Update plan: HookCommandContext without sendMessage (use pi closure)

packages/coding-agent/docs/session-tree-plan.md

@@ -165,20 +165,20 @@ Calls `sessionManager.appendCustomEntry()` directly.
 **New: `registerCommand()` (types ✅, wiring TODO)**
 
 ```typescript
-interface CommandContext {
+interface HookCommandContext {
   args: string;                    // Everything after /commandname
   ui: HookUIContext;
   hasUI: boolean;
   cwd: string;
   sessionManager: SessionManager;
   modelRegistry: ModelRegistry;
-  sendMessage: HookAPI['sendMessage'];
   exec(command: string, args: string[], options?: ExecOptions): Promise<ExecResult>;
 }
+// Note: sendMessage not on context - handler captures `pi` in closure
 
 registerCommand(name: string, options: {
   description?: string;
-  handler: (ctx: CommandContext) => Promise<string | undefined>;
+  handler: (ctx: HookCommandContext) => Promise<void>;
 }): void;
 ```
 
@@ -188,7 +188,7 @@ Handler return:
 Wiring (all in AgentSession.prompt()):
 - [x] Add hook commands to autocomplete in interactive-mode
 - [x] `_tryExecuteHookCommand()` in AgentSession handles command execution
-- [x] Build CommandContext with ui (from hookRunner), exec, sessionManager, etc.
+- [x] Build HookCommandContext with ui (from hookRunner), exec, sessionManager, etc.
 - [x] If handler returns string, use as prompt text
 - [x] If handler returns undefined, return early (no LLM call)
 - [x] Works for all modes (interactive, RPC, print) via shared AgentSession
@@ -243,7 +243,7 @@ Review and update all docs:
   - New `pi.appendEntry()` for state persistence
   - New `pi.registerCommand()` for custom slash commands
   - New `pi.registerCustomMessageRenderer()` for custom TUI rendering
-  - `CommandContext` interface and handler patterns
+  - `HookCommandContext` interface and handler patterns
   - `HookMessage<T>` type
   - Updated event signatures (`SessionEventBase`, `before_compact`, etc.)
 - [ ] `docs/hooks-v2.md` - Review/merge or remove if obsolete

packages/coding-agent/src/core/agent-session.ts

@@ -28,9 +28,9 @@ import {
 import type { LoadedCustomTool, SessionEvent as ToolSessionEvent } from "./custom-tools/index.js";
 import { exportSessionToHtml } from "./export-html.js";
 import {
-	type CommandContext,
 	type ExecOptions,
 	execCommand,
+	type HookCommandContext,
 	type HookMessage,
 	type HookRunner,
 	type SessionEventResult,
@@ -512,18 +512,13 @@ export class AgentSession {
 
 		// Build command context
 		const cwd = process.cwd();
-		const ctx: CommandContext = {
+		const ctx: HookCommandContext = {
 			args,
 			ui: uiContext,
 			hasUI: this._hookRunner.getHasUI(),
 			cwd,
 			sessionManager: this.sessionManager,
 			modelRegistry: this._modelRegistry,
-			sendMessage: (message, triggerTurn) => {
-				this.sendHookMessage(message, triggerTurn).catch(() => {
-					// Error handling is done in sendHookMessage
-				});
-			},
 			exec: (cmd: string, cmdArgs: string[], options?: ExecOptions) => execCommand(cmd, cmdArgs, cwd, options),
 		};
 

packages/coding-agent/src/core/hooks/index.ts

@@ -1,18 +1,18 @@
+// biome-ignore assist/source/organizeImports: biome is not smart
 export {
-	type AppendEntryHandler,
 	discoverAndLoadHooks,
+	loadHooks,
+	type AppendEntryHandler,
 	type LoadedHook,
 	type LoadHooksResult,
-	loadHooks,
 	type SendMessageHandler,
 } from "./loader.js";
-export { execCommand, type HookErrorListener, HookRunner } from "./runner.js";
+export { execCommand, HookRunner, type HookErrorListener } from "./runner.js";
 export { wrapToolsWithHooks, wrapToolWithHooks } from "./tool-wrapper.js";
 export type {
 	AgentEndEvent,
 	AgentStartEvent,
 	BashToolResultEvent,
-	CommandContext,
 	CustomMessageRenderer,
 	CustomMessageRenderOptions,
 	CustomToolResultEvent,
@@ -22,6 +22,7 @@ export type {
 	FindToolResultEvent,
 	GrepToolResultEvent,
 	HookAPI,
+	HookCommandContext,
 	HookError,
 	HookEvent,
 	HookEventContext,

packages/coding-agent/src/core/hooks/types.ts

@@ -12,6 +12,7 @@ import type { Theme } from "../../modes/interactive/theme/theme.js";
 import type { CompactionPreparation, CompactionResult } from "../compaction.js";
 import type { ModelRegistry } from "../model-registry.js";
 import type { CompactionEntry, CustomMessageEntry, SessionManager } from "../session-manager.js";
+import type { EditToolDetails } from "../tools/edit.js";
 import type {
 	BashToolDetails,
 	FindToolDetails,
@@ -237,7 +238,7 @@ export interface ReadToolResultEvent extends ToolResultEventBase {
 /** Tool result event for edit tool */
 export interface EditToolResultEvent extends ToolResultEventBase {
 	toolName: "edit";
-	details: undefined;
+	details: EditToolDetails | undefined;
 }
 
 /** Tool result event for write tool */
@@ -394,9 +395,9 @@ export type CustomMessageRenderer<T = unknown> = (
 export type HookMessage<T = unknown> = Pick<CustomMessageEntry<T>, "customType" | "content" | "display" | "details">;
 
 /**
- * Context passed to command handlers.
+ * Context passed to hook command handlers.
  */
-export interface CommandContext {
+export interface HookCommandContext {
 	/** Arguments after the command name */
 	args: string;
 	/** UI methods for user interaction */
@@ -411,13 +412,6 @@ export interface CommandContext {
 	sessionManager: SessionManager;
 	/** Model registry for API keys */
 	modelRegistry: ModelRegistry;
-	/**
-	 * Send a custom message to the session.
-	 * If streaming, queued and appended after turn ends.
-	 * If idle and triggerTurn=true, appends and triggers a new turn.
-	 * If idle and triggerTurn=false (default), just appends.
-	 */
-	sendMessage<T = unknown>(message: HookMessage<T>, triggerTurn?: boolean): void;
 }
 
 /**
@@ -426,7 +420,7 @@ export interface CommandContext {
 export interface RegisteredCommand {
 	name: string;
 	description?: string;
-	handler: (ctx: CommandContext) => Promise<void>;
+	handler: (ctx: HookCommandContext) => Promise<void>;
 }
 
 /**

packages/coding-agent/src/core/tools/edit.ts

@@ -122,6 +122,11 @@ const editSchema = Type.Object({
 	newText: Type.String({ description: "New text to replace the old text with" }),
 });
 
+export interface EditToolDetails {
+	/** Unified diff of the changes made */
+	diff: string;
+}
+
 export function createEditTool(cwd: string): AgentTool<typeof editSchema> {
 	return {
 		name: "edit",