feat: integrate Pi backend and Pi Web

2026-10-03 02:59:35 +00:00 · 2026-07-30 19:37:53 +08:00
commit 7392ab9dd7
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+/**
+ * Handoff extension - transfer context to a new focused session
+ *
+ * Instead of compacting (which is lossy), handoff extracts what matters
+ * for your next task and creates a new session with a generated prompt.
+ *
+ * Usage:
+ *   /handoff now implement this for teams as well
+ *   /handoff execute phase one of the plan
+ *   /handoff check other places that need this fix
+ *
+ * The generated prompt appears as a draft in the editor for review/editing.
+ */
+
+import type { AgentMessage } from "@earendil-works/pi-agent-core";
+import { uuidv7 } from "@earendil-works/pi-ai";
+import { complete, type Message } from "@earendil-works/pi-ai/compat";
+import type { ExtensionAPI, SessionEntry } from "@earendil-works/pi-coding-agent";
+import { BorderedLoader, convertToLlm, serializeConversation } from "@earendil-works/pi-coding-agent";
+
+const SYSTEM_PROMPT = `You are a context transfer assistant. Given a conversation history and the user's goal for a new thread, generate a focused prompt that:
+
+1. Summarizes relevant context from the conversation (decisions made, approaches taken, key findings)
+2. Lists any relevant files that were discussed or modified
+3. Clearly states the next task based on the user's goal
+4. Is self-contained - the new thread should be able to proceed without the old conversation
+
+Format your response as a prompt the user can send to start the new thread. Be concise but include all necessary context. Do not include any preamble like "Here's the prompt" - just output the prompt itself.
+
+Example output format:
+## Context
+We've been working on X. Key decisions:
+- Decision 1
+- Decision 2
+
+Files involved:
+- path/to/file1.ts
+- path/to/file2.ts
+
+## Task
+[Clear description of what to do next based on user's goal]`;
+
+function entryToMessage(entry: SessionEntry): AgentMessage | undefined {
+	if (entry.type === "message") {
+		return entry.message;
+	}
+	if (entry.type === "compaction") {
+		return {
+			role: "compactionSummary",
+			summary: entry.summary,
+			tokensBefore: entry.tokensBefore,
+			timestamp: new Date(entry.timestamp).getTime(),
+		};
+	}
+	return undefined;
+}
+
+function getHandoffMessages(branch: SessionEntry[]): AgentMessage[] {
+	let compactionIndex = -1;
+	for (let i = branch.length - 1; i >= 0; i--) {
+		if (branch[i].type === "compaction") {
+			compactionIndex = i;
+			break;
+		}
+	}
+	if (compactionIndex < 0) {
+		return branch.map(entryToMessage).filter((message) => message !== undefined);
+	}
+
+	const compaction = branch[compactionIndex];
+	const firstKeptIndex =
+		compaction.type === "compaction" ? branch.findIndex((entry) => entry.id === compaction.firstKeptEntryId) : -1;
+	const compactedBranch = [
+		compaction,
+		...(firstKeptIndex >= 0 ? branch.slice(firstKeptIndex, compactionIndex) : []),
+		...branch.slice(compactionIndex + 1),
+	];
+	return compactedBranch.map(entryToMessage).filter((message) => message !== undefined);
+}
+
+export default function (pi: ExtensionAPI) {
+	pi.registerCommand("handoff", {
+		description: "Transfer context to a new focused session",
+		handler: async (args, ctx) => {
+			if (ctx.mode !== "tui") {
+				ctx.ui.notify("handoff requires interactive mode", "error");
+				return;
+			}
+
+			if (!ctx.model) {
+				ctx.ui.notify("No model selected", "error");
+				return;
+			}
+
+			const goal = args.trim();
+			if (!goal) {
+				ctx.ui.notify("Usage: /handoff <goal for new thread>", "error");
+				return;
+			}
+
+			// Gather conversation context from current branch. If the branch was compacted,
+			// include the compaction summary plus entries from firstKeptEntryId onward.
+			const messages = getHandoffMessages(ctx.sessionManager.getBranch());
+
+			if (messages.length === 0) {
+				ctx.ui.notify("No conversation to hand off", "error");
+				return;
+			}
+
+			// Convert to LLM format and serialize
+			const llmMessages = convertToLlm(messages);
+			const conversationText = serializeConversation(llmMessages);
+			const currentSessionFile = ctx.sessionManager.getSessionFile();
+
+			// Generate the handoff prompt with loader UI
+			const result = await ctx.ui.custom<string | null>((tui, theme, _kb, done) => {
+				const loader = new BorderedLoader(tui, theme, `Generating handoff prompt...`);
+				loader.onAbort = () => done(null);
+
+				const doGenerate = async () => {
+					const auth = await ctx.modelRegistry.getApiKeyAndHeaders(ctx.model!);
+					if (!auth.ok || !auth.apiKey) {
+						throw new Error(auth.ok ? `No API key for ${ctx.model!.provider}` : auth.error);
+					}
+
+					const userMessage: Message = {
+						role: "user",
+						content: [
+							{
+								type: "text",
+								text: `## Conversation History\n\n${conversationText}\n\n## User's Goal for New Thread\n\n${goal}`,
+							},
+						],
+						timestamp: Date.now(),
+					};
+
+					const response = await complete(
+						ctx.model!,
+						{ systemPrompt: SYSTEM_PROMPT, messages: [userMessage] },
+						{
+							apiKey: auth.apiKey,
+							headers: auth.headers,
+							env: auth.env,
+							signal: loader.signal,
+							cacheRetention: "none",
+							sessionId: uuidv7(),
+						},
+					);
+
+					if (response.stopReason === "aborted") {
+						return null;
+					}
+
+					return response.content
+						.filter((c): c is { type: "text"; text: string } => c.type === "text")
+						.map((c) => c.text)
+						.join("\n");
+				};
+
+				doGenerate()
+					.then(done)
+					.catch((err) => {
+						console.error("Handoff generation failed:", err);
+						done(null);
+					});
+
+				return loader;
+			});
+
+			if (result === null) {
+				ctx.ui.notify("Cancelled", "info");
+				return;
+			}
+
+			// Let user edit the generated prompt
+			const editedPrompt = await ctx.ui.editor("Edit handoff prompt", result);
+
+			if (editedPrompt === undefined) {
+				ctx.ui.notify("Cancelled", "info");
+				return;
+			}
+
+			// Create new session with parent tracking. Use the replacement-session
+			// context for post-switch UI work; the original ctx is stale after a
+			// successful session replacement.
+			const newSessionResult = await ctx.newSession({
+				parentSession: currentSessionFile,
+				withSession: async (replacementCtx) => {
+					replacementCtx.ui.setEditorText(editedPrompt);
+					replacementCtx.ui.notify("Handoff ready. Submit when ready.", "info");
+				},
+			});
+
+			if (newSessionResult.cancelled) {
+				ctx.ui.notify("New session cancelled", "info");
+			}
+		},
+	});
+}