diff --git a/apps/planner/app/lib/overpass.test.ts b/apps/planner/app/lib/overpass.test.ts
index b462e5b..0e284e3 100644
--- a/apps/planner/app/lib/overpass.test.ts
+++ b/apps/planner/app/lib/overpass.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { buildQuery, parseResponse, deduplicateById, type Poi } from "./overpass.ts";
+import { buildQuery, parseResponse, deduplicateById, quantizeBbox, type Poi } from "./overpass.ts";
 import { poiCategories } from "@trails-cool/map-core";
 
 describe("buildQuery", () => {
@@ -9,7 +9,7 @@ describe("buildQuery", () => {
     const query = buildQuery(bbox, categories);
 
     expect(query).toContain("[out:json]");
-    expect(query).toContain("[bbox:52.5,13.3,52.6,13.5]");
+    expect(query).toContain("[bbox:52.500,13.300,52.600,13.500]");
     expect(query).toContain('amenity"="drinking_water"');
     expect(query).toContain("out center qt 100");
   });
@@ -22,6 +22,45 @@ describe("buildQuery", () => {
     expect(query).toContain("drinking_water");
     expect(query).toContain("camp_site");
   });
+
+  it("produces identical queries for near-identical viewports within one grid cell", () => {
+    const categories = poiCategories.filter((c) => c.id === "drinking_water");
+    const a = buildQuery(
+      { south: 52.5041, west: 13.3072, north: 52.5931, east: 13.4928 },
+      categories,
+    );
+    const b = buildQuery(
+      { south: 52.5039, west: 13.3078, north: 52.5925, east: 13.4921 },
+      categories,
+    );
+    expect(a).toBe(b);
+  });
+
+  it("expands the bbox outward so the original viewport is always covered", () => {
+    const categories = poiCategories.filter((c) => c.id === "drinking_water");
+    const query = buildQuery(
+      { south: 52.5041, west: 13.3072, north: 52.5931, east: 13.4928 },
+      categories,
+    );
+    expect(query).toContain("[bbox:52.500,13.300,52.600,13.500]");
+  });
+});
+
+describe("quantizeBbox", () => {
+  it("snaps south and west down, north and east up", () => {
+    const q = quantizeBbox({ south: 52.5041, west: 13.3072, north: 52.5931, east: 13.4928 }, 0.01);
+    expect(q.south).toBeCloseTo(52.5, 10);
+    expect(q.west).toBeCloseTo(13.3, 10);
+    expect(q.north).toBeCloseTo(52.6, 10);
+    expect(q.east).toBeCloseTo(13.5, 10);
+  });
+
+  it("is idempotent on already-aligned coordinates", () => {
+    const bbox = { south: 52.5, west: 13.3, north: 52.6, east: 13.5 };
+    const q = quantizeBbox(bbox, 0.01);
+    expect(q.south).toBeCloseTo(52.5, 10);
+    expect(q.north).toBeCloseTo(52.6, 10);
+  });
 });
 
 describe("parseResponse", () => {
diff --git a/apps/planner/app/lib/overpass.ts b/apps/planner/app/lib/overpass.ts
index 6a14fbd..ac04eaa 100644
--- a/apps/planner/app/lib/overpass.ts
+++ b/apps/planner/app/lib/overpass.ts
@@ -2,6 +2,18 @@ import type { PoiCategory } from "@trails-cool/map-core";
 
 const OVERPASS_PROXY = "/api/overpass";
 
+// Snap bbox coordinates to this grid before building the query so that two
+// users looking at nearly-identical viewports produce byte-identical queries
+// and therefore share a server-side cache entry. Expansion is outward
+// (south/west floor, north/east ceil) so the user's viewport is always
+// covered. ~0.01° ≈ 1 km at mid-latitudes.
+const BBOX_GRID_STEP = 0.01;
+
+// Decimals used when formatting the quantized bbox into the query string.
+// 3 decimals → 0.001° precision (~111 m) which is well below BBOX_GRID_STEP,
+// so the string is a stable representation of the quantized cell.
+const BBOX_DECIMALS = 3;
+
 export interface Poi {
   id: number;
   lat: number;
@@ -18,11 +30,31 @@ export interface BBox {
   east: number;
 }
 
+/**
+ * Quantize a bbox to the grid defined by `BBOX_GRID_STEP`, expanding outward
+ * so the original bbox is fully contained. Returns a new BBox whose
+ * coordinates are cell-aligned.
+ */
+export function quantizeBbox(bbox: BBox, step: number = BBOX_GRID_STEP): BBox {
+  return {
+    south: Math.floor(bbox.south / step) * step,
+    west: Math.floor(bbox.west / step) * step,
+    north: Math.ceil(bbox.north / step) * step,
+    east: Math.ceil(bbox.east / step) * step,
+  };
+}
+
 /**
  * Build an Overpass QL query combining all enabled categories into a union.
+ * The bbox is quantized to a fixed grid and formatted with a fixed number of
+ * decimals so near-identical viewports produce a byte-identical query — which
+ * the `/api/overpass` server-side cache keys on.
  */
 export function buildQuery(bbox: BBox, categories: PoiCategory[]): string {
-  const bboxStr = `${bbox.south},${bbox.west},${bbox.north},${bbox.east}`;
+  const q = quantizeBbox(bbox);
+  const bboxStr = [q.south, q.west, q.north, q.east]
+    .map((n) => n.toFixed(BBOX_DECIMALS))
+    .join(",");
   const unions = categories.map((c) => c.query).join("");
   return `[out:json][timeout:10][maxsize:1048576][bbox:${bboxStr}];(${unions});out center qt 100;`;
 }
diff --git a/openspec/changes/legal-disclaimers/.openspec.yaml b/openspec/changes/archive/2026-04-18-legal-disclaimers/.openspec.yaml
similarity index 100%
rename from openspec/changes/legal-disclaimers/.openspec.yaml
rename to openspec/changes/archive/2026-04-18-legal-disclaimers/.openspec.yaml
diff --git a/openspec/changes/legal-disclaimers/design.md b/openspec/changes/archive/2026-04-18-legal-disclaimers/design.md
similarity index 100%
rename from openspec/changes/legal-disclaimers/design.md
rename to openspec/changes/archive/2026-04-18-legal-disclaimers/design.md
diff --git a/openspec/changes/legal-disclaimers/proposal.md b/openspec/changes/archive/2026-04-18-legal-disclaimers/proposal.md
similarity index 100%
rename from openspec/changes/legal-disclaimers/proposal.md
rename to openspec/changes/archive/2026-04-18-legal-disclaimers/proposal.md
diff --git a/openspec/changes/legal-disclaimers/specs/journal-auth/spec.md b/openspec/changes/archive/2026-04-18-legal-disclaimers/specs/journal-auth/spec.md
similarity index 100%
rename from openspec/changes/legal-disclaimers/specs/journal-auth/spec.md
rename to openspec/changes/archive/2026-04-18-legal-disclaimers/specs/journal-auth/spec.md
diff --git a/openspec/changes/legal-disclaimers/specs/legal-disclaimers/spec.md b/openspec/changes/archive/2026-04-18-legal-disclaimers/specs/legal-disclaimers/spec.md
similarity index 100%
rename from openspec/changes/legal-disclaimers/specs/legal-disclaimers/spec.md
rename to openspec/changes/archive/2026-04-18-legal-disclaimers/specs/legal-disclaimers/spec.md
diff --git a/openspec/changes/legal-disclaimers/tasks.md b/openspec/changes/archive/2026-04-18-legal-disclaimers/tasks.md
similarity index 91%
rename from openspec/changes/legal-disclaimers/tasks.md
rename to openspec/changes/archive/2026-04-18-legal-disclaimers/tasks.md
index f82543f..c8bb718 100644
--- a/openspec/changes/legal-disclaimers/tasks.md
+++ b/openspec/changes/archive/2026-04-18-legal-disclaimers/tasks.md
@@ -40,7 +40,7 @@
 
 ## 7. Review & Publish
 
-- [ ] 7.1 Get the drafted German and English legal text reviewed by a German IT lawyer before treating as final
-- [ ] 7.2 Deploy and verify all three legal pages render correctly at their URLs
-- [ ] 7.3 Verify registration blocks without acknowledgement and records the timestamp on success
-- [ ] 7.4 Verify the alpha banner appears and dismisses correctly
+- [x] 7.1 Get the drafted German and English legal text reviewed by a German IT lawyer before treating as final
+- [x] 7.2 Deploy and verify all three legal pages render correctly at their URLs
+- [x] 7.3 Verify registration blocks without acknowledgement and records the timestamp on success
+- [x] 7.4 Verify the alpha banner appears and dismisses correctly
diff --git a/openspec/specs/journal-auth/spec.md b/openspec/specs/journal-auth/spec.md
index ffd4d34..2b2fb24 100644
--- a/openspec/specs/journal-auth/spec.md
+++ b/openspec/specs/journal-auth/spec.md
@@ -11,3 +11,19 @@ The journal auth system SHALL store OAuth tokens for external services alongside
 - **WHEN** a user connects their Wahoo account
 - **THEN** access token, refresh token, expiry time, and Wahoo user ID are stored in the `wahoo_tokens` table
 - **AND** tokens are associated with the journal user ID
+
+### Requirement: Terms acknowledgement at signup
+The registration form SHALL require explicit acknowledgement of the Terms of Service before an account can be created.
+
+#### Scenario: Checkbox required
+- **WHEN** a user views the registration form
+- **THEN** they see a required checkbox labeled "I have read and agree to the Terms of Service, including that trails.cool is in alpha and my data may be reset"
+- **AND** the checkbox label links to the Terms page
+
+#### Scenario: Cannot submit without acknowledgement
+- **WHEN** a user attempts to register without checking the acknowledgement box
+- **THEN** the form blocks submission and shows a validation message
+
+#### Scenario: Acknowledgement recorded
+- **WHEN** a user successfully registers
+- **THEN** the current timestamp is stored in `users.terms_accepted_at`
diff --git a/openspec/specs/legal-disclaimers/spec.md b/openspec/specs/legal-disclaimers/spec.md
new file mode 100644
index 0000000..1363e8a
--- /dev/null
+++ b/openspec/specs/legal-disclaimers/spec.md
@@ -0,0 +1,77 @@
+## Purpose
+
+Legal pages, signup acknowledgement, and alpha-state disclosures required for operating trails.cool under German law (TMG, MStV, GDPR).
+
+## Requirements
+
+### Requirement: Impressum page
+The Journal SHALL serve an Impressum page at `/legal/imprint` containing the operator's legal information per §5 TMG and §18 MStV.
+
+#### Scenario: Impressum is accessible
+- **WHEN** a user navigates to `/legal/imprint`
+- **THEN** they see a page with the operator's full name, postal address, email address, and the responsible person per §18 Abs. 2 MStV
+
+#### Scenario: Impressum is linked from footer
+- **WHEN** a user views any page on the Journal or Planner
+- **THEN** the footer contains a link to the Impressum
+
+### Requirement: Terms of Service page
+The Journal SHALL serve a Terms of Service page at `/legal/terms` with clear disclaimers about the service's alpha state.
+
+#### Scenario: Alpha status disclosure
+- **WHEN** a user reads the Terms page
+- **THEN** the Terms clearly state that the service is in early development, untested, and may change without notice
+
+#### Scenario: Database reset disclosure
+- **WHEN** a user reads the Terms page
+- **THEN** the Terms explicitly state that the operator may delete all user data at any time without prior notice
+
+#### Scenario: Warranty disclaimer
+- **WHEN** a user reads the Terms page
+- **THEN** the Terms disclaim all warranties to the extent permitted by German consumer law
+
+#### Scenario: Data export responsibility
+- **WHEN** a user reads the Terms page
+- **THEN** the Terms state that the user is responsible for exporting their own data and link to the data export functionality
+
+### Requirement: Datenschutzerklärung
+The Journal SHALL serve a GDPR-compliant privacy policy at `/legal/privacy`, replacing the existing `/privacy` route.
+
+#### Scenario: Controller contact
+- **WHEN** a user reads the Datenschutzerklärung
+- **THEN** they see the name, address, and email of the data controller (Verantwortlicher per Art. 4 Nr. 7 DSGVO)
+
+#### Scenario: Legal basis for processing
+- **WHEN** a user reads the Datenschutzerklärung
+- **THEN** each category of data processing lists its legal basis (e.g., Art. 6 Abs. 1 lit. b for contract, lit. f for legitimate interest)
+
+#### Scenario: Data subject rights
+- **WHEN** a user reads the Datenschutzerklärung
+- **THEN** they see their rights under GDPR: access (Art. 15), rectification (Art. 16), erasure (Art. 17), data portability (Art. 20), objection (Art. 21), and right to lodge a complaint with a supervisory authority
+
+#### Scenario: Redirect from old privacy URL
+- **WHEN** a user navigates to `/privacy`
+- **THEN** they are redirected to `/legal/privacy` with a 301 status
+
+### Requirement: Alpha banner
+The Journal SHALL display a persistent banner notifying users that the service is in alpha, dismissible for the browser session.
+
+#### Scenario: Banner visible on first visit
+- **WHEN** a user visits any Journal page for the first time in a session
+- **THEN** a banner is shown with text stating trails.cool is in early development and data may be reset, with a link to the Terms
+
+#### Scenario: Banner dismissible
+- **WHEN** a user clicks the dismiss button on the alpha banner
+- **THEN** the banner is hidden for the remainder of the browser session (via sessionStorage)
+- **AND** the banner reappears in a new session
+
+### Requirement: Footer legal links
+Both the Journal and Planner SHALL render a footer with links to Impressum, Datenschutzerklärung, and Terms.
+
+#### Scenario: Footer on Journal
+- **WHEN** a user views any Journal page
+- **THEN** the footer contains links labeled "Impressum", "Privacy", and "Terms" pointing to the respective legal pages
+
+#### Scenario: Footer on Planner
+- **WHEN** a user views any Planner page
+- **THEN** the footer contains the same three legal links, pointing to the Journal instance (since the Planner is stateless and legal pages live on the Journal)