diff --git a/src/server/services/session-metadata.ts b/src/server/services/session-metadata.ts
new file mode 100644
index 0000000..fe54144
--- /dev/null
+++ b/src/server/services/session-metadata.ts
@@ -0,0 +1,65 @@
+import {
+  forEachJsonlLine,
+  countMessagesForLine,
+  classifyLine,
+} from "./session-parser.js";
+import type { RawLine } from "./session-parser.js";
+
+export interface SessionMetadata {
+  messageCount: number;
+  firstPrompt: string;
+  summary: string;
+  firstTimestamp: string;
+  lastTimestamp: string;
+  parseErrors: number;
+}
+
+const MAX_FIRST_PROMPT_LENGTH = 200;
+
+export function extractSessionMetadata(content: string): SessionMetadata {
+  let messageCount = 0;
+  let firstPrompt = "";
+  let summary = "";
+  let firstTimestamp = "";
+  let lastTimestamp = "";
+
+  const { parseErrors } = forEachJsonlLine(content, (parsed: RawLine) => {
+    messageCount += countMessagesForLine(parsed);
+
+    if (parsed.timestamp) {
+      if (!firstTimestamp) {
+        firstTimestamp = parsed.timestamp;
+      }
+      lastTimestamp = parsed.timestamp;
+    }
+
+    if (!firstPrompt && classifyLine(parsed) === "user") {
+      const msgContent = parsed.message?.content;
+      if (typeof msgContent === "string" && !isSystemReminder(msgContent)) {
+        firstPrompt = truncate(msgContent, MAX_FIRST_PROMPT_LENGTH);
+      }
+    }
+
+    if (parsed.type === "summary" && parsed.summary) {
+      summary = parsed.summary;
+    }
+  });
+
+  return {
+    messageCount,
+    firstPrompt,
+    summary,
+    firstTimestamp,
+    lastTimestamp,
+    parseErrors,
+  };
+}
+
+function isSystemReminder(text: string): boolean {
+  return text.includes("<system-reminder>") || text.includes("</system-reminder>");
+}
+
+function truncate(text: string, maxLength: number): string {
+  if (text.length <= maxLength) return text;
+  return text.slice(0, maxLength);
+}
diff --git a/tests/unit/session-metadata.test.ts b/tests/unit/session-metadata.test.ts
new file mode 100644
index 0000000..3f4a3e8
--- /dev/null
+++ b/tests/unit/session-metadata.test.ts
@@ -0,0 +1,192 @@
+import { describe, it, expect } from "vitest";
+import { extractSessionMetadata } from "../../src/server/services/session-metadata.js";
+import { parseSessionContent } from "../../src/server/services/session-parser.js";
+import fs from "fs/promises";
+import path from "path";
+
+describe("session-metadata", () => {
+  it("messageCount matches parseSessionContent on sample-session.jsonl", async () => {
+    const fixturePath = path.join(__dirname, "../fixtures/sample-session.jsonl");
+    const content = await fs.readFile(fixturePath, "utf-8");
+
+    const meta = extractSessionMetadata(content);
+    const parsed = parseSessionContent(content);
+
+    expect(meta.messageCount).toBe(parsed.length);
+  });
+
+  it("messageCount matches parseSessionContent on edge-cases.jsonl", async () => {
+    const fixturePath = path.join(__dirname, "../fixtures/edge-cases.jsonl");
+    const content = await fs.readFile(fixturePath, "utf-8");
+
+    const meta = extractSessionMetadata(content);
+    const parsed = parseSessionContent(content);
+
+    expect(meta.messageCount).toBe(parsed.length);
+  });
+
+  it("firstPrompt skips system-reminder messages", () => {
+    const content = [
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "<system-reminder>hook output</system-reminder>" },
+        uuid: "u-sr",
+        timestamp: "2025-01-01T00:00:00Z",
+      }),
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "What is the project structure?" },
+        uuid: "u-real",
+        timestamp: "2025-01-01T00:00:01Z",
+      }),
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstPrompt).toBe("What is the project structure?");
+  });
+
+  it("firstPrompt truncated to 200 chars", () => {
+    const longMessage = "a".repeat(300);
+    const content = JSON.stringify({
+      type: "user",
+      message: { role: "user", content: longMessage },
+      uuid: "u-long",
+      timestamp: "2025-01-01T00:00:00Z",
+    });
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstPrompt).toHaveLength(200);
+    expect(meta.firstPrompt).toBe("a".repeat(200));
+  });
+
+  it("summary captures the LAST summary line", () => {
+    const content = [
+      JSON.stringify({ type: "summary", summary: "First summary", uuid: "s-1" }),
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "Hello" },
+        uuid: "u-1",
+      }),
+      JSON.stringify({ type: "summary", summary: "Last summary", uuid: "s-2" }),
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.summary).toBe("Last summary");
+  });
+
+  it("timestamps captured from first and last lines with timestamps", () => {
+    const content = [
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "Hello" },
+        uuid: "u-1",
+        timestamp: "2025-01-01T10:00:00Z",
+      }),
+      JSON.stringify({
+        type: "assistant",
+        message: { role: "assistant", content: "Hi" },
+        uuid: "a-1",
+        timestamp: "2025-01-01T10:05:00Z",
+      }),
+      JSON.stringify({
+        type: "summary",
+        summary: "Session done",
+        uuid: "s-1",
+      }),
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstTimestamp).toBe("2025-01-01T10:00:00Z");
+    expect(meta.lastTimestamp).toBe("2025-01-01T10:05:00Z");
+  });
+
+  it("empty content returns zero counts and empty strings", () => {
+    const meta = extractSessionMetadata("");
+    expect(meta.messageCount).toBe(0);
+    expect(meta.firstPrompt).toBe("");
+    expect(meta.summary).toBe("");
+    expect(meta.firstTimestamp).toBe("");
+    expect(meta.lastTimestamp).toBe("");
+    expect(meta.parseErrors).toBe(0);
+  });
+
+  it("JSONL with no user messages returns empty firstPrompt", () => {
+    const content = [
+      JSON.stringify({ type: "summary", summary: "No user", uuid: "s-1" }),
+      JSON.stringify({ type: "progress", data: { type: "hook" }, uuid: "p-1" }),
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstPrompt).toBe("");
+  });
+
+  it("JSONL with all system-reminder users returns empty firstPrompt", () => {
+    const content = [
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "<system-reminder>r1</system-reminder>" },
+        uuid: "u-1",
+      }),
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "<system-reminder>r2</system-reminder>" },
+        uuid: "u-2",
+      }),
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstPrompt).toBe("");
+  });
+
+  it("single-line JSONL: firstTimestamp equals lastTimestamp", () => {
+    const content = JSON.stringify({
+      type: "user",
+      message: { role: "user", content: "solo" },
+      uuid: "u-solo",
+      timestamp: "2025-06-15T12:00:00Z",
+    });
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstTimestamp).toBe("2025-06-15T12:00:00Z");
+    expect(meta.lastTimestamp).toBe("2025-06-15T12:00:00Z");
+  });
+
+  it("reports parseErrors from malformed lines", () => {
+    const content = [
+      "broken json",
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "ok" },
+        uuid: "u-1",
+      }),
+      "{truncated",
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.parseErrors).toBe(2);
+    expect(meta.messageCount).toBe(1);
+  });
+
+  it("skips array user content for firstPrompt (only captures string content)", () => {
+    const content = [
+      JSON.stringify({
+        type: "user",
+        message: {
+          role: "user",
+          content: [
+            { type: "tool_result", tool_use_id: "t1", content: "result" },
+          ],
+        },
+        uuid: "u-arr",
+      }),
+      JSON.stringify({
+        type: "user",
+        message: { role: "user", content: "Second prompt as string" },
+        uuid: "u-str",
+      }),
+    ].join("\n");
+
+    const meta = extractSessionMetadata(content);
+    expect(meta.firstPrompt).toBe("Second prompt as string");
+  });
+});