feat(ai): add shared contentText utility (#6840)

Co-authored-by: Armin Ronacher <armin.ronacher@active-4.com>

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

@@ -24,11 +24,11 @@ import type {
 	PrepareNextTurnContext,
 	ThinkingLevel,
 } from "@earendil-works/pi-agent-core";
+import { contentText } from "@earendil-works/pi-ai";
 import type {
 	AssistantMessage,
 	AuthResult,
 	ImageContent,
-	Message,
 	Model,
 	ProviderHeaders,
 	TextContent,
@@ -576,7 +576,7 @@ export class AgentSession {
 		// This ensures the UI sees the updated queue state
 		if (event.type === "message_start" && event.message.role === "user") {
 			this._overflowRecoveryAttempted = false;
-			const messageText = this._getUserMessageText(event.message);
+			const messageText = contentText(event.message.content, "");
 			if (messageText) {
 				// Check steering queue first
 				const steeringIndex = this._steeringMessages.indexOf(messageText);
@@ -659,15 +659,6 @@ export class AgentSession {
 		return false;
 	}
 
-	/** Extract text content from a message */
-	private _getUserMessageText(message: Message): string {
-		if (message.role !== "user") return "";
-		const content = message.content;
-		if (typeof content === "string") return content;
-		const textBlocks = content.filter((c) => c.type === "text");
-		return textBlocks.map((c) => (c as TextContent).text).join("");
-	}
-
 	/** Find the last assistant message in agent state (including aborted ones) */
 	private _findLastAssistantMessage(): AssistantMessage | undefined {
 		const messages = this.agent.state.messages;
@@ -2954,17 +2945,11 @@ export class AgentSession {
 			if (targetEntry.type === "message" && targetEntry.message.role === "user") {
 				// User message: leaf = parent (null if root), text goes to editor
 				newLeafId = targetEntry.parentId;
-				editorText = this._extractUserMessageText(targetEntry.message.content);
+				editorText = contentText(targetEntry.message.content, "");
 			} else if (targetEntry.type === "custom_message") {
 				// Custom message: leaf = parent (null if root), text goes to editor
 				newLeafId = targetEntry.parentId;
-				editorText =
-					typeof targetEntry.content === "string"
-						? targetEntry.content
-						: targetEntry.content
-								.filter((c): c is { type: "text"; text: string } => c.type === "text")
-								.map((c) => c.text)
-								.join("");
+				editorText = contentText(targetEntry.content, "");
 			} else {
 				// Non-user message: leaf = selected node
 				newLeafId = targetId;
@@ -3032,7 +3017,7 @@ export class AgentSession {
 			if (entry.type !== "message") continue;
 			if (entry.message.role !== "user") continue;
 
-			const text = this._extractUserMessageText(entry.message.content);
+			const text = contentText(entry.message.content, "");
 			if (text) {
 				result.push({ entryId: entry.id, text });
 			}
@@ -3041,17 +3026,6 @@ export class AgentSession {
 		return result;
 	}
 
-	private _extractUserMessageText(content: string | Array<{ type: string; text?: string }>): string {
-		if (typeof content === "string") return content;
-		if (Array.isArray(content)) {
-			return content
-				.filter((c): c is { type: "text"; text: string } => c.type === "text")
-				.map((c) => c.text)
-				.join("");
-		}
-		return "";
-	}
-
 	/**
 	 * Get session statistics. Aggregates over ALL session entries (including
 	 * history that was compacted away), so token/cost totals reflect what was

packages/coding-agent/src/core/compaction/branch-summarization.ts

@@ -6,6 +6,7 @@
  */
 
 import type { AgentMessage, StreamFn } from "@earendil-works/pi-agent-core";
+import { contentText } from "@earendil-works/pi-ai";
 import type { Model, SimpleStreamOptions } from "@earendil-works/pi-ai/compat";
 import { completeSimple } from "@earendil-works/pi-ai/compat";
 import {
@@ -351,10 +352,7 @@ export async function generateBranchSummary(
 		return { error: response.errorMessage || "Summarization failed" };
 	}
 
-	let summary = response.content
-		.filter((c): c is { type: "text"; text: string } => c.type === "text")
-		.map((c) => c.text)
-		.join("\n");
+	let summary = contentText(response.content);
 
 	// Prepend preamble to provide context about the branch summary
 	summary = BRANCH_SUMMARY_PREAMBLE + summary;

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

@@ -6,6 +6,7 @@
  */
 
 import type { AgentMessage, StreamFn, ThinkingLevel } from "@earendil-works/pi-agent-core";
+import { contentText } from "@earendil-works/pi-ai";
 import type { AssistantMessage, Context, Model, SimpleStreamOptions, Usage } from "@earendil-works/pi-ai/compat";
 import { completeSimple } from "@earendil-works/pi-ai/compat";
 import { convertToLlm } from "../messages.ts";
@@ -600,10 +601,7 @@ export async function generateSummary(
 		throw new Error(`Summarization failed: ${response.errorMessage || "Unknown error"}`);
 	}
 
-	const textContent = response.content
-		.filter((c): c is { type: "text"; text: string } => c.type === "text")
-		.map((c) => c.text)
-		.join("\n");
+	const textContent = contentText(response.content);
 
 	return textContent;
 }
@@ -865,8 +863,5 @@ async function generateTurnPrefixSummary(
 		throw new Error(`Turn prefix summarization failed: ${response.errorMessage || "Unknown error"}`);
 	}
 
-	return response.content
-		.filter((c): c is { type: "text"; text: string } => c.type === "text")
-		.map((c) => c.text)
-		.join("\n");
+	return contentText(response.content);
 }

packages/coding-agent/src/core/compaction/utils.ts

@@ -3,7 +3,7 @@
  */
 
 import type { AgentMessage } from "@earendil-works/pi-agent-core";
-import type { Message } from "@earendil-works/pi-ai";
+import { contentText, type Message } from "@earendil-works/pi-ai";
 
 // ============================================================================
 // File Operation Tracking
@@ -111,23 +111,14 @@ export function serializeConversation(messages: Message[]): string {
 
 	for (const msg of messages) {
 		if (msg.role === "user") {
-			const content =
-				typeof msg.content === "string"
-					? msg.content
-					: msg.content
-							.filter((c): c is { type: "text"; text: string } => c.type === "text")
-							.map((c) => c.text)
-							.join("");
+			const content = contentText(msg.content, "");
 			if (content) parts.push(`[User]: ${content}`);
 		} else if (msg.role === "assistant") {
-			const textParts: string[] = [];
 			const thinkingParts: string[] = [];
 			const toolCalls: string[] = [];
 
 			for (const block of msg.content) {
-				if (block.type === "text") {
-					textParts.push(block.text);
-				} else if (block.type === "thinking") {
+				if (block.type === "thinking") {
 					thinkingParts.push(block.thinking);
 				} else if (block.type === "toolCall") {
 					const args = block.arguments as Record<string, unknown>;
@@ -141,17 +132,14 @@ export function serializeConversation(messages: Message[]): string {
 			if (thinkingParts.length > 0) {
 				parts.push(`[Assistant thinking]: ${thinkingParts.join("\n")}`);
 			}
-			if (textParts.length > 0) {
-				parts.push(`[Assistant]: ${textParts.join("\n")}`);
+			if (msg.content.some((block) => block.type === "text")) {
+				parts.push(`[Assistant]: ${contentText(msg.content)}`);
 			}
 			if (toolCalls.length > 0) {
 				parts.push(`[Assistant tool calls]: ${toolCalls.join("; ")}`);
 			}
 		} else if (msg.role === "toolResult") {
-			const content = msg.content
-				.filter((c): c is { type: "text"; text: string } => c.type === "text")
-				.map((c) => c.text)
-				.join("");
+			const content = contentText(msg.content, "");
 			if (content) {
 				parts.push(`[Tool result]: ${truncateForSummary(content, TOOL_RESULT_MAX_CHARS)}`);
 			}