Rework custom tools API with CustomToolContext

- CustomAgentTool renamed to CustomTool
- ToolAPI renamed to CustomToolAPI
- ToolContext renamed to CustomToolContext
- ToolSessionEvent renamed to CustomToolSessionEvent
- Added CustomToolContext parameter to execute() and onSession()
- CustomToolFactory now returns CustomTool<any, any> for type compatibility
- dispose() replaced with onSession({ reason: 'shutdown' })
- Added wrapCustomTool() to convert CustomTool to AgentTool
- Session exposes setToolUIContext() instead of leaking internals
- Fix ToolExecutionComponent to sync with toolOutputExpanded state
- Update all custom tool examples for new API

packages/coding-agent/examples/custom-tools/hello/index.ts

@@ -10,9 +10,10 @@ const factory: CustomToolFactory = (_pi) => ({
 	}),
 
 	async execute(_toolCallId, params) {
+		const { name } = params as { name: string };
 		return {
-			content: [{ type: "text", text: `Hello, ${params.name}!` }],
-			details: { greeted: params.name },
+			content: [{ type: "text", text: `Hello, ${name}!` }],
+			details: { greeted: name },
 		};
 	},
 });

packages/coding-agent/examples/custom-tools/question/index.ts

@@ -2,7 +2,7 @@
  * Question Tool - Let the LLM ask the user a question with options
  */
 
-import type { CustomAgentTool, CustomToolFactory } from "@mariozechner/pi-coding-agent";
+import type { CustomTool, CustomToolFactory } from "@mariozechner/pi-coding-agent";
 import { Text } from "@mariozechner/pi-tui";
 import { Type } from "@sinclair/typebox";
 
@@ -18,7 +18,7 @@ const QuestionParams = Type.Object({
 });
 
 const factory: CustomToolFactory = (pi) => {
-	const tool: CustomAgentTool<typeof QuestionParams, QuestionDetails> = {
+	const tool: CustomTool<typeof QuestionParams, QuestionDetails> = {
 		name: "question",
 		label: "Question",
 		description: "Ask the user a question and let them pick from options. Use when you need user input to proceed.",

packages/coding-agent/examples/custom-tools/subagent/index.ts

@@ -20,10 +20,10 @@ import type { AgentToolResult } from "@mariozechner/pi-agent-core";
 import type { Message } from "@mariozechner/pi-ai";
 import { StringEnum } from "@mariozechner/pi-ai";
 import {
-	type CustomAgentTool,
+	type CustomTool,
+	type CustomToolAPI,
 	type CustomToolFactory,
 	getMarkdownTheme,
-	type ToolAPI,
 } from "@mariozechner/pi-coding-agent";
 import { Container, Markdown, Spacer, Text } from "@mariozechner/pi-tui";
 import { Type } from "@sinclair/typebox";
@@ -224,7 +224,7 @@ function writePromptToTempFile(agentName: string, prompt: string): { dir: string
 type OnUpdateCallback = (partial: AgentToolResult<SubagentDetails>) => void;
 
 async function runSingleAgent(
-	pi: ToolAPI,
+	pi: CustomToolAPI,
 	agents: AgentConfig[],
 	agentName: string,
 	task: string,
@@ -411,7 +411,7 @@ const SubagentParams = Type.Object({
 });
 
 const factory: CustomToolFactory = (pi) => {
-	const tool: CustomAgentTool<typeof SubagentParams, SubagentDetails> = {
+	const tool: CustomTool<typeof SubagentParams, SubagentDetails> = {
 		name: "subagent",
 		label: "Subagent",
 		get description() {
@@ -433,7 +433,7 @@ const factory: CustomToolFactory = (pi) => {
 		},
 		parameters: SubagentParams,
 
-		async execute(_toolCallId, params, signal, onUpdate) {
+		async execute(_toolCallId, params, signal, onUpdate, _ctx) {
 			const agentScope: AgentScope = params.agentScope ?? "user";
 			const discovery = discoverAgents(pi.cwd, agentScope);
 			const agents = discovery.agents;

packages/coding-agent/examples/custom-tools/todo/index.ts

@@ -9,7 +9,12 @@
  */
 
 import { StringEnum } from "@mariozechner/pi-ai";
-import type { CustomAgentTool, CustomToolFactory, ToolSessionEvent } from "@mariozechner/pi-coding-agent";
+import type {
+	CustomTool,
+	CustomToolContext,
+	CustomToolFactory,
+	CustomToolSessionEvent,
+} from "@mariozechner/pi-coding-agent";
 import { Text } from "@mariozechner/pi-tui";
 import { Type } from "@sinclair/typebox";
 
@@ -43,11 +48,12 @@ const factory: CustomToolFactory = (_pi) => {
 	 * Reconstruct state from session entries.
 	 * Scans tool results for this tool and applies them in order.
 	 */
-	const reconstructState = (event: ToolSessionEvent) => {
+	const reconstructState = (_event: CustomToolSessionEvent, ctx: CustomToolContext) => {
 		todos = [];
 		nextId = 1;
 
-		for (const entry of event.entries) {
+		// Use getBranch() to get entries on the current branch
+		for (const entry of ctx.sessionManager.getBranch()) {
 			if (entry.type !== "message") continue;
 			const msg = entry.message;
 
@@ -63,7 +69,7 @@ const factory: CustomToolFactory = (_pi) => {
 		}
 	};
 
-	const tool: CustomAgentTool<typeof TodoParams, TodoDetails> = {
+	const tool: CustomTool<typeof TodoParams, TodoDetails> = {
 		name: "todo",
 		label: "Todo",
 		description: "Manage a todo list. Actions: list, add (text), toggle (id), clear",