Add session activity dock and auto naming

src/server/sessions/piSessionService.ts

@@ -15,6 +15,7 @@ import { BUILTIN_COMMANDS } from "./builtinCommands.js";
 import { SessionCommandService } from "./sessionCommandService.js";
 import { SessionArchiveStore } from "./sessionArchiveStore.js";
 import type { ActiveSession } from "./sessionRuntimeStore.js";
+import { generateShortSessionName } from "./sessionNameGenerator.js";
 
 function noop(): void {
   // Intentionally empty default unsubscribe callback.
@@ -129,6 +130,7 @@ export class PiSessionService {
   async prompt(sessionId: string, text: string, streamingBehavior?: "steer" | "followUp"): Promise<void> {
     await this.assertWritable(sessionId);
     const session = await this.getOrOpen(sessionId);
+    this.maybeGenerateSessionName(session, text);
     const behavior = session.isStreaming || session.isCompacting ? streamingBehavior ?? "followUp" : undefined;
     this.publishActivity(session, session.isCompacting ? "message queued during compaction" : behavior === "steer" ? "steering queued" : behavior === "followUp" ? "message queued" : "prompt accepted", "active");
     void session.prompt(text, behavior === undefined ? undefined : { streamingBehavior: behavior }).catch((error: unknown) => {
@@ -255,6 +257,28 @@ export class PiSessionService {
     this.active.set(session.sessionId, active);
   }
 
+  private maybeGenerateSessionName(session: AgentSession, firstMessage: string): void {
+    if (session.sessionName !== undefined || session.messages.length !== 0 || session.isStreaming || session.isCompacting) return;
+    const model = session.model;
+    if (model === undefined) return;
+
+    void generateShortSessionName(this.modelRegistry, model, firstMessage).then((name) => {
+      if (name === undefined || session.sessionName !== undefined) return;
+      session.setSessionName(name);
+      this.publishSessionName(session);
+    }).catch(() => {
+      // Session naming is best-effort and must not affect prompt handling.
+    });
+  }
+
+  private publishSessionName(session: AgentSession): void {
+    const event = session.sessionName === undefined
+      ? { type: "session.name", sessionId: session.sessionId } as const
+      : { type: "session.name", sessionId: session.sessionId, name: session.sessionName } as const;
+    this.events.publish(session.sessionId, event);
+    this.events.publishGlobal(event);
+  }
+
   private publishHeartbeats(): void {
     for (const active of this.active.values()) {
       const { session } = active.runtime;

src/server/sessions/sessionNameGenerator.ts

@@ -0,0 +1,66 @@
+import { getApiProvider, type Api, type AssistantMessage, type Model } from "@earendil-works/pi-ai";
+import type { ModelRegistry } from "@earendil-works/pi-coding-agent";
+
+const SESSION_NAME_TIMEOUT_MS = 10_000;
+const SESSION_NAME_MAX_INPUT_CHARS = 4_000;
+const SESSION_NAME_MAX_LENGTH = 60;
+
+export async function generateShortSessionName<TApi extends Api>(modelRegistry: ModelRegistry, model: Model<TApi>, firstMessage: string): Promise<string | undefined> {
+  const provider = getApiProvider(model.api);
+  if (provider === undefined) return undefined;
+
+  const auth = await modelRegistry.getApiKeyAndHeaders(model);
+  if (!auth.ok) return undefined;
+
+  const stream = provider.streamSimple(
+    model,
+    {
+      systemPrompt: "Generate a concise title for a coding-agent chat session. Return only the title, with no quotes or punctuation wrapper.",
+      messages: [{
+        role: "user",
+        content: `Create a 2-6 word title for this request:\n\n${truncateInput(firstMessage)}`,
+        timestamp: Date.now(),
+      }],
+    },
+    {
+      temperature: 0.2,
+      maxTokens: 24,
+      reasoning: "minimal",
+      signal: AbortSignal.timeout(SESSION_NAME_TIMEOUT_MS),
+      ...(auth.apiKey === undefined ? {} : { apiKey: auth.apiKey }),
+      ...(auth.headers === undefined ? {} : { headers: auth.headers }),
+    },
+  );
+
+  let streamedText = "";
+  let finalMessage: AssistantMessage | undefined;
+  for await (const event of stream) {
+    if (event.type === "text_delta") streamedText += event.delta;
+    if (event.type === "done") finalMessage = event.message;
+    if (event.type === "error") return undefined;
+  }
+
+  return cleanSessionName(finalMessage === undefined ? streamedText : textFromAssistant(finalMessage));
+}
+
+export function cleanSessionName(value: string): string | undefined {
+  const title = (value.split("\n", 1)[0] ?? "")
+    .replace(/^\s*["'`]+|["'`.]+\s*$/g, "")
+    .replace(/^(title|session title)\s*:\s*/i, "")
+    .replace(/\s+/g, " ")
+    .trim()
+    .slice(0, SESSION_NAME_MAX_LENGTH)
+    .trim();
+  return title === "" ? undefined : title;
+}
+
+function textFromAssistant(message: AssistantMessage): string {
+  return message.content
+    .filter((part) => part.type === "text")
+    .map((part) => part.text)
+    .join("");
+}
+
+function truncateInput(value: string): string {
+  return value.length <= SESSION_NAME_MAX_INPUT_CHARS ? value : `${value.slice(0, SESSION_NAME_MAX_INPUT_CHARS)}…`;
+}