Add and finish Pi coding-agent provider

.gitignore

@@ -32,3 +32,7 @@ node_modules/
 *.log
 .env*
 !.env.example
+
+# pi subagent + analysis scratch (not part of the change)
+.pi-subagents/
+.repos/pi-pr-analysis/

README.md

@@ -1,17 +1,18 @@
 # T3 Code
 
-T3 Code is a minimal web GUI for coding agents (currently Codex, Claude, Cursor, and OpenCode, more coming soon).
+T3 Code is a minimal web GUI for coding agents (currently Codex, Claude, Cursor, OpenCode, and Pi, more coming soon).
 
 ## Installation
 
 > [!WARNING]
-> T3 Code currently supports Codex, Claude, Cursor, and OpenCode.
+> T3 Code currently supports Codex, Claude, Cursor, OpenCode, and Pi.
 > Install and authenticate at least one provider before use:
 >
 > - Codex: install [Codex CLI](https://developers.openai.com/codex/cli) and run `codex login`
 > - Claude: install [Claude Code](https://claude.com/product/claude-code) and run `claude auth login`
 > - Cursor: install [Cursor CLI](https://cursor.com/cli) and run `cursor-agent login`
 > - OpenCode: install [OpenCode](https://opencode.ai) and run `opencode auth login`
+> - Pi: install the Pi CLI and configure a provider API key (Pi is Early Access and disabled by default — see [docs/providers/pi.md](./docs/providers/pi.md))
 
 ### Run without installing
 
@@ -77,7 +78,7 @@ curl -fsSL https://vite.plus | bash
 irm https://vite.plus/ps1 | iex
 ```
 
-Checkout their getting started guide for more information: https://viteplus.dev/guide/
+Checkout their getting started guide for more information: <https://viteplus.dev/guide/>
 
 ### Install dependencies
 

apps/server/package.json

@@ -34,6 +34,7 @@
     "node-pty": "^1.1.0"
   },
   "devDependencies": {
+    "@earendil-works/pi-coding-agent": "^0.80.10",
     "@effect/vitest": "catalog:",
     "@t3tools/contracts": "workspace:*",
     "@t3tools/shared": "workspace:*",

apps/server/scripts/cli.ts

@@ -180,6 +180,17 @@ const buildCmd = Command.make(
       const webDist = path.join(repoRoot, "apps/web/dist");
       const clientTarget = path.join(serverDir, "dist/client");
 
+      // Pi loads the approval-gate extension at runtime; vp pack won't emit it, so copy it next to the bundle.
+      const piExtensionSource = path.join(serverDir, "src/provider/assets/pi/t3-approvals.ts");
+      const piAssetTargetDir = path.join(serverDir, "dist/assets/pi");
+      if (yield* fs.exists(piExtensionSource)) {
+        yield* fs.makeDirectory(piAssetTargetDir, { recursive: true });
+        yield* fs.copyFile(piExtensionSource, path.join(piAssetTargetDir, "t3-approvals.ts"));
+        yield* Effect.log("[cli] Bundled Pi approval extension into dist/assets/pi");
+      } else {
+        return yield* new ServerCliBuildAssetMissingError({ assetPath: piExtensionSource });
+      }
+
       if (yield* fs.exists(webDist)) {
         yield* fs.copy(webDist, clientTarget);
         yield* applyDevelopmentIconOverrides(repoRoot, serverDir);

apps/server/scripts/pi-mock-rpc.ts

@@ -0,0 +1,115 @@
+#!/usr/bin/env node
+// @effect-diagnostics nodeBuiltinImport:off
+// Fake `pi --mode rpc` for tests; driven by `PI_MOCK_*` env vars.
+import * as NodeReadline from "node:readline";
+
+const assistantText = process.env["PI_MOCK_ASSISTANT_TEXT"] ?? '{"title":"Mock title"}';
+const emitInvalidJson = process.env["PI_MOCK_EMIT_INVALID_JSON"] === "1";
+const lastTextFails = process.env["PI_MOCK_LAST_TEXT_FAILS"] === "1";
+
+const replyText = emitInvalidJson
+  ? "Sure — here is the answer, with no JSON at all."
+  : assistantText;
+let lastAssistantText: string | null = null;
+
+function write(obj: unknown): void {
+  process.stdout.write(`${JSON.stringify(obj)}\n`);
+}
+
+const rl = NodeReadline.createInterface({ input: process.stdin });
+
+rl.on("line", (line: string) => {
+  const trimmed = line.trim();
+  if (!trimmed) return;
+  let command: { type?: string; id?: string };
+  try {
+    command = JSON.parse(trimmed) as { type?: string; id?: string };
+  } catch {
+    return;
+  }
+
+  switch (command.type) {
+    case "prompt":
+    case "steer":
+    case "follow_up": {
+      write({ type: "agent_start" });
+      write({ type: "turn_start" });
+      write({
+        type: "message_update",
+        assistantMessageEvent: { type: "text_delta", delta: replyText },
+      });
+      lastAssistantText = replyText;
+      write({ type: "message_end" });
+      write({ type: "turn_end" });
+      write({ type: "agent_end", willRetry: false });
+      write({ type: "agent_settled" });
+      return;
+    }
+    case "get_last_assistant_text": {
+      write(
+        lastTextFails
+          ? {
+              type: "response",
+              id: command.id,
+              command: "get_last_assistant_text",
+              success: false,
+              error: "no assistant text",
+            }
+          : {
+              type: "response",
+              id: command.id,
+              command: "get_last_assistant_text",
+              success: true,
+              data: { text: lastAssistantText },
+            },
+      );
+      return;
+    }
+    case "get_state": {
+      write({
+        type: "response",
+        id: command.id,
+        command: "get_state",
+        success: true,
+        data: {
+          sessionId: "mock-session",
+          sessionFile: "/tmp/pi-mock-session.json",
+          thinkingLevel: "off",
+          isStreaming: false,
+          isCompacting: false,
+          steeringMode: "all",
+          followUpMode: "all",
+          autoCompactionEnabled: false,
+          messageCount: 0,
+          pendingMessageCount: 0,
+        },
+      });
+      return;
+    }
+    case "get_commands": {
+      write({
+        type: "response",
+        id: command.id,
+        command: "get_commands",
+        success: true,
+        data: { commands: [] },
+      });
+      return;
+    }
+    default: {
+      if (command.id !== undefined) {
+        write({
+          type: "response",
+          id: command.id,
+          command: command.type ?? "unknown",
+          success: true,
+        });
+      }
+      return;
+    }
+  }
+});
+
+rl.on("close", () => {
+  process.exit(0);
+});

apps/server/src/provider/Drivers/PiDriver.ts

@@ -0,0 +1,169 @@
+import { PiSettings, ProviderDriverKind, type ServerProvider } from "@t3tools/contracts";
+import * as Crypto from "effect/Crypto";
+import * as Duration from "effect/Duration";
+import * as Effect from "effect/Effect";
+import * as FileSystem from "effect/FileSystem";
+import * as Path from "effect/Path";
+import * as Schema from "effect/Schema";
+import { HttpClient } from "effect/unstable/http";
+import { ChildProcessSpawner } from "effect/unstable/process";
+
+import { ServerConfig } from "../../config.ts";
+import { ServerSettingsService } from "../../serverSettings.ts";
+import { makePiTextGeneration } from "../../textGeneration/PiTextGeneration.ts";
+import { ProviderDriverError } from "../Errors.ts";
+import { makePiAdapter } from "../Layers/PiAdapter.ts";
+import { resolvePiProcessEnv } from "../Layers/PiEnvironment.ts";
+import { buildInitialPiProviderSnapshot, checkPiProviderStatus } from "../Layers/PiProvider.ts";
+import { makeManagedServerProvider } from "../makeManagedServerProvider.ts";
+import {
+  defaultProviderContinuationIdentity,
+  type ProviderDriver,
+  type ProviderInstance,
+} from "../ProviderDriver.ts";
+import type { ServerProviderDraft } from "../providerSnapshot.ts";
+import { mergeProviderInstanceEnvironment } from "../ProviderInstanceEnvironment.ts";
+import {
+  enrichProviderSnapshotWithVersionAdvisory,
+  makePackageManagedProviderMaintenanceResolver,
+  resolveProviderMaintenanceCapabilitiesEffect,
+} from "../providerMaintenance.ts";
+import {
+  haveProviderSnapshotSettingsChanged,
+  makeProviderSnapshotSettingsSource,
+  type ProviderSnapshotSettings,
+} from "../providerUpdateSettings.ts";
+
+const decodePiSettings = Schema.decodeSync(PiSettings);
+
+const DRIVER_KIND = ProviderDriverKind.make("pi");
+const SNAPSHOT_REFRESH_INTERVAL = Duration.minutes(5);
+
+const UPDATE = makePackageManagedProviderMaintenanceResolver({
+  provider: DRIVER_KIND,
+  npmPackageName: "@earendil-works/pi-coding-agent",
+  homebrewFormula: null,
+  nativeUpdate: null,
+});
+
+export type PiDriverEnv =
+  | ChildProcessSpawner.ChildProcessSpawner
+  | Crypto.Crypto
+  | FileSystem.FileSystem
+  | HttpClient.HttpClient
+  | Path.Path
+  | ServerConfig
+  | ServerSettingsService;
+
+const withInstanceIdentity =
+  (input: {
+    readonly instanceId: ProviderInstance["instanceId"];
+    readonly displayName: string | undefined;
+    readonly accentColor: string | undefined;
+    readonly continuationGroupKey: string;
+  }) =>
+  (snapshot: ServerProviderDraft): ServerProvider => ({
+    ...snapshot,
+    instanceId: input.instanceId,
+    driver: DRIVER_KIND,
+    ...(input.displayName ? { displayName: input.displayName } : {}),
+    ...(input.accentColor ? { accentColor: input.accentColor } : {}),
+    continuation: { groupKey: input.continuationGroupKey },
+  });
+
+export const PiDriver: ProviderDriver<PiSettings, PiDriverEnv> = {
+  driverKind: DRIVER_KIND,
+  metadata: {
+    displayName: "Pi",
+    supportsMultipleInstances: true,
+  },
+  configSchema: PiSettings,
+  defaultConfig: (): PiSettings => decodePiSettings({}),
+  create: ({ instanceId, displayName, accentColor, environment, enabled, config }) =>
+    Effect.gen(function* () {
+      const spawner = yield* ChildProcessSpawner.ChildProcessSpawner;
+      const httpClient = yield* HttpClient.HttpClient;
+      const serverSettings = yield* ServerSettingsService;
+      const serverConfig = yield* ServerConfig;
+      const effectiveConfig = { ...config, enabled } satisfies PiSettings;
+      const processEnv = resolvePiProcessEnv(
+        effectiveConfig,
+        mergeProviderInstanceEnvironment(environment),
+      );
+      const continuationIdentity = defaultProviderContinuationIdentity({
+        driverKind: DRIVER_KIND,
+        instanceId,
+      });
+      const stampIdentity = withInstanceIdentity({
+        instanceId,
+        displayName,
+        accentColor,
+        continuationGroupKey: continuationIdentity.continuationKey,
+      });
+      const maintenanceCapabilities = yield* resolveProviderMaintenanceCapabilitiesEffect(UPDATE, {
+        binaryPath: effectiveConfig.binaryPath,
+        env: processEnv,
+      });
+
+      const adapter = yield* makePiAdapter(effectiveConfig, {
+        instanceId,
+        environment: processEnv,
+      });
+      const textGeneration = yield* makePiTextGeneration(effectiveConfig, processEnv);
+
+      const checkProvider = checkPiProviderStatus(
+        effectiveConfig,
+        serverConfig.cwd,
+        processEnv,
+      ).pipe(
+        Effect.map(stampIdentity),
+        Effect.provideService(ChildProcessSpawner.ChildProcessSpawner, spawner),
+      );
+
+      const snapshotSettings = makeProviderSnapshotSettingsSource(effectiveConfig, serverSettings);
+      const snapshot = yield* makeManagedServerProvider<ProviderSnapshotSettings<PiSettings>>({
+        maintenanceCapabilities,
+        getSettings: snapshotSettings.getSettings,
+        streamSettings: snapshotSettings.streamSettings,
+        haveSettingsChanged: haveProviderSnapshotSettingsChanged,
+        initialSnapshot: (settings) =>
+          buildInitialPiProviderSnapshot(settings.provider).pipe(Effect.map(stampIdentity)),
+        checkProvider,
+        enrichSnapshot: ({ settings, snapshot: currentSnapshot, publishSnapshot }) =>
+          enrichProviderSnapshotWithVersionAdvisory(currentSnapshot, maintenanceCapabilities, {
+            enableProviderUpdateChecks: settings.enableProviderUpdateChecks,
+          }).pipe(
+            Effect.provideService(HttpClient.HttpClient, httpClient),
+            Effect.flatMap((enrichedSnapshot) => publishSnapshot(enrichedSnapshot)),
+            Effect.catchCause((cause) =>
+              Effect.logWarning("Pi version advisory enrichment failed", { cause }).pipe(
+                Effect.asVoid,
+              ),
+            ),
+          ),
+        refreshInterval: SNAPSHOT_REFRESH_INTERVAL,
+      }).pipe(
+        Effect.mapError(
+          (cause) =>
+            new ProviderDriverError({
+              driver: DRIVER_KIND,
+              instanceId,
+              detail: `Failed to build Pi snapshot: ${cause.message ?? String(cause)}`,
+              cause,
+            }),
+        ),
+      );
+
+      return {
+        instanceId,
+        driverKind: DRIVER_KIND,
+        continuationIdentity,
+        displayName,
+        accentColor,
+        enabled,
+        snapshot,
+        adapter,
+        textGeneration,
+      } satisfies ProviderInstance;
+    }),
+};