feat(agent): add initial harness foundation

packages/agent/src/harness/messages.ts

@@ -0,0 +1,164 @@
+import type { ImageContent, Message, TextContent } from "@mariozechner/pi-ai";
+import type { AgentMessage } from "../types.js";
+
+export const COMPACTION_SUMMARY_PREFIX = `The conversation history before this point was compacted into the following summary:
+
+<summary>
+`;
+
+export const COMPACTION_SUMMARY_SUFFIX = `
+</summary>`;
+
+export const BRANCH_SUMMARY_PREFIX = `The following is a summary of a branch that this conversation came back from:
+
+<summary>
+`;
+
+export const BRANCH_SUMMARY_SUFFIX = `</summary>`;
+
+export interface BashExecutionMessage {
+	role: "bashExecution";
+	command: string;
+	output: string;
+	exitCode: number | undefined;
+	cancelled: boolean;
+	truncated: boolean;
+	fullOutputPath?: string;
+	timestamp: number;
+	excludeFromContext?: boolean;
+}
+
+export interface CustomMessage<T = unknown> {
+	role: "custom";
+	customType: string;
+	content: string | (TextContent | ImageContent)[];
+	display: boolean;
+	details?: T;
+	timestamp: number;
+}
+
+export interface BranchSummaryMessage {
+	role: "branchSummary";
+	summary: string;
+	fromId: string;
+	timestamp: number;
+}
+
+export interface CompactionSummaryMessage {
+	role: "compactionSummary";
+	summary: string;
+	tokensBefore: number;
+	timestamp: number;
+}
+
+declare module "../types.js" {
+	interface CustomAgentMessages {
+		bashExecution: BashExecutionMessage;
+		custom: CustomMessage;
+		branchSummary: BranchSummaryMessage;
+		compactionSummary: CompactionSummaryMessage;
+	}
+}
+
+export function bashExecutionToText(msg: BashExecutionMessage): string {
+	let text = `Ran \`${msg.command}\`\n`;
+	if (msg.output) {
+		text += `\`\`\`\n${msg.output}\n\`\`\``;
+	} else {
+		text += "(no output)";
+	}
+	if (msg.cancelled) {
+		text += "\n\n(command cancelled)";
+	} else if (msg.exitCode !== null && msg.exitCode !== undefined && msg.exitCode !== 0) {
+		text += `\n\nCommand exited with code ${msg.exitCode}`;
+	}
+	if (msg.truncated && msg.fullOutputPath) {
+		text += `\n\n[Output truncated. Full output: ${msg.fullOutputPath}]`;
+	}
+	return text;
+}
+
+export function createBranchSummaryMessage(summary: string, fromId: string, timestamp: string): BranchSummaryMessage {
+	return {
+		role: "branchSummary",
+		summary,
+		fromId,
+		timestamp: new Date(timestamp).getTime(),
+	};
+}
+
+export function createCompactionSummaryMessage(
+	summary: string,
+	tokensBefore: number,
+	timestamp: string,
+): CompactionSummaryMessage {
+	return {
+		role: "compactionSummary",
+		summary,
+		tokensBefore,
+		timestamp: new Date(timestamp).getTime(),
+	};
+}
+
+export function createCustomMessage(
+	customType: string,
+	content: string | (TextContent | ImageContent)[],
+	display: boolean,
+	details: unknown | undefined,
+	timestamp: string,
+): CustomMessage {
+	return {
+		role: "custom",
+		customType,
+		content,
+		display,
+		details,
+		timestamp: new Date(timestamp).getTime(),
+	};
+}
+
+export function convertToLlm(messages: AgentMessage[]): Message[] {
+	return messages
+		.map((m): Message | undefined => {
+			switch (m.role) {
+				case "bashExecution":
+					if (m.excludeFromContext) {
+						return undefined;
+					}
+					return {
+						role: "user",
+						content: [{ type: "text", text: bashExecutionToText(m) }],
+						timestamp: m.timestamp,
+					};
+				case "custom": {
+					const content = typeof m.content === "string" ? [{ type: "text" as const, text: m.content }] : m.content;
+					return {
+						role: "user",
+						content,
+						timestamp: m.timestamp,
+					};
+				}
+				case "branchSummary":
+					return {
+						role: "user",
+						content: [{ type: "text" as const, text: BRANCH_SUMMARY_PREFIX + m.summary + BRANCH_SUMMARY_SUFFIX }],
+						timestamp: m.timestamp,
+					};
+				case "compactionSummary":
+					return {
+						role: "user",
+						content: [
+							{ type: "text" as const, text: COMPACTION_SUMMARY_PREFIX + m.summary + COMPACTION_SUMMARY_SUFFIX },
+						],
+						timestamp: m.timestamp,
+					};
+				case "user":
+				case "assistant":
+				case "toolResult":
+					return m;
+				default:
+					return undefined;
+			}
+		})
+		.filter((m): m is Message => m !== undefined);
+}