Pi 0.65.0

New Features

• Session runtime API: createAgentSessionRuntime() and AgentSessionRuntime provide a closure-based runtime that recreates cwd-bound services and session config on every session switch. Startup, /new, /resume, /fork, and import all use the same creation path. See docs/sdk.md and examples/sdk/13-session-runtime.ts.
• Label timestamps in /tree: Toggle timestamps on tree entries with Shift+T, with smart date formatting and timestamp preservation through branching (#2691 by @w-winter)
• defineTool() helper: Create standalone custom tool definitions with full TypeScript parameter type inference, no manual casts needed (#2746). See docs/extensions.md.
• Unified diagnostics: Arg parsing, service creation, session option resolution, and resource loading all return structured diagnostics (info/warning/error) instead of logging or exiting. The app layer decides presentation and exit behavior.

Breaking Changes

• Removed extension post-transition events session_switch and session_fork. Use session_start with event.reason ("startup" | "reload" | "new" | "resume" | "fork"). For "new", "resume", and "fork", session_start includes previousSessionFile.
• Removed session-replacement methods from AgentSession. Use AgentSessionRuntime for newSession(), switchSession(), fork(), and importFromJsonl(). Cross-cwd session replacement rebuilds all cwd-bound runtime state and replaces the live AgentSession instance.
• Removed session_directory from extension and settings APIs.
• Unknown single-dash CLI flags (e.g. -s) now produce an error instead of being silently ignored.

Migration: Extensions

Before:

pi.on("session_switch", async (event, ctx) => { ... });
pi.on("session_fork", async (_event, ctx) => { ... });

After:

pi.on("session_start", async (event, ctx) => {
  // event.reason: "startup" | "reload" | "new" | "resume" | "fork"
  // event.previousSessionFile: set for "new", "resume", "fork"
});

Migration: SDK session replacement

Before:

await session.newSession();
await session.switchSession("/path/to/session.jsonl");

After:

import {
  type CreateAgentSessionRuntimeFactory,
  createAgentSessionFromServices,
  createAgentSessionRuntime,
  createAgentSessionServices,
  getAgentDir,
  SessionManager,
} from "@mariozechner/pi-coding-agent";

const createRuntime: CreateAgentSessionRuntimeFactory = async ({ cwd, sessionManager, sessionStartEvent }) => {
  const services = await createAgentSessionServices({ cwd });
  return {
    ...(await createAgentSessionFromServices({ services, sessionManager, sessionStartEvent })),
    services,
    diagnostics: services.diagnostics,
  };
};

const runtime = await createAgentSessionRuntime(createRuntime, {
  cwd: process.cwd(),
  agentDir: getAgentDir(),
  sessionManager: SessionManager.create(process.cwd()),
});

await runtime.newSession();
await runtime.switchSession("/path/to/session.jsonl");
await runtime.fork("entry-id");

// After replacement, runtime.session is the new live session.
// Rebind any session-local subscriptions or extension bindings.

Added

• Added createAgentSessionRuntime() and AgentSessionRuntime for runtime-backed session replacement. The runtime takes a CreateAgentSessionRuntimeFactory closure that closes over process-global fixed inputs and recreates cwd-bound services and session config for each effective cwd. Startup and later /new, /resume, /fork, import all use the same factory.

• Added unified diagnostics model (info/warning/error) for arg parsing, service creation, session option resolution, and resource loading. Creation logic no longer logs or exits. The app layer decides presentation and exit behavior.

• Added error diagnostics for missing explicit CLI resource paths (-e, --skill, --prompt-template, --theme)

• Added defineTool() so standalone and array-based custom tool definitions keep inferred parameter types without manual casts (#2746)

• Added label timestamps to the session tree with a Shift+T toggle in /tree, smart date formatting, and timestamp preservation through branching (#2691 by @w-winter)

Fixed

• Fixed startup resource loading to reuse the initial ResourceLoader for the first runtime, so extensions are not loaded twice before session startup and session_start handlers still fire for singleton-style extensions (#2766)
• Fixed retry settlement so retried agent runs wait for the full retry cycle to complete before declaring idle, preventing stale state after transient errors
• Fixed theme export colors to resolve theme variables the same way as colors, so /export HTML backgrounds now honor entries like pageBg: "base" instead of requiring inline hex values (#2707)
• Fixed Bedrock throttling errors being misidentified as context overflow, causing unnecessary compaction instead of retry (#2699 by @xu0o0)
• Added tool streaming support for newer Z.ai models (#2732 by @kaofelix)