diff --git a/src/index.ts b/src/index.ts
index 68bdab6..67636ff 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -196,6 +196,14 @@ export function parseTimePhrase(query: string, now: number): { after?: number; b
   return { cleanQuery: query };
 }
 
+// ─── Hashtag extraction ───────────────────────────────────────────────────────
+
+export function extractHashtags(content: string): { cleanContent: string; hashtags: string[] } {
+  const hashtags = (content.match(/#\w+/g) ?? []).map(t => t.slice(1).toLowerCase());
+  const cleanContent = content.replace(/#\w+/g, '').replace(/\s+/g, ' ').trim();
+  return { cleanContent, hashtags };
+}
+
 // ─── Store entry (full embed + chunk) ────────────────────────────────────────
 // Returns the list of vector IDs inserted so forget() can clean up exactly.
 
@@ -317,8 +325,10 @@ function buildMcpServer(env: Env): McpServer {
       source: z.string().optional().describe("Origin: phone, browser, voice, claude"),
     },
     async ({ content, tags, source }) => {
-      const c = content.trim();
-      const t = tags ?? [];
+      const raw = content.trim();
+      const { cleanContent, hashtags } = extractHashtags(raw);
+      const c = cleanContent || raw;
+      const t = [...new Set([...(tags ?? []).map(tag => tag.toLowerCase()), ...hashtags])];
       const s = source ?? "claude";
 
       const dup = await checkDuplicate(c, env);
@@ -593,8 +603,10 @@ export default {
       try { body = await request.json(); } catch { return json({ error: "Invalid JSON" }, 400); }
       if (!body.content?.trim()) return json({ error: "content is required" }, 400);
 
-      const c = body.content.trim();
-      const t = body.tags ?? [];
+      const raw = body.content.trim();
+      const { cleanContent, hashtags } = extractHashtags(raw);
+      const c = cleanContent || raw;
+      const t = [...new Set([...(body.tags ?? []).map(tag => tag.toLowerCase()), ...hashtags])];
       const s = body.source ?? "api";
 
       const dup = await checkDuplicate(c, env);
diff --git a/test/integration/capture.test.ts b/test/integration/capture.test.ts
index 1a7d3d9..1dddb10 100644
--- a/test/integration/capture.test.ts
+++ b/test/integration/capture.test.ts
@@ -63,6 +63,51 @@ describe("POST /capture", () => {
     expect(db.entries).toHaveLength(0);
   });
 
+  it("extracts hashtags from content and stores clean content with tags", async () => {
+    const { ctx, drain } = makeCtx();
+    const res = await worker.fetch(req("POST", "/capture", { body: { content: "went for a run #health #fitness" } }), env, ctx);
+    await drain();
+    expect(res.status).toBe(200);
+    const data = await res.json() as any;
+    expect(data.ok).toBe(true);
+    expect(db.entries).toHaveLength(1);
+    expect(db.entries[0].content).toBe("went for a run");
+    const tags = JSON.parse(db.entries[0].tags);
+    expect(tags).toContain("health");
+    expect(tags).toContain("fitness");
+  });
+
+  it("merges hashtag tags with explicit tags and deduplicates case-insensitively", async () => {
+    const { ctx, drain } = makeCtx();
+    const res = await worker.fetch(req("POST", "/capture", { body: { content: "note #health", tags: ["Health", "fitness"] } }), env, ctx);
+    await drain();
+    expect(res.status).toBe(200);
+    const tags: string[] = JSON.parse(db.entries[0].tags);
+    const healthCount = tags.filter(t => t === "health").length;
+    expect(healthCount).toBe(1);
+    expect(tags).toContain("fitness");
+  });
+
+  it("behaves identically when no hashtags are present (regression)", async () => {
+    const { ctx, drain } = makeCtx();
+    const res = await worker.fetch(req("POST", "/capture", { body: { content: "plain note", tags: ["work"] } }), env, ctx);
+    await drain();
+    expect(res.status).toBe(200);
+    expect(db.entries[0].content).toBe("plain note");
+    const tags = JSON.parse(db.entries[0].tags);
+    expect(tags).toEqual(["work"]);
+  });
+
+  it("falls back to original content when input is only hashtags", async () => {
+    const { ctx, drain } = makeCtx();
+    const res = await worker.fetch(req("POST", "/capture", { body: { content: "#task" } }), env, ctx);
+    await drain();
+    expect(res.status).toBe(200);
+    expect(db.entries[0].content).toBe("#task");
+    const tags = JSON.parse(db.entries[0].tags);
+    expect(tags).toContain("task");
+  });
+
   it("stores flagged duplicate (score 0.85–0.94) with duplicate-candidate tag", async () => {
     const vectorize = makeVectorizeMock({
       query: vi.fn().mockResolvedValue({
diff --git a/test/unit/extract-hashtags.test.ts b/test/unit/extract-hashtags.test.ts
new file mode 100644
index 0000000..f528c62
--- /dev/null
+++ b/test/unit/extract-hashtags.test.ts
@@ -0,0 +1,52 @@
+import { describe, it, expect } from "vitest";
+import { extractHashtags } from "../../src/index";
+
+describe("extractHashtags", () => {
+  it("returns empty hashtags and unchanged content when no hashtags present", () => {
+    const { cleanContent, hashtags } = extractHashtags("plain text");
+    expect(cleanContent).toBe("plain text");
+    expect(hashtags).toEqual([]);
+  });
+
+  it("extracts a single hashtag and strips it from content", () => {
+    const { cleanContent, hashtags } = extractHashtags("note #health");
+    expect(cleanContent).toBe("note");
+    expect(hashtags).toEqual(["health"]);
+  });
+
+  it("extracts multiple hashtags", () => {
+    const { cleanContent, hashtags } = extractHashtags("note #health #fitness");
+    expect(cleanContent).toBe("note");
+    expect(hashtags).toEqual(["health", "fitness"]);
+  });
+
+  it("extracts a hashtag mid-sentence and collapses whitespace", () => {
+    const { cleanContent, hashtags } = extractHashtags("went #health for a run");
+    expect(cleanContent).toBe("went for a run");
+    expect(hashtags).toEqual(["health"]);
+  });
+
+  it("lowercases hashtags", () => {
+    const { cleanContent, hashtags } = extractHashtags("note #Health #FITNESS");
+    expect(cleanContent).toBe("note");
+    expect(hashtags).toEqual(["health", "fitness"]);
+  });
+
+  it("returns empty cleanContent when content is only hashtags", () => {
+    const { cleanContent, hashtags } = extractHashtags("#task");
+    expect(cleanContent).toBe("");
+    expect(hashtags).toEqual(["task"]);
+  });
+
+  it("collapses extra whitespace left by removed hashtags", () => {
+    const { cleanContent, hashtags } = extractHashtags("a #b c");
+    expect(cleanContent).toBe("a c");
+    expect(hashtags).toEqual(["b"]);
+  });
+
+  it("handles hashtags with underscores and digits", () => {
+    const { cleanContent, hashtags } = extractHashtags("note #tag_1 #item2");
+    expect(cleanContent).toBe("note");
+    expect(hashtags).toEqual(["tag_1", "item2"]);
+  });
+});