, ".pi", "agent", "braintrust.json"), {
       trace_to_braintrust: true,

src/plugins/pi/content/src/config.ts

@@ -1,6 +1,6 @@
 import { existsSync, readFileSync } from "node:fs";
 import { homedir } from "node:os";
-import { join } from "node:path";
+import { join, resolve } from "node:path";
 import { type DaemonSessionRoute, resolveDaemonTraceSettings } from "./runtime/daemon-client.ts";
 import { runningPiPackage } from "./pi-package.ts";
 
@@ -17,7 +17,7 @@ export interface PiConfig {
 
 type ConfigRecord = Record<string, unknown>;
 
-const PROJECT_CONFIG_DIR_NAME = runningPiPackage().configDir;
+const CONFIG_DIR_NAME = runningPiPackage().configDir;
 
 function record(value: unknown): ConfigRecord | undefined {
   return value !== null && typeof value === "object" && !Array.isArray(value)
@@ -101,8 +101,15 @@ export function loadConfig(cwd = process.cwd()): PiConfig {
     },
   };
 
-  applyConfig(config, readConfig(join(homedir(), ".pi", "agent", "braintrust.json")));
-  applyConfig(config, readConfig(join(cwd, PROJECT_CONFIG_DIR_NAME, "braintrust.json")));
+  // `bt trace enable pi` writes Pi's global file, so it stays the base layer. A host
+  // with its own agent directory layers its settings on top.
+  const piAgentDir = join(homedir(), ".pi", "agent");
+  const hostAgentDir = process.env.PI_CODING_AGENT_DIR || join(homedir(), CONFIG_DIR_NAME, "agent");
+  applyConfig(config, readConfig(join(piAgentDir, "braintrust.json")));
+  if (resolve(hostAgentDir) !== resolve(piAgentDir)) {
+    applyConfig(config, readConfig(join(hostAgentDir, "braintrust.json")));
+  }
+  applyConfig(config, readConfig(join(cwd, CONFIG_DIR_NAME, "braintrust.json")));
 
   config.showUi = boolean(process.env.BRAINTRUST_SHOW_UI) ?? config.showUi;
   config.showTraceLink = boolean(process.env.BRAINTRUST_SHOW_TRACE_LINK) ?? config.showTraceLink;