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/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 };
 }
 
 /**