This release introduces session trees for in-place branching, major API changes to hooks and custom tools, and structured compaction with file tracking.

Session Tree

Sessions now use a tree structure with id/parentId fields. This enables in-place branching: navigate to any previous point with /tree, continue from there, and switch between branches while preserving all history in a single file.

Existing sessions are automatically migrated (v1 → v2) on first load. No manual action required.

New entry types: BranchSummaryEntry (context from abandoned branches), CustomEntry (hook state), CustomMessageEntry (hook-injected messages), LabelEntry (bookmarks).

See docs/session.md for the file format and SessionManager API.

Hooks Migration

The hooks API has been restructured with more granular events and better session access.

Type renames:

• HookEventContext → HookContext
• HookCommandContext is now a new interface extending HookContext with session control methods

Event changes:

• The monolithic session event is now split into granular events: session_start, session_before_switch, session_switch, session_before_branch, session_branch, session_before_compact, session_compact, session_shutdown
• session_before_switch and session_switch events now include reason: "new" | "resume" to distinguish between /new and /resume
• New session_before_tree and session_tree events for /tree navigation (hook can provide custom branch summary)
• New before_agent_start event: inject messages before the agent loop starts
• New context event: modify messages non-destructively before each LLM call
• Session entries are no longer passed in events. Use ctx.sessionManager.getEntries() or ctx.sessionManager.getBranch() instead

API changes:

• pi.send(text, attachments?) → pi.sendMessage(message, triggerTurn?) (creates CustomMessageEntry)
• New pi.appendEntry(customType, data?) for hook state persistence (not in LLM context)
• New pi.registerCommand(name, options) for custom slash commands (handler receives HookCommandContext)
• New pi.registerMessageRenderer(customType, renderer) for custom TUI rendering
• New ctx.isIdle(), ctx.abort(), ctx.hasQueuedMessages() for agent state (available in all events)
• New ctx.ui.editor(title, prefill?) for multi-line text editing with Ctrl+G external editor support
• New ctx.ui.custom(component) for full TUI component rendering with keyboard focus
• New ctx.ui.setStatus(key, text) for persistent status text in footer (multiple hooks can set their own)
• New ctx.ui.theme getter for styling text with theme colors
• ctx.exec() moved to pi.exec()
• ctx.sessionFile → ctx.sessionManager.getSessionFile()
• New ctx.modelRegistry and ctx.model for API key resolution

HookCommandContext (slash commands only):

• ctx.waitForIdle() - wait for agent to finish streaming
• ctx.newSession(options?) - create new sessions with optional setup callback
• ctx.branch(entryId) - branch from a specific entry
• ctx.navigateTree(targetId, options?) - navigate the session tree

These methods are only on HookCommandContext (not HookContext) because they can deadlock if called from event handlers that run inside the agent loop.

Removed:

• hookTimeout setting (hooks no longer have timeouts; use Ctrl+C to abort)
• resolveApiKey parameter (use ctx.modelRegistry.getApiKey(model))

See docs/hooks.md and examples/hooks/ for the current API.

Custom Tools Migration

The custom tools API has been restructured to mirror the hooks pattern with a context object.

Type renames:

• CustomAgentTool → CustomTool
• ToolAPI → CustomToolAPI
• ToolContext → CustomToolContext
• ToolSessionEvent → CustomToolSessionEvent

Execute signature changed:

// Before (v0.30.2)
execute(toolCallId, params, signal, onUpdate)

// After
execute(toolCallId, params, onUpdate, ctx, signal?)

The new ctx: CustomToolContext provides sessionManager, modelRegistry, model, and agent state methods:

• ctx.isIdle() - check if agent is streaming
• ctx.hasQueuedMessages() - check if user has queued messages (skip interactive prompts)
• ctx.abort() - abort current operation (fire-and-forget)

Session event changes:

• CustomToolSessionEvent now only has reason and previousSessionFile
• Session entries are no longer in the event. Use ctx.sessionManager.getBranch() or ctx.sessionManager.getEntries() to reconstruct state
• Reasons: "start" | "switch" | "branch" | "tree" | "shutdown" (no separate "new" reason; /new triggers "switch")
• dispose() method removed. Use onSession with reason: "shutdown" for cleanup

See docs/custom-tools.md and examples/custom-tools/ for the current API.

SDK Migration

Type changes:

• CustomAgentTool → CustomTool
• AppMessage → AgentMessage
• sessionFile returns string | undefined (was string | null)
• model returns Model | undefined (was Model | null)
• Attachment type removed. Use ImageContent from @mariozechner/pi-ai instead. Add images directly to message content arrays.

AgentSession API:

• branch(entryIndex: number) → branch(entryId: string)
• getUserMessagesForBranching() returns { entryId, text } instead of { entryIndex, text }
• reset() → newSession(options?) where options has optional parentSession for lineage tracking
• newSession() and switchSession() now return Promise<boolean> (false if cancelled by hook)
• New navigateTree(targetId, options?) for in-place tree navigation

Hook integration:

• New sendHookMessage(message, triggerTurn?) for hook message injection

SessionManager API:

• Method renames: saveXXX() → appendXXX() (e.g., appendMessage, appendCompaction)
• branchInPlace() → branch()
• reset() → newSession(options?) with optional parentSession for lineage tracking
• createBranchedSessionFromEntries(entries, index) → createBranchedSession(leafId)
• SessionHeader.branchedFrom → SessionHeader.parentSession
• saveCompaction(entry) → appendCompaction(summary, firstKeptEntryId, tokensBefore, details?)
• getEntries() now excludes the session header (use getHeader() separately)
• getSessionFile() returns string | undefined (undefined for in-memory sessions)
• New tree methods: getTree(), getBranch(), getLeafId(), getLeafEntry(), getEntry(), getChildren(), getLabel()
• New append methods: appendCustomEntry(), appendCustomMessageEntry(), appendLabelChange()
• New branch methods: branch(entryId), branchWithSummary()

ModelRegistry (new):

ModelRegistry is a new class that manages model discovery and API key resolution. It combines built-in models with custom models from models.json and resolves API keys via AuthStorage.

import { discoverAuthStorage, discoverModels } from "@mariozechner/pi-coding-agent";

const authStorage = discoverAuthStorage();  // ~/.pi/agent/auth.json
const modelRegistry = discoverModels(authStorage);  // + ~/.pi/agent/models.json

// Get all models (built-in + custom)
const allModels = modelRegistry.getAll();

// Get only models with valid API keys
const available = await modelRegistry.getAvailable();

// Find specific model
const model = modelRegistry.find("anthropic", "claude-sonnet-4-20250514");

// Get API key for a model
const apiKey = await modelRegistry.getApiKey(model);

This replaces the old resolveApiKey callback pattern. Hooks and custom tools access it via ctx.modelRegistry.

Renamed exports:

• messageTransformer → convertToLlm
• SessionContext alias LoadedSession removed

See docs/sdk.md and examples/sdk/ for the current API.

RPC Migration

Session commands:

• reset command → new_session command with optional parentSession field

Branching commands:

• branch command: entryIndex → entryId
• get_branch_messages response: entryIndex → entryId

Type changes:

• Messages are now AgentMessage (was AppMessage)
• prompt command: attachments field replaced with images field using ImageContent format

Compaction events:

• auto_compaction_start now includes reason field ("threshold" or "overflow")
• auto_compaction_end now includes willRetry field
• compact response includes full CompactionResult (summary, firstKeptEntryId, tokensBefore, details)

See docs/rpc.md for the current protocol.

Structured Compaction

Compaction and branch summarization now use a structured output format:

• Clear sections: Goal, Progress, Key Information, File Operations
• File tracking: readFiles and modifiedFiles arrays in details, accumulated across compactions
• Conversations are serialized to text before summarization to prevent the model from "continuing" them

The before_compact and before_tree hook events allow custom compaction implementations. See docs/compaction.md.

Interactive Mode

/tree command:

• Navigate the full session tree in-place
• Search by typing, page with ←/→
• Filter modes (Ctrl+O): default → no-tools → user-only → labeled-only → all
• Press l to label entries as bookmarks
• Selecting a branch switches context and optionally injects a summary of the abandoned branch

Entry labels:

• Bookmark any entry via /tree → select → l
• Labels appear in tree view and persist as LabelEntry

Theme changes (breaking for custom themes):

Custom themes must add these new color tokens or they will fail to load:

• selectedBg: background for selected/highlighted items in tree selector and other components
• customMessageBg: background for hook-injected messages (CustomMessageEntry)
• customMessageText: text color for hook messages
• customMessageLabel: label color for hook messages (the [customType] prefix)

Total color count increased from 46 to 50. See docs/theme.md for the full color list and copy values from the built-in dark/light themes.

Settings:

• enabledModels: allowlist models in settings.json (same format as --models CLI)

Added

• ctx.ui.setStatus(key, text) for hooks to display persistent status text in the footer (#385 by @prateekmedia)
• ctx.ui.theme getter for styling status text and other output with theme colors
• /share command to upload session as a secret GitHub gist and get a shareable URL via shittycodingagent.ai (#380)
• HTML export now includes a tree visualization sidebar for navigating session branches (#375)
• HTML export supports keyboard shortcuts: Ctrl+T to toggle thinking blocks, Ctrl+O to toggle tool outputs
• HTML export supports theme-configurable background colors via optional export section in theme JSON (#387 by @mitsuhiko)
• HTML export syntax highlighting now uses theme colors and matches TUI rendering
• Snake game example hook: Demonstrates ui.custom(), registerCommand(), and session persistence. See examples/hooks/snake.ts.
• thinkingText theme token: Configurable color for thinking block text. (#366 by @paulbettner)

Changed

• Entry IDs: Session entries now use short 8-character hex IDs instead of full UUIDs
• API key priority: ANTHROPIC_OAUTH_TOKEN now takes precedence over ANTHROPIC_API_KEY
• HTML export template split into separate files (template.html, template.css, template.js) for easier maintenance

Fixed

• HTML export now properly sanitizes user messages containing HTML tags like <style> that could break DOM rendering
• Crash when displaying bash output containing Unicode format characters like U+0600-U+0604 (#372 by @HACKE-RC)
• Footer shows full session stats: Token usage and cost now include all messages, not just those after compaction. (#322)
• Status messages spam chat log: Rapidly changing settings (e.g., thinking level via Shift+Tab) would add multiple status lines. Sequential status updates now coalesce into a single line. (#365 by @paulbettner)
• Toggling thinking blocks during streaming shows nothing: Pressing Ctrl+T while streaming would hide the current message until streaming completed.
• Resuming session resets thinking level to off: Initial model and thinking level were not saved to session file, causing --resume/--continue to default to off. (#342 by @aliou)
• Hook tool_result event ignores errors from custom tools: The tool_result hook event was never emitted when tools threw errors, and always had isError: false for successful executions. Now emits the event with correct isError value in both success and error cases. (#374 by @nicobailon)
• Edit tool fails on Windows due to CRLF line endings: Files with CRLF line endings now match correctly when LLMs send LF-only text. Line endings are normalized before matching and restored to original style on write. (#355 by @Pratham-Dubey)
• Edit tool fails on files with UTF-8 BOM: Files with UTF-8 BOM marker could cause "text not found" errors since the LLM doesn't include the invisible BOM character. BOM is now stripped before matching and restored on write. (#394 by @prathamdby)
• Use bash instead of sh on Unix: Fixed shell commands using /bin/sh instead of /bin/bash on Unix systems. (#328 by @dnouri)
• OAuth login URL clickable: Made OAuth login URLs clickable in terminal. (#349 by @Cursivez)
• Improved error messages: Better error messages when apiKey or model are missing. (#346 by @ronyrus)
• Session file validation: findMostRecentSession() now validates session headers before returning, preventing non-session JSONL files from being loaded
• Compaction error handling: generateSummary() and generateTurnPrefixSummary() now throw on LLM errors instead of returning empty strings
• Compaction with branched sessions: Fixed compaction incorrectly including entries from abandoned branches, causing token overflow errors. Compaction now uses sessionManager.getPath() to work only on the current branch path, eliminating 80+ lines of duplicate entry collection logic between prepareCompaction() and compact()
• enabledModels glob patterns: --models and enabledModels now support glob patterns like github-copilot/* or *sonnet*. Previously, patterns were only matched literally or via substring search. (#337)