Cleanup: unify HookMessage naming and simplify SessionContext

- Rename HookAppMessage to HookMessage, isHookAppMessage to isHookMessage
- Remove entries array from SessionContext (use isHookMessage type guard instead)
- HookMessage.content now accepts string directly (not just array)
- Fix streamMessage type in AgentState (AppMessage, not Message)
- Rename CustomMessageComponent to HookMessageComponent
- Fix test hook to use pi.sendMessage

packages/coding-agent/CHANGELOG.md

@@ -56,8 +56,8 @@
 - **Entry labels**: New `getLabel(id)` and `appendLabelChange(targetId, label)` methods for labeling entries. Labels are included in `SessionTreeNode` for UI/export.
 - **TUI**: `CustomMessageEntry` renders with purple styling (customMessageBg, customMessageText, customMessageLabel theme colors). Entries with `display: false` are hidden.
 - **AgentSession**: New `sendHookMessage(message, triggerTurn?)` method for hooks to inject messages. Handles queuing during streaming, direct append when idle, and optional turn triggering.
-- **HookAppMessage**: New message type with `role: "hookMessage"` for hook-injected messages in agent events. Use `isHookAppMessage(msg)` type guard to identify them. These are converted to user messages for LLM context via `messageTransformer`.
-- **Agent.prompt()**: Now accepts `AppMessage` directly (in addition to `string, attachments?`) for custom message types like `HookAppMessage`.
+- **HookMessage**: New message type with `role: "hookMessage"` for hook-injected messages in agent events. Use `isHookMessage(msg)` type guard to identify them. These are converted to user messages for LLM context via `messageTransformer`.
+- **Agent.prompt()**: Now accepts `AppMessage` directly (in addition to `string, attachments?`) for custom message types like `HookMessage`.
 
 ### Fixed
 

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

@@ -219,7 +219,7 @@ For arbitrary hook UI with keyboard focus:
 ```typescript
 interface HookUIContext {
   // ... existing: select, confirm, input, notify
-  
+
   /** Show custom component with keyboard focus. Call done() when finished. */
   custom(component: Component, done: () => void): void;
 }
@@ -325,7 +325,7 @@ Review and update all docs:
   - Updated event signatures (`SessionEventBase`, `before_compact`, etc.)
 - [ ] `docs/hooks-v2.md` - Review/merge or remove if obsolete
 - [ ] `docs/sdk.md` - Update for:
-  - `HookAppMessage` and `isHookAppMessage()` 
+  - `HookMessage` and `isHookMessage()`
   - `Agent.prompt(AppMessage)` overload
   - Session v2 tree structure
   - SessionManager API changes

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

@@ -14,7 +14,7 @@
  */
 
 import type { Agent, AgentEvent, AgentState, AppMessage, Attachment, ThinkingLevel } from "@mariozechner/pi-agent-core";
-import type { AssistantMessage, ImageContent, Message, Model, TextContent } from "@mariozechner/pi-ai";
+import type { AssistantMessage, Message, Model, TextContent } from "@mariozechner/pi-ai";
 import { isContextOverflow, modelsAreEqual, supportsXhigh } from "@mariozechner/pi-ai";
 import { getAuthPath } from "../config.js";
 import { type BashResult, executeBash as executeBashCommand } from "./bash-executor.js";
@@ -29,13 +29,12 @@ import type { LoadedCustomTool, SessionEvent as ToolSessionEvent } from "./custo
 import { exportSessionToHtml } from "./export-html.js";
 import type {
 	HookCommandContext,
-	HookMessage,
 	HookRunner,
 	SessionEventResult,
 	TurnEndEvent,
 	TurnStartEvent,
 } from "./hooks/index.js";
-import { type BashExecutionMessage, type HookAppMessage, isHookAppMessage } from "./messages.js";
+import { type BashExecutionMessage, type HookMessage, isHookMessage } from "./messages.js";
 import type { ModelRegistry } from "./model-registry.js";
 import type { CompactionEntry, SessionManager } from "./session-manager.js";
 import type { SettingsManager, SkillsSettings } from "./settings-manager.js";
@@ -220,7 +219,7 @@ export class AgentSession {
 		// Handle session persistence
 		if (event.type === "message_end") {
 			// Check if this is a hook message (has _hookData marker)
-			if (isHookAppMessage(event.message)) {
+			if (isHookMessage(event.message)) {
 				// Persist as CustomMessageEntry
 				this.sessionManager.appendCustomMessageEntry(
 					event.message.customType,
@@ -557,21 +556,18 @@ export class AgentSession {
 	 * @param message Hook message with customType, content, display, details
 	 * @param triggerTurn If true and not streaming, triggers a new LLM turn
 	 */
-	async sendHookMessage<T = unknown>(message: HookMessage<T>, triggerTurn?: boolean): Promise<void> {
-		// Normalize content to array format for the AppMessage
-		const content: (TextContent | ImageContent)[] =
-			typeof message.content === "string" ? [{ type: "text", text: message.content }] : message.content;
-
-		// Create HookAppMessage with proper role for type-safe handling
-		const appMessage: HookAppMessage = {
-			role: "hookMessage",
+	async sendHookMessage<T = unknown>(
+		message: Pick<HookMessage<T>, "customType" | "content" | "display" | "details">,
+		triggerTurn?: boolean,
+	): Promise<void> {
+		const appMessage = {
+			role: "hookMessage" as const,
 			customType: message.customType,
-			content,
+			content: message.content,
 			display: message.display,
 			details: message.details,
 			timestamp: Date.now(),
-		};
-
+		} satisfies HookMessage<T>;
 		if (this.isStreaming) {
 			// Queue for processing by agent loop
 			await this.agent.queueMessage(appMessage);

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

@@ -27,7 +27,6 @@ export type {
 	HookEvent,
 	HookEventContext,
 	HookFactory,
-	HookMessage,
 	HookMessageRenderer,
 	HookMessageRenderOptions,
 	HookUIContext,

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

@@ -9,15 +9,9 @@ import * as path from "node:path";
 import { fileURLToPath } from "node:url";
 import { createJiti } from "jiti";
 import { getAgentDir } from "../../config.js";
+import type { HookMessage } from "../messages.js";
 import { execCommand } from "./runner.js";
-import type {
-	ExecOptions,
-	HookAPI,
-	HookFactory,
-	HookMessage,
-	HookMessageRenderer,
-	RegisteredCommand,
-} from "./types.js";
+import type { ExecOptions, HookAPI, HookFactory, HookMessageRenderer, RegisteredCommand } from "./types.js";
 
 // Create require function to resolve module paths at runtime
 const require = createRequire(import.meta.url);
@@ -56,7 +50,10 @@ type HandlerFn = (...args: unknown[]) => Promise<unknown>;
 /**
  * Send message handler type for pi.sendMessage().
  */
-export type SendMessageHandler = <T = unknown>(message: HookMessage<T>, triggerTurn?: boolean) => void;
+export type SendMessageHandler = <T = unknown>(
+	message: Pick<HookMessage<T>, "customType" | "content" | "display" | "details">,
+	triggerTurn?: boolean,
+) => void;
 
 /**
  * Append entry handler type for pi.appendEntry().

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

@@ -11,8 +11,9 @@ import type { Component } from "@mariozechner/pi-tui";
 import type { Theme } from "../../modes/interactive/theme/theme.js";
 import type { CompactionPreparation, CompactionResult } from "../compaction.js";
 import type { ExecOptions, ExecResult } from "../exec.js";
+import type { HookMessage } from "../messages.js";
 import type { ModelRegistry } from "../model-registry.js";
-import type { CompactionEntry, CustomMessageEntry, SessionManager } from "../session-manager.js";
+import type { CompactionEntry, SessionManager } from "../session-manager.js";
 import type { EditToolDetails } from "../tools/edit.js";
 import type {
 	BashToolDetails,
@@ -380,14 +381,6 @@ export interface SessionEventResult {
  */
 export type HookHandler<E, R = void> = (event: E, ctx: HookEventContext) => Promise<R>;
 
-/**
- * Options passed to custom message renderers.
- */
-/**
- * Message type for hooks to send. Creates CustomMessageEntry in the session.
- */
-export type HookMessage<T = unknown> = Pick<CustomMessageEntry<T>, "customType" | "content" | "display" | "details">;
-
 export interface HookMessageRenderOptions {
 	/** Whether the view is expanded */
 	expanded: boolean;
@@ -463,7 +456,10 @@ export interface HookAPI {
 	 * @param triggerTurn - If true and agent is idle, triggers a new LLM turn. Default: false.
 	 *                      If agent is streaming, message is queued and triggerTurn is ignored.
 	 */
-	sendMessage<T = unknown>(message: HookMessage<T>, triggerTurn?: boolean): void;
+	sendMessage<T = unknown>(
+		message: Pick<HookMessage<T>, "customType" | "content" | "display" | "details">,
+		triggerTurn?: boolean,
+	): void;
 
 	/**
 	 * Append a custom entry to the session for hook state persistence.

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

@@ -32,10 +32,10 @@ import type { ImageContent, TextContent } from "@mariozechner/pi-ai";
  * Message type for hook-injected messages via sendMessage().
  * These are custom messages that hooks can inject into the conversation.
  */
-export interface HookAppMessage<T = unknown> {
+export interface HookMessage<T = unknown> {
 	role: "hookMessage";
 	customType: string;
-	content: (TextContent | ImageContent)[];
+	content: string | (TextContent | ImageContent)[];
 	display: boolean;
 	details?: T;
 	timestamp: number;
@@ -45,7 +45,7 @@ export interface HookAppMessage<T = unknown> {
 declare module "@mariozechner/pi-agent-core" {
 	interface CustomMessages {
 		bashExecution: BashExecutionMessage;
-		hookMessage: HookAppMessage;
+		hookMessage: HookMessage;
 	}
 }
 
@@ -63,8 +63,8 @@ export function isBashExecutionMessage(msg: AppMessage | Message): msg is BashEx
 /**
  * Type guard for HookAppMessage.
  */
-export function isHookAppMessage(msg: AppMessage | Message): msg is HookAppMessage {
-	return (msg as HookAppMessage).role === "hookMessage";
+export function isHookMessage(msg: AppMessage | Message): msg is HookMessage {
+	return (msg as HookMessage).role === "hookMessage";
 }
 
 // ============================================================================
@@ -114,7 +114,7 @@ export function messageTransformer(messages: AppMessage[]): Message[] {
 					timestamp: m.timestamp,
 				};
 			}
-			if (isHookAppMessage(m)) {
+			if (isHookMessage(m)) {
 				// Convert hook message to user message for LLM
 				return {
 					role: "user",

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

@@ -131,8 +131,6 @@ export interface SessionTreeNode {
 
 export interface SessionContext {
 	messages: AppMessage[];
-	/** Entries in the current path (root to leaf). Use to identify custom_message entries for rendering. */
-	entries: SessionEntry[];
 	thinkingLevel: string;
 	model: { provider: string; modelId: string } | null;
 }
@@ -292,7 +290,7 @@ export function buildSessionContext(
 	}
 
 	if (!leaf) {
-		return { messages: [], entries: [], thinkingLevel: "off", model: null };
+		return { messages: [], thinkingLevel: "off", model: null };
 	}
 
 	// Walk from leaf to root, collecting path
@@ -326,12 +324,10 @@ export function buildSessionContext(
 	// 2. Emit kept messages (from firstKeptEntryId up to compaction)
 	// 3. Emit messages after compaction
 	const messages: AppMessage[] = [];
-	const contextEntries: SessionEntry[] = [];
 
 	if (compaction) {
 		// Emit summary first
 		messages.push(createSummaryMessage(compaction.summary, compaction.timestamp));
-		contextEntries.push(compaction);
 
 		// Find compaction index in path
 		const compactionIdx = path.findIndex((e) => e.type === "compaction" && e.id === compaction.id);
@@ -346,13 +342,10 @@ export function buildSessionContext(
 			if (foundFirstKept) {
 				if (entry.type === "message") {
 					messages.push(entry.message);
-					contextEntries.push(entry);
 				} else if (entry.type === "custom_message") {
 					messages.push(createCustomMessage(entry));
-					contextEntries.push(entry);
 				} else if (entry.type === "branch_summary") {
 					messages.push(createSummaryMessage(entry.summary, entry.timestamp));
-					contextEntries.push(entry);
 				}
 			}
 		}
@@ -362,13 +355,10 @@ export function buildSessionContext(
 			const entry = path[i];
 			if (entry.type === "message") {
 				messages.push(entry.message);
-				contextEntries.push(entry);
 			} else if (entry.type === "custom_message") {
 				messages.push(createCustomMessage(entry));
-				contextEntries.push(entry);
 			} else if (entry.type === "branch_summary") {
 				messages.push(createSummaryMessage(entry.summary, entry.timestamp));
-				contextEntries.push(entry);
 			}
 		}
 	} else {
@@ -376,18 +366,15 @@ export function buildSessionContext(
 		for (const entry of path) {
 			if (entry.type === "message") {
 				messages.push(entry.message);
-				contextEntries.push(entry);
 			} else if (entry.type === "custom_message") {
 				messages.push(createCustomMessage(entry));
-				contextEntries.push(entry);
 			} else if (entry.type === "branch_summary") {
 				messages.push(createSummaryMessage(entry.summary, entry.timestamp));
-				contextEntries.push(entry);
 			}
 		}
 	}
 
-	return { messages, entries: contextEntries, thinkingLevel, model };
+	return { messages, thinkingLevel, model };
 }
 
 /**

packages/coding-agent/src/modes/interactive/components/hook-message.ts

@@ -1,22 +1,22 @@
 import type { TextContent } from "@mariozechner/pi-ai";
 import { Box, Container, Markdown, Spacer, Text } from "@mariozechner/pi-tui";
-import type { HookMessage, HookMessageRenderer } from "../../../core/hooks/types.js";
-import type { CustomMessageEntry } from "../../../core/session-manager.js";
+import type { HookMessage } from "packages/coding-agent/src/core/messages.js";
+import type { HookMessageRenderer } from "../../../core/hooks/types.js";
 import { getMarkdownTheme, theme } from "../theme/theme.js";
 
 /**
  * Component that renders a custom message entry from hooks.
  * Uses distinct styling to differentiate from user messages.
  */
-export class CustomMessageComponent extends Container {
-	private entry: CustomMessageEntry;
+export class HookMessageComponent extends Container {
+	private message: HookMessage<unknown>;
 	private customRenderer?: HookMessageRenderer;
 	private box: Box;
 	private _expanded = false;
 
-	constructor(entry: CustomMessageEntry, customRenderer?: HookMessageRenderer) {
+	constructor(message: HookMessage<unknown>, customRenderer?: HookMessageRenderer) {
 		super();
-		this.entry = entry;
+		this.message = message;
 		this.customRenderer = customRenderer;
 
 		this.addChild(new Spacer(1));
@@ -38,18 +38,10 @@ export class CustomMessageComponent extends Container {
 	private rebuild(): void {
 		this.box.clear();
 
-		// Convert entry to HookMessage for renderer
-		const message: HookMessage = {
-			customType: this.entry.customType,
-			content: this.entry.content,
-			display: this.entry.display,
-			details: this.entry.details,
-		};
-
 		// Try custom renderer first
 		if (this.customRenderer) {
 			try {
-				const component = this.customRenderer(message, { expanded: this._expanded }, theme);
+				const component = this.customRenderer(this.message, { expanded: this._expanded }, theme);
 				if (component) {
 					this.box.addChild(component);
 					return;
@@ -60,16 +52,16 @@ export class CustomMessageComponent extends Container {
 		}
 
 		// Default rendering: label + content
-		const label = theme.fg("customMessageLabel", `\x1b[1m[${this.entry.customType}]\x1b[22m`);
+		const label = theme.fg("customMessageLabel", `\x1b[1m[${this.message.customType}]\x1b[22m`);
 		this.box.addChild(new Text(label, 0, 0));
 		this.box.addChild(new Spacer(1));
 
 		// Extract text content
 		let text: string;
-		if (typeof this.entry.content === "string") {
-			text = this.entry.content;
+		if (typeof this.message.content === "string") {
+			text = this.message.content;
 		} else {
-			text = this.entry.content
+			text = this.message.content
 				.filter((c): c is TextContent => c.type === "text")
 				.map((c) => c.text)
 				.join("\n");

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -28,7 +28,7 @@ import { APP_NAME, getAuthPath, getDebugLogPath } from "../../config.js";
 import type { AgentSession, AgentSessionEvent } from "../../core/agent-session.js";
 import type { LoadedCustomTool, SessionEvent as ToolSessionEvent } from "../../core/custom-tools/index.js";
 import type { HookUIContext } from "../../core/hooks/index.js";
-import { isBashExecutionMessage, isHookAppMessage } from "../../core/messages.js";
+import { isBashExecutionMessage, isHookMessage } from "../../core/messages.js";
 import {
 	getLatestCompactionEntry,
 	type SessionContext,
@@ -46,10 +46,10 @@ import { AssistantMessageComponent } from "./components/assistant-message.js";
 import { BashExecutionComponent } from "./components/bash-execution.js";
 import { CompactionComponent } from "./components/compaction.js";
 import { CustomEditor } from "./components/custom-editor.js";
-import { CustomMessageComponent } from "./components/custom-message.js";
 import { DynamicBorder } from "./components/dynamic-border.js";
 import { FooterComponent } from "./components/footer.js";
 import { HookInputComponent } from "./components/hook-input.js";
+import { HookMessageComponent } from "./components/hook-message.js";
 import { HookSelectorComponent } from "./components/hook-selector.js";
 import { ModelSelectorComponent } from "./components/model-selector.js";
 import { OAuthSelectorComponent } from "./components/oauth-selector.js";
@@ -817,7 +817,7 @@ export class InteractiveMode {
 				break;
 
 			case "message_start":
-				if (isHookAppMessage(event.message)) {
+				if (isHookMessage(event.message)) {
 					this.addMessageToChat(event.message);
 					this.ui.requestRender();
 				} else if (event.message.role === "user") {
@@ -1051,7 +1051,7 @@ export class InteractiveMode {
 		this.ui.requestRender();
 	}
 
-	private addMessageToChat(message: Message | AppMessage): void {
+	private addMessageToChat(message: AppMessage): void {
 		if (isBashExecutionMessage(message)) {
 			const component = new BashExecutionComponent(message.command, this.ui);
 			if (message.output) {
@@ -1067,20 +1067,11 @@ export class InteractiveMode {
 			return;
 		}
 
-		if (isHookAppMessage(message)) {
+		if (isHookMessage(message)) {
 			// Render as custom message if display is true
 			if (message.display) {
-				const entry = {
-					type: "custom_message" as const,
-					customType: message.customType,
-					content: message.content,
-					display: true,
-					id: "",
-					parentId: null,
-					timestamp: new Date().toISOString(),
-				};
 				const renderer = this.session.hookRunner?.getMessageRenderer(message.customType);
-				this.chatContainer.addChild(new CustomMessageComponent(entry, renderer));
+				this.chatContainer.addChild(new HookMessageComponent(message, renderer));
 			}
 		} else if (message.role === "user") {
 			const textContent = this.getUserMessageText(message);
@@ -1114,11 +1105,9 @@ export class InteractiveMode {
 		}
 
 		const compactionEntry = getLatestCompactionEntry(this.sessionManager.getEntries());
-		const entries = sessionContext.entries;
 
 		for (let i = 0; i < sessionContext.messages.length; i++) {
 			const message = sessionContext.messages[i];
-			const entry = entries?.[i];
 
 			if (isBashExecutionMessage(message)) {
 				this.addMessageToChat(message);
@@ -1126,10 +1115,10 @@ export class InteractiveMode {
 			}
 
 			// Check if this is a custom_message entry
-			if (entry?.type === "custom_message") {
-				if (entry.display) {
-					const renderer = this.session.hookRunner?.getMessageRenderer(entry.customType);
-					this.chatContainer.addChild(new CustomMessageComponent(entry, renderer));
+			if (isHookMessage(message)) {
+				if (message.display) {
+					const renderer = this.session.hookRunner?.getMessageRenderer(message.customType);
+					this.chatContainer.addChild(new HookMessageComponent(message, renderer));
 				}
 				continue;
 			}
@@ -1322,7 +1311,7 @@ export class InteractiveMode {
 				child.setExpanded(this.toolOutputExpanded);
 			} else if (child instanceof BashExecutionComponent) {
 				child.setExpanded(this.toolOutputExpanded);
-			} else if (child instanceof CustomMessageComponent) {
+			} else if (child instanceof HookMessageComponent) {
 				child.setExpanded(this.toolOutputExpanded);
 			}
 		}