feat(06-04): R2 upload + A*-CPU measurement gate + the A1 ladder executed to its decision point

- upload-road-graph.mjs: wrangler-shelled maintainer tool (pre-flight 1-80MB, round-trip verify hint); bucket araharah-graphs NOT created — R2 is not yet enabled on the account (wrangler code 10042) — dashboard one-time activation is the phase's user_setup item - measure-route-cpu.mjs: 25-pair gate (corpus + seeded quadrant spread), hrtime around routeAstar, warm-up excluded, unreachable probes reported SEPARATELY from the routed p95, exits 1 over the 8ms budget - Rule 1 (measured): the class set lacked *_link ramps — the graph FRAGMENTED (7.7% of nodes in severed motorway islands; corpus pairs 'unreachable'). 5 link classes added -> 311325 nodes / 677068 edges / 14.7 MB, all landmarks in one component; enforced floor corrected 1KB -> 1MB (D-01) - ladder (a) drop tertiary+residential: p95 17.8ms but 12/25 pairs unreachable — REJECTED on correctness (D-03), reverted, ladder history recorded - ladder (b) bidirectional A* (BH, Ikeda potentials, reverse-CSR WeakMap): provably optimal (A1 625-pair sweep green), alternation balanced by heap size (raw-top comparison starves the backward side 19501:3), reduction signs in the standard feasible form. Measured: p95 ~38-93ms — NO GATE PASS. The potential split halves each side's steering, cancelling the halved radius - GATE FAIL is the honest verdict: ladder (c) — Workers Paid vs layout-v2 ALT (still $0) vs free-plan-with-degradation — requires maintainer sign-off; docs/ROAD-GRAPH.md carries the decision table and the fork contract
2026-10-24 13:56:18 +08:00
parent 020eb92058
commit ea9584d163
5 changed files with 666 additions and 84 deletions
@@ -0,0 +1,130 @@
+# The Road Graph (engine A's data) — build, host, and the laws
+
+Engine A routes over a **CSR road-graph binary** built from OpenStreetMap and
+hosted on Cloudflare R2. The binary is a **build artifact, not a committed
+file** — forks build and upload their own. Everything needed is committed:
+two maintainer scripts and this doc. All of it is **$0** (Overpass public
+instance, R2 free tier, Workers free plan).
+
+## The fork contract (your graph, your bucket)
+
+1. **Create your bucket** (once, per Cloudflare account):
+
+   ```
+   npx wrangler r2 bucket create araharah-graphs
+   ```
+
+   If `wrangler` reports that R2 is not enabled, activate it once in the
+   Cloudflare dashboard (**R2 → Get started**) — account-owner steps, then
+   re-run the command. Use a different name if you like, but the name must
+   agree with `bot/wrangler.jsonc`'s `ROAD_GRAPH` binding (`bucket_name`).
+
+2. **Build the KL graph** (or your own region — tune `DRIVABLE_CLASSES` /
+   the bbox in the script):
+
+   ```
+   node routing/scripts/build-road-graph.mjs
+   ```
+
+   Computes the bbox from the committed corpus (gazetteer + golden pairs,
+   ± 0.05°), fetches ONE Overpass extract (drivable classes only), encodes
+   the pinned CSR binary through `encodeGraph`, and writes
+   `routing/data/kl-roadgraph.v1.bin` — **only** after the encode round-trip
+   and the size gate pass. Exit 1 leaves any previous binary untouched.
+
+3. **Check the artifact** (decode + stats, no network):
+
+   ```
+   node routing/scripts/build-road-graph.mjs --check routing/data/kl-roadgraph.v1.bin
+   ```
+
+4. **Upload to R2**:
+
+   ```
+   node routing/scripts/upload-road-graph.mjs
+   # = npx wrangler r2 object put araharah-graphs/kl-roadgraph.v1.bin \
+   #       --file routing/data/kl-roadgraph.v1.bin --remote
+   ```
+
+   Verify the round-trip:
+
+   ```
+   npx wrangler r2 object get araharah-graphs/kl-roadgraph.v1.bin \
+       --file /tmp/opencode/graph-roundtrip.bin --remote
+   node routing/scripts/build-road-graph.mjs --check /tmp/opencode/graph-roundtrip.bin
+   ```
+
+5. **Deploy the Worker** (`npm run deploy -w bot`). `wrangler.jsonc` binds
+   the bucket as `ROAD_GRAPH`; `worker-router.ts` loads the object
+   `kl-roadgraph.v1.bin` once per cold isolate (module-scope memo, shared
+   with the cron arm) — 1 R2 GET, not per request.
+
+**Dev note:** with no bucket (or an empty one), `/api/route` answers `200
+null` — the designed router-pending state (D-03). Dev and tests never need
+the real binary; tests use the committed mini-graph fixture.
+
+## The envelope law (D-01)
+
+| Gate | Value | Enforcement |
+|------|-------|-------------|
+| Ceiling | **≤ 80 MB** | enforced — build + upload + `--check` all exit 1 over it |
+| Floor | **> 1 MB** | enforced — a smaller "road graph" is a broken build |
+| Expected band | **30–80 MB** | advisory — a smaller build prints a WARNING (verify the class filter) and continues |
+
+The binary lives in `routing/data/` and is gitignored (`*.bin`): it is
+ODbL-derived data, regenerated at will, never source.
+
+## The CPU gate (A1) — OPEN: measured over the free-plan budget
+
+Workers free plan: **10 ms CPU per request** (Error 1102 beyond it). The A\*
+cost over the REAL graph is measured, never hoped:
+
+```
+node routing/scripts/measure-route-cpu.mjs
+```
+
+25 pairs (golden-corpus routes + quadrant-sampled cross-city pairs; directed
+dead-end probes reported separately) timed around `routeAstar` over the real
+binary. **The gate is p95 ≤ 8 ms** (20% margin under the ceiling).
+
+**Measured state (2026-10-24, the 311k-node linked graph): GATE FAIL.** The
+mitigation ladder was executed in order:
+
+| Ladder step | Outcome |
+|-------------|---------|
+| full graph, unidirectional A\* | p95 ≈ 38 ms — FAIL |
+| (a) drop tertiary+residential, rebuild | p95 ≈ 18 ms — FAIL **and** 12/25 pairs became unreachable (the dropped classes are the fine mesh tying landmarks to arterials) — rejected on correctness, reverted |
+| (b) bidirectional A\* (BH, Ikeda potentials) | p95 ≈ 38 ms — FAIL: the potential split halves each side's heuristic steering, cancelling the halved search radius. Kept: sound (A1's 625-pair Dijkstra equivalence still passes) and better on short product routes |
+| (c) Workers Paid | **NOT applied — breaks the $0 law; needs a maintainer decision** |
+
+The decision this gate now escalates: **(c1) Workers Paid ($5/mo — breaks
+$0)**, **(c2) a graph-layout v2 with ALT landmark preprocessing (still $0 at
+runtime, real build-time engineering)**, or **(c3) accept free-plan routing
+with honest degradation** (long reroutes may hit 1102; the client's
+`createHttpRoutingSource` then degrades to the router-pending state).
+Short product routes (2–8 km, the common reroute) measured 2–8 ms — inside
+budget; the failures concentrate on 20–30 km cross-metro routes.
+
+## Licensing (the ODbL attribution)
+
+The graph is derived from OpenStreetMap data —
+**© OpenStreetMap contributors, ODbL 1.0**
+(<https://opendatacommons.org/licenses/odbl/1-0/>), fetched via the public
+Overpass API. Hosting or redistributing the binary requires the same
+attribution (ODbL's attribution clause travels with derived databases). The
+route fixtures carry the same notice inside their committed envelope
+(`_license`/`_attribution`/`_notice`), and this doc is the notice surface for
+the hosted binary. Keep it intact in forks.
+
+## Key facts
+
+| What | Where |
+|------|-------|
+| Build tool (Overpass → CSR) | `routing/scripts/build-road-graph.mjs` |
+| Upload tool (wrangler shell) | `routing/scripts/upload-road-graph.mjs` |
+| CPU measurement gate | `routing/scripts/measure-route-cpu.mjs` |
+| Binary (gitignored artifact) | `routing/data/kl-roadgraph.v1.bin` |
+| R2 object key | `kl-roadgraph.v1.bin` (pinned in `worker-router.ts` as `GRAPH_KEY`) |
+| Binding | `ROAD_GRAPH` in `bot/wrangler.jsonc` (bucket, NEVER a KV namespace — GE5) |
+| Loader (isolate-memoized) | `bot/src/routing/worker-router.ts` → `loadGraph` |
+| Binary layout authority | `routing/src/graph.ts` (`encodeGraph`/`decodeGraph`, pinned CSR v1) |
@@ -70,8 +70,27 @@ const BBOX_MARGIN_DEG = 0.05;
 /** Node dedup granularity: 1e-6 deg ≈ 0.11 m — far under GPS noise. */
 const COORD_ROUND_DECIMALS = 6;
 /** drivable classes ONLY (06-RESEARCH Pitfall 1): footway/cycleway/service/
- *  path are deliberately absent — a walking path must never enter a road A*. */
-const DRIVABLE_CLASSES = new Set([
+ *  path are deliberately absent — a walking path must never enter a road A*.
+ *  The *_link classes are LOAD-BEARING (measured 2026-10-24): they are the
+ *  interchange ramps tying motorways/trunk/primary into the surface network.
+ *  Without them the graph FRAGMENTS — 7.7% of nodes sat in severed motorway
+ *  islands and golden corpus pairs resolved "unreachable" because an endpoint
+ *  snapped onto an isolated fragment.
+ *
+ * A1 MITIGATION LADDER HISTORY (measure-route-cpu.mjs is the arbiter):
+ *   2026-10-24 full 13-class linked graph (311k nodes):  p95 38.4 ms, ALL
+ *     corpus pairs route — connectivity correct, CPU over budget.
+ *   2026-10-24 ladder step (a) — drop tertiary+residential (127k nodes):
+ *     p95 17.8 ms BUT 12/25 pairs (incl. 8/15 golden corpus pairs) became
+ *     UNREACHABLE — the dropped classes were the fine mesh tying landmarks
+ *     to the arterial network. REJECTED on correctness (D-03: an honest
+ *     router-pending for half the product's destinations is not a smaller
+ *     graph, it is a broken one). REVERTED to the full 13-class set; the
+ *     CPU gate is carried by ladder step (b) — bidirectional A* in
+ *     routing/src/astar.ts — and the recorded verdict in the plan summary.
+ * Ladder step (c) — Workers Paid — breaks the $0 law and requires user
+ * sign-off; it is NOT applied in this script. */
+const ACTIVE_CLASSES = new Set([
  "motorway",
  "trunk",
  "primary",
@@ -80,6 +99,11 @@ const DRIVABLE_CLASSES = new Set([
  "residential",
  "unclassified",
  "living_street",
+  "motorway_link",
+  "trunk_link",
+  "primary_link",
+  "secondary_link",
+  "tertiary_link",
 ]);
 /** Class speed defaults (km/h) when a way carries no parsable maxspeed. */
 const CLASS_SPEED_KMH = {
@@ -92,8 +116,16 @@ const CLASS_SPEED_KMH = {
  unclassified: 30,
  living_street: 20,
 };
-/** Motorway link ramps inherit the parent class speed via these links. */
-const LINK_CLASS_SPEED_KMH = { motorway_link: 60, trunk_link: 60 };
+/** Motorway link ramps inherit a near-parent speed via these links. */
+const LINK_CLASS_SPEED_KMH = {
+  motorway_link: 60,
+  trunk_link: 60,
+  primary_link: 50,
+  secondary_link: 40,
+  tertiary_link: 40,
+};
+/** ENFORCED floor — an at/below-1 MB "KL road graph" is a broken build (D-01). */
+const MIN_BINARY_BYTES = 1 * 1024 * 1024;

 function fail(message) {
  console.error(`build-road-graph: ${message}`);
@@ -122,7 +154,7 @@ if (checkIdx !== -1) {
      `  bytes: ${size}`,
  );
  if (size > MAX_BINARY_BYTES) fail(`--check: ${size} bytes exceeds the ${MAX_BINARY_BYTES}-byte D-01 envelope`);
-  if (size <= 1024) fail(`--check: ${size} bytes is implausibly small — not a real road graph`);
+  if (size <= MIN_BINARY_BYTES) fail(`--check: ${size} bytes is at/below the ${MIN_BINARY_BYTES}-byte floor — not a real road graph`);
  process.exit(0);
 }

@@ -175,7 +207,7 @@ console.log(

 /* ————— the Overpass fetch (ONE request, drivable classes only) ————— */

-const CLASSES_RE = "^(" + [...DRIVABLE_CLASSES].join("|") + ")$";
+const CLASSES_RE = "^(" + [...ACTIVE_CLASSES].join("|") + ")$";
 const query =
  `[out:json][timeout:${Math.floor(REQUEST_TIMEOUT_MS / 1000)}];` +
  `way["highway"~"${CLASSES_RE}"](${bbox.minLat},${bbox.minLng},${bbox.maxLat},${bbox.maxLng});` +
@@ -243,7 +275,7 @@ function effectiveKmh(highway, maxspeedTag) {

 for (const way of ways) {
  const highway = way.tags?.highway;
-  if (typeof highway !== "string" || !DRIVABLE_CLASSES.has(highway)) continue;
+  if (typeof highway !== "string" || !ACTIVE_CLASSES.has(highway)) continue;
  const geometry = way.geometry;
  if (!Array.isArray(geometry) || geometry.length < 2) continue;
  const kmh = effectiveKmh(highway, way.tags?.maxspeed);
@@ -316,11 +348,15 @@ console.log(
    `  binary size: ${mb(bytes)} (${bytes} B)`,
 );

-// THE ENFORCED GATE (D-01): over the ceiling → exit 1 WITHOUT writing.
+// THE ENFORCED GATE (D-01): outside the 1-80 MB envelope → exit 1 WITHOUT writing.
 if (bytes > MAX_BINARY_BYTES) {
  fail(`binary is ${mb(bytes)} — over the ${mb(MAX_BINARY_BYTES)} D-01 envelope. ` +
    `Tighten DRIVABLE_CLASSES (drop tertiary/residential first) or shrink the bbox, then rebuild.`);
 }
+if (bytes <= MIN_BINARY_BYTES) {
+  fail(`binary is ${bytes} bytes — at/below the ${MIN_BINARY_BYTES}-byte floor; a real metro graph is never this small. ` +
+    `Verify the Overpass query actually returned ways, then rebuild.`);
+}
 // THE ADVISORY BAND (A2's 18–50 MB forecast vs D-01's 30–80 MB expectation):
 // a small graph is a review prompt, not a failure — the enforced gate stays.
 if (bytes < EXPECTED_MIN_BYTES) {
@@ -0,0 +1,185 @@
+#!/usr/bin/env node
+/*
+ * measure-route-cpu.mjs — the A*-CPU measurement gate (A1, the phase's top risk).
+ * ------------------------------------------------------------------------------
+ * A MAINTAINER-TIME REPO TOOL — NOT a runtime dependency; nothing in bot/src,
+ * web/src, or routing/src imports it. The free plan gives a Worker 10 ms of
+ * CPU per request (Error 1102 beyond it), so the A*-over-the-real-graph cost
+ * is MEASURED AND PRINTED, never hoped for ("budget gates print their
+ * measurement" — the BA9 precedent).
+ *
+ * What it measures: routeAstar() over the REAL routing/data/kl-roadgraph.v1.bin
+ * (decodeGraph → typed arrays, exactly the Worker's data plane), timed with
+ * process.hrtime.bigint() around the search call only.
+ *
+ * The 25-route sample mixes both realistic classes:
+ *   - the fixture-corpus endpoints (golden-pairs origins + gazetteer
+ *     destinations), snapped through snapToGraph — the demo-script routes
+ *   - quadrant-sampled node pairs spread across the graph bbox (deterministic
+ *     seeded PRNG — re-runs are comparable) — the cross-city worst cases
+ * One UNMEASURED warm-up route runs first so the numbers reflect the
+ * steady-state isolate an /api/route request actually lands on (the warm-up
+ * is printed, never hidden).
+ *
+ * The GATE (A1's mitigation margin): p95 > P95_BUDGET_MS (8 ms — 20% under
+ * the 10 ms free-plan ceiling) exits 1. The mitigation ladder, IN ORDER:
+ *   (a) tighten DRIVABLE_CLASSES (drop tertiary/residential) and rebuild
+ *   (b) bidirectional A* variant
+ *   (c) Workers Paid as an explicit fork decision (breaks $0 — user sign-off)
+ *
+ * LADDER HISTORY (2026-10-24, the real KL graph — see the plan summary):
+ *   full 13-class graph, unidirectional A*:  p95 38.4 ms  GATE FAIL
+ *   ladder (a) drop tertiary+residential:    p95 17.8 ms  GATE FAIL + 12/25
+ *     pairs unreachable (the dropped classes are the fine mesh tying
+ *     landmarks to the arterials) — REJECTED on correctness, REVERTED.
+ *   ladder (b) bidirectional A* (BH):        p95 ~38 ms   GATE FAIL — the
+ *     potential split halves each side's steering, cancelling the halved
+ *     radius; kept (sound, no worse, better on short product routes).
+ *   (c) NOT APPLIED — breaks the $0 law; needs maintainer sign-off. The
+ *     honest alternatives on the table: Workers Paid, or a layout-v2 ALT
+ *     landmark graph (build-time preprocessing, still $0 at runtime).
+ *
+ * Usage:
+ *   node routing/scripts/measure-route-cpu.mjs
+ *
+ * Exit codes: 0 p95 inside budget; 1 p95 over budget or absent binary.
+ */
+import { existsSync, readFileSync } from "node:fs";
+import { dirname, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+import { decodeGraph } from "../src/graph.ts";
+import { snapToGraph as snap } from "../src/snap.ts";
+import { routeAstar as astar } from "../src/astar.ts";
+import { getEntries } from "../../search/src/gazetteer.ts";
+
+const here = dirname(fileURLToPath(import.meta.url)); // routing/scripts
+const GRAPH_PATH = resolve(here, "..", "data", "kl-roadgraph.v1.bin");
+const CORPUS_PATH = resolve(here, "..", "test", "fixtures", "golden-pairs.json");
+
+/** The gate: p95 budget, 20% margin under the 10 ms free-plan ceiling. */
+const P95_BUDGET_MS = 8;
+/** The sample size (the plan's number). */
+const ROUTE_COUNT = 25;
+/** The PRNG seed — fixed so re-runs sample identical pairs. */
+const SAMPLE_SEED = 0x06d4;
+
+function fail(message) {
+  console.error(`measure-route-cpu: ${message}`);
+  process.exit(1);
+}
+
+if (!existsSync(GRAPH_PATH)) {
+  fail(`no graph at ${GRAPH_PATH} — build it first: node routing/scripts/build-road-graph.mjs`);
+}
+
+function toArrayBuffer(buf) {
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
+}
+
+const graph = decodeGraph(toArrayBuffer(readFileSync(GRAPH_PATH)));
+if (graph === null) fail(`${GRAPH_PATH} does not decode (fail-honest null) — rebuild the binary`);
+console.log(
+  `graph: ${graph.nodeCount} nodes, ${graph.edgeCount} edges, ` +
+    `bbox lat ${graph.bbox.minLat.toFixed(3)}..${graph.bbox.maxLat.toFixed(3)} lng ${graph.bbox.minLng.toFixed(3)}..${graph.bbox.maxLng.toFixed(3)}`,
+);
+
+/** mulberry32 — tiny deterministic PRNG (fixed seed => comparable runs). */
+function mulberry32(seed) {
+  let a = seed >>> 0;
+  return () => {
+    a = (a + 0x6d2b79f5) >>> 0;
+    let t = a;
+    t = Math.imul(t ^ (t >>> 15), t | 1);
+    t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
+    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+  };
+}
+
+/* ————— pair sampling: corpus endpoints + quadrant spread ————— */
+
+const corpus = JSON.parse(readFileSync(CORPUS_PATH, "utf8"));
+const gazetteerById = new Map(getEntries().map((e) => [e.id, e]));
+
+const pairs = [];
+let corpusRoutes = 0;
+for (const pair of corpus.pairs) {
+  const dest = gazetteerById.get(pair.destinationId);
+  if (dest === undefined) continue;
+  const origin = snap(graph, { lat: pair.origin.lat, lng: pair.origin.lng });
+  const goal = snap(graph, { lat: dest.lat, lng: dest.lng });
+  if (origin === null || goal === null) continue;
+  pairs.push({ label: `corpus ${pair.pairId}`, from: origin.node, to: goal.node });
+  corpusRoutes += 1;
+}
+
+const midLat = (graph.bbox.minLat + graph.bbox.maxLat) / 2;
+const midLng = (graph.bbox.minLng + graph.bbox.maxLng) / 2;
+const quadrants = [[], [], [], []]; // 0=NW 1=NE 2=SW 3=SE
+for (let n = 0; n < graph.nodeCount; n++) {
+  const q = (graph.lat[n] >= midLat ? 0 : 2) + (graph.lng[n] >= midLng ? 1 : 0);
+  quadrants[q].push(n);
+}
+const rand = mulberry32(SAMPLE_SEED);
+const pick = (q) => quadrants[q][Math.floor(rand() * quadrants[q].length)];
+while (pairs.length < ROUTE_COUNT) {
+  const a = Math.floor(rand() * 4);
+  const b = (a + 1 + Math.floor(rand() * 3)) % 4; // always a DIFFERENT quadrant — cross-city
+  const from = pick(a);
+  const to = pick(b);
+  if (from === to) continue;
+  pairs.push({ label: `quadrant q${a}->q${b}`, from, to });
+}
+console.log(`sample: ${corpusRoutes} corpus-snapped + ${pairs.length - corpusRoutes} quadrant pairs = ${pairs.length} routes`);
+
+/* ————— warm-up (unmeasured, printed) + the measured runs ————— */
+
+function cpuMs(fn) {
+  const t0 = process.hrtime.bigint();
+  const result = fn();
+  const t1 = process.hrtime.bigint();
+  return { ms: Number(t1 - t0) / 1e6, result };
+}
+
+const warm = cpuMs(() => astar(graph, pairs[0].from, pairs[0].to));
+console.log(`warm-up (unmeasured): ${warm.ms.toFixed(3)} ms`);
+
+const samples = [];
+let unreachableProbes = 0;
+let unreachableMs = 0;
+for (const pair of pairs) {
+  const { ms, result } = cpuMs(() => astar(graph, pair.from, pair.to));
+  if (result === null) {
+    // A directed dead-end probe (a snap onto a one-way sink or a small
+    // island): the honest-null degradation path. Reported SEPARATELY — it
+    // is not a routed trip, and mixing it into the route p95 would
+    // misdescribe the budget the /api/route hot path actually needs.
+    unreachableProbes += 1;
+    unreachableMs += ms;
+    console.log(`  ${pair.label}: ${ms.toFixed(3)} ms (unreachable — honest null, D-03)`);
+    continue;
+  }
+  const km = `${(result.distanceM / 1000).toFixed(1)} km / ${(result.seconds / 60).toFixed(1)} min`;
+  console.log(`  ${pair.label}: ${ms.toFixed(3)} ms (${km})`);
+  samples.push(ms);
+}
+console.log(
+  `routed pairs: ${samples.length}/${pairs.length}` +
+    (unreachableProbes > 0
+      ? `; unreachable probes: ${unreachableProbes} (mean ${(unreachableMs / unreachableProbes).toFixed(3)} ms, reported separately)`
+      : ""),
+);
+if (samples.length === 0) fail("no routable pairs in the sample — the graph may be fragmented; rebuild");
+
+samples.sort((a, b) => a - b);
+const idx = Math.min(samples.length - 1, Math.ceil(0.95 * samples.length) - 1);
+const p95 = samples[idx];
+const max = samples[samples.length - 1];
+const mean = samples.reduce((acc, v) => acc + v, 0) / samples.length;
+console.log(`p95: ${p95.toFixed(3)} ms (max ${max.toFixed(3)} ms, mean ${mean.toFixed(3)} ms, n=${samples.length})`);
+
+if (p95 > P95_BUDGET_MS) {
+  console.error(`GATE FAIL: p95 ${p95.toFixed(3)} ms exceeds the ${P95_BUDGET_MS} ms budget (A1) — apply the mitigation ladder: (a) tighten DRIVABLE_CLASSES + rebuild, (b) bidirectional A*, (c) Workers Paid as an explicit fork decision`);
+  process.exit(1);
+}
+console.log(`GATE PASS: p95 ${p95.toFixed(3)} ms <= ${P95_BUDGET_MS} ms budget — A1 retired for this graph`);
+process.exit(0);
@@ -0,0 +1,78 @@
+#!/usr/bin/env node
+/*
+ * upload-road-graph.mjs — put the built road graph on R2 (D-01, fork path).
+ * ---------------------------------------------------------------------------
+ * A MAINTAINER-TIME REPO TOOL — NOT a runtime dependency; nothing in bot/src,
+ * web/src, or routing/src imports it. It shells the wrangler CLI (already the
+ * repo's deploy tool) so a fork needs zero new installs:
+ *
+ *   npx wrangler r2 object put araharah-graphs/kl-roadgraph.v1.bin
+ *       --file routing/data/kl-roadgraph.v1.bin --remote
+ *
+ * THE FORK CONTRACT (docs/ROAD-GRAPH.md is the prose): your graph, YOUR
+ * bucket. Create it first (`npx wrangler r2 bucket create araharah-graphs`
+ * — or your own name, and point bot/wrangler.jsonc's ROAD_GRAPH binding at
+ * it), build the binary with build-road-graph.mjs, then run this. The
+ * Worker side reads the binding, never a bucket name — the name here and in
+ * wrangler.jsonc must simply agree.
+ *
+ * PRE-FLIGHT: the binary must EXIST and clear the enforced 1 MB floor (the
+ * 80 MB ceiling is build-road-graph.mjs's gate — this script re-checks both
+ * cheaply so a stale artifact never uploads silently).
+ *
+ * Usage:
+ *   node routing/scripts/upload-road-graph.mjs
+ *
+ * Exit codes: 0 uploaded; 1 pre-flight failure or wrangler failure.
+ */
+import { execFileSync } from "node:child_process";
+import { existsSync, statSync } from "node:fs";
+import { dirname, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const here = dirname(fileURLToPath(import.meta.url)); // routing/scripts
+const GRAPH_PATH = resolve(here, "..", "data", "kl-roadgraph.v1.bin");
+
+/** Must agree with bot/wrangler.jsonc's ROAD_GRAPH binding bucket_name. */
+const BUCKET = "araharah-graphs";
+/** Must agree with worker-router.ts's GRAPH_KEY. */
+const KEY = "kl-roadgraph.v1.bin";
+/** The enforced floor — an at/below-floor file is a broken build, never an upload. */
+const MIN_BINARY_BYTES = 1 * 1024 * 1024;
+const MAX_BINARY_BYTES = 80 * 1024 * 1024;
+
+function fail(message) {
+  console.error(`upload-road-graph: ${message}`);
+  process.exit(1);
+}
+
+if (!existsSync(GRAPH_PATH)) {
+  fail(`no graph at ${GRAPH_PATH} — build it first: node routing/scripts/build-road-graph.mjs`);
+}
+const bytes = statSync(GRAPH_PATH).size;
+if (bytes <= MIN_BINARY_BYTES || bytes > MAX_BINARY_BYTES) {
+  fail(
+    `${GRAPH_PATH} is ${bytes} bytes — outside the enforced 1-80 MB envelope (D-01). ` +
+      `Rebuild and heed the stats gate: node routing/scripts/build-road-graph.mjs`,
+  );
+}
+console.log(`uploading ${GRAPH_PATH} (${(bytes / (1024 * 1024)).toFixed(1)} MB) -> r2://${BUCKET}/${KEY}`);
+
+try {
+  execFileSync(
+    "npx",
+    ["wrangler", "r2", "object", "put", `${BUCKET}/${KEY}`, "--file", GRAPH_PATH, "--remote", "--content-type", "application/octet-stream"],
+    { stdio: "inherit" },
+  );
+} catch (err) {
+  fail(
+    `wrangler failed (${err.status ?? "no status"}). If the bucket does not exist yet: ` +
+      `npx wrangler r2 bucket create ${BUCKET} — and if R2 is not enabled on the account, ` +
+      `activate it once in the Cloudflare dashboard (R2 -> Get started).`,
+  );
+}
+
+console.log(`uploaded r2://${BUCKET}/${KEY}`);
+console.log("next: npm run dev -w bot   # /api/route loads it through the ROAD_GRAPH binding (memoized per isolate)");
+console.log(`verify: npx wrangler r2 object get ${BUCKET}/${KEY} --file /tmp/opencode/graph-roundtrip.bin --remote && node routing/scripts/build-road-graph.mjs --check /tmp/opencode/graph-roundtrip.bin`);
+process.exit(0);
@@ -1,20 +1,17 @@
 /*
- * astar.ts — typed-array A* over the CSR graph + turn-step derivation (D-01).
+ * astar.ts — typed-array BIDIRECTIONAL A* over the CSR graph + turn-step
+ * derivation (D-01; bidirectional per 06-04's A1 ladder step b).
 * ----------------------------------------------------------------------------
 * The engine-A router core: routeAstar finds the minimum-seconds path
- * between two graph nodes with an ALLOCATION-FREE hot loop — open set is a
- * binary heap of node indices over preallocated typed arrays, g-scores and
- * the closed set are per-node typed arrays. No Map, no JS objects per node
- * (RESEARCH Pattern 2 + Anti-Patterns; the 10 ms free-plan CPU budget is
- * the design constraint, A1's equivalence sweep is the correctness gate).
- *
- * Heuristic: haversine(node, goal) / (maxSpeedKmh / 3.6) — the aerial
- * distance divided by the graph's maximum speed can never overestimate the
- * remaining travel time (every edge's seconds = meters / speed with speed
- * <= maxSpeedKmh), so it is admissible AND consistent; settling the goal
- * off the heap is therefore provably optimal (A1 proves it exhaustively on
- * the fixture). The heuristic is computed on demand and cached per node in
- * a Float64Array — no object is constructed in the search loop.
+ * between two graph nodes. The search is BIDIRECTIONAL (BH, Ikeda
+ * potentials — see routeAstar's doc) because the free-plan 10 ms CPU budget
+ * is the design constraint and the measured unidirectional p95 on the real
+ * KL graph was 3-5x over it. The hot loops remain allocation-free: binary
+ * heaps of node indices over preallocated typed arrays, typed-array
+ * distances/closed sets/chains, lazy on-demand potentials, no Map, no
+ * objects per node. Optimality is not presumed — astar.test.mjs A1
+ * exhaustively proves equivalence to brute-force Dijkstra on the fixture
+ * (625 pairs), and the oneway/unreachable laws have dedicated cases.
 *
 * Traversal law (shared with the tests' brute-force Dijkstra): an edge with
 * edgeFlags bit0 set ("oneway-reverse" — see graph.ts) is NEVER relaxed.
@@ -91,6 +88,11 @@ class NodeHeap {
    this.nodes[i] = node;
  }

+  /** The min key without popping; Infinity when empty (the BH stop rule reads this). */
+  peekKey(): number {
+    return this.size === 0 ? Number.POSITIVE_INFINITY : this.keys[0]!;
+  }
+
  /** Returns the min-key node, or -1 when empty. Lazy deletion: stale
   *  entries are skipped by the closed-set check in routeAstar. */
  pop(): number {
@@ -127,12 +129,92 @@ class NodeHeap {
  }
 }

-/* ————— A* ————— */
+/* ————— A* — bidirectional (BH, Ikeda potentials) ————— */
+
+/** Inline haversine from a graph node to a fixed (lat, lng), in METERS. */
+function metersTo(graph: RoadGraph, v: number, lat2: number, lng2: number): number {
+  const lat1 = graph.lat[v]! * DEG_TO_RAD;
+  const lat2r = lat2 * DEG_TO_RAD;
+  const dLat = lat2r - lat1;
+  const dLng = (lng2 - graph.lng[v]!) * DEG_TO_RAD;
+  const sinLat = Math.sin(dLat / 2);
+  const sinLng = Math.sin(dLng / 2);
+  const h = sinLat * sinLat + Math.cos(lat1) * Math.cos(lat2r) * sinLng * sinLng;
+  return 2 * EARTH_RADIUS_M * Math.asin(Math.min(1, Math.sqrt(h)));
+}
+
+/* ————— reverse adjacency (the backward search's in-edge scan) ————— */
+
+/**
+ * The reverse CSR (in-edges per node), built ONCE per RoadGraph and
+ * memoized in a module-scope WeakMap — the snap-grid LAW 1 pattern. The
+ * backward search cannot iterate a node's in-edges out of a source-grouped
+ * CSR (that was the 06-04 GREEN bug the A1/A2 gates caught: out-edges read
+ * as in-edges fabricate phantom arcs and traverse oneway mirrors); this
+ * index makes them addressable without touching the pinned binary layout.
+ * One-time build is O(V+E) per isolate, paid by the first route (the CPU
+ * gate's warm-up covers it), amortized across the isolate's requests.
+ */
+interface ReverseAdj {
+  /** rowStart[u]..rowStart[u+1] index u's IN-edges inside targets/edgeIds. */
+  rowStart: Uint32Array;
+  /** The in-edge's SOURCE node (v, for an edge v -> u). */
+  targets: Uint32Array;
+  /** The edge's index in the forward CSR (weights/flags/seconds lookup). */
+  edgeIds: Uint32Array;
+}
+
+const reverseGraphs = new WeakMap<RoadGraph, ReverseAdj>();
+
+function reverseFor(graph: RoadGraph): ReverseAdj {
+  const memoized = reverseGraphs.get(graph);
+  if (memoized !== undefined) return memoized;
+  const n = graph.nodeCount;
+  const edgeCount = graph.edgeCount;
+  const inDegree = new Uint32Array(n + 1);
+  for (let e = 0; e < edgeCount; e++) inDegree[graph.edgeTarget[e]! + 1] = inDegree[graph.edgeTarget[e]! + 1]! + 1;
+  for (let i = 0; i < n; i++) inDegree[i + 1] = inDegree[i + 1]! + inDegree[i]!;
+  const targets = new Uint32Array(edgeCount);
+  const edgeIds = new Uint32Array(edgeCount);
+  const cursor = inDegree.slice(0, n);
+  for (let u = 0; u < n; u++) {
+    for (let e = graph.edgeStart[u]!; e < graph.edgeStart[u + 1]!; e++) {
+      const v = graph.edgeTarget[e]!; // the edge u -> v is an IN-edge of v
+      const pos = cursor[v]!;
+      cursor[v] = pos + 1;
+      targets[pos] = u;
+      edgeIds[pos] = e;
+    }
+  }
+  const adj: ReverseAdj = { rowStart: inDegree, targets, edgeIds };
+  reverseGraphs.set(graph, adj);
+  return adj;
+}

 /**
 * Minimum-seconds path origin -> goal over the graph, or null when the pair
 * is unreachable (the honest miss). Exhaustively proven equal to
 * brute-force Dijkstra on the committed mini-graph (astar.test.mjs A1).
+ *
+ * BIDIRECTIONAL (A1 ladder step b, 06-04): the free-plan 10 ms CPU ceiling
+ * demands it — measured on the real 311k-node KL graph, the unidirectional
+ * search's weak max-speed heuristic balloons on 20-30 km routes (p95 38 ms).
+ * BH construction (Ikeda et al.): with directional heuristics
+ * h_f(v)=hav(v,goal)/maxSpeed and h_b(v)=hav(v,origin)/maxSpeed (each
+ * consistent on its own search graph) and the opposite potentials
+ *   p_f(v) = (h_f(v) - h_b(v))/2,  p_b(v) = -p_f(v),
+ * the reductions
+ *   forward, edge u->v:   c + p_f(u) - p_f(v)
+ *   backward, in-edge v->u of settled u: c + p_b(u) - p_b(v)
+ * are NON-NEGATIVE (each feasibility is the sum of the two consistencies,
+ * each <= c), and the meet keys satisfy
+ *   d_f(v) + d_b(v) = real(o->g through v) - p_f(o) + p_f(g)
+ * — a v-independent constant — so stopping when top_f + top_b >= mu (the
+ * best meeting cost seen) settles the goal PROVABLY optimally, at roughly
+ * half the explored radius per side. Alternation balance is a work knob,
+ * not a correctness knob (the stop rule carries optimality); A1's
+ * exhaustive 625-pair Dijkstra-equivalence sweep is the standing proof,
+ * re-run on every pass.
 */
 export function routeAstar(graph: RoadGraph, originNode: number, goalNode: number): AstarResult | null {
  const n = graph.nodeCount;
@@ -144,72 +226,143 @@ export function routeAstar(graph: RoadGraph, originNode: number, goalNode: numbe
  const heuristicScale = maxSpeedMps > 0 ? 1 / maxSpeedMps : 1;
  const goalLat = graph.lat[goalNode]!;
  const goalLng = graph.lng[goalNode]!;
+  const origLat = graph.lat[originNode]!;
+  const origLng = graph.lng[originNode]!;

-  const gScore = new Float64Array(n).fill(Number.POSITIVE_INFINITY);
-  const cameFrom = new Int32Array(n).fill(-1);
-  const closed = new Uint8Array(n);
-  const hCache = new Float64Array(n).fill(Number.NaN); // NaN = not computed yet
-  const heap = new NodeHeap();
-
-  // Inline haversine vs the goal, cached per node — zero allocations, and
-  // only explored nodes ever pay for it. Admissible: aerial distance at
-  // max speed upper-bounds nothing — it LOWER-bounds remaining seconds.
-  const heuristic = (node: number): number => {
-    const cached = hCache[node]!;
-    if (!Number.isNaN(cached)) return cached;
-    const lat1 = graph.lat[node]! * DEG_TO_RAD;
-    const lat2 = goalLat * DEG_TO_RAD;
-    const dLat = lat2 - lat1;
-    const dLng = (goalLng - graph.lng[node]!) * DEG_TO_RAD;
-    const sinLat = Math.sin(dLat / 2);
-    const sinLng = Math.sin(dLng / 2);
-    const h = sinLat * sinLat + Math.cos(lat1) * Math.cos(lat2) * sinLng * sinLng;
-    const meters = 2 * EARTH_RADIUS_M * Math.asin(Math.min(1, Math.sqrt(h)));
-    const seconds = meters * heuristicScale;
-    hCache[node] = seconds;
-    return seconds;
-  };
-
-  gScore[originNode] = 0;
-  heap.push(heuristic(originNode), originNode);
-
-  while (heap.size > 0) {
-    const u = heap.pop();
-    if (u < 0) break;
-    if (closed[u]! !== 0) continue; // lazy deletion
-    closed[u] = 1;
-    if (u === goalNode) {
-      // Reconstruct (allocation here is fine — the hot loop is over).
-      const path: number[] = [u];
-      let prev = cameFrom[u]!;
-      while (prev >= 0) {
-        path.push(prev);
-        prev = cameFrom[prev]!;
-      }
-      path.reverse();
-      let distanceM = 0;
-      for (let i = 1; i < path.length; i++) {
-        distanceM += haversineM(
-          { lat: graph.lat[path[i - 1]!]!, lng: graph.lng[path[i - 1]!]! },
-          { lat: graph.lat[path[i]!]!, lng: graph.lng[path[i]!]! },
-        );
-      }
-      return { nodes: path, seconds: gScore[goalNode]!, distanceM };
+  // Directional heuristics + opposite potentials, lazy per node — only
+  // explored nodes ever pay, and the hot loops stay allocation-free.
+  const hfCache = new Float64Array(n).fill(Number.NaN); // hav(v, goal) * scale
+  const hbCache = new Float64Array(n).fill(Number.NaN); // hav(v, origin) * scale
+  const pf = new Float64Array(n); // p_f(v) = (h_f - h_b)/2; p_b = -p_f — valid once both caches are set
+  function potential(v: number): number {
+    let hf = hfCache[v]!;
+    if (Number.isNaN(hf)) {
+      hf = metersTo(graph, v, goalLat, goalLng) * heuristicScale;
+      hfCache[v] = hf;
    }
-    const base = gScore[u]!;
-    for (let e = graph.edgeStart[u]!; e < graph.edgeStart[u + 1]!; e++) {
-      if ((graph.edgeFlags[e]! & 1) !== 0) continue; // oneway-reverse: never traversed
-      const v = graph.edgeTarget[e]!;
-      if (closed[v]! !== 0) continue;
-      const candidate = base + graph.edgeSeconds[e]!;
-      if (candidate < gScore[v]!) {
-        gScore[v] = candidate;
-        cameFrom[v] = u;
-        heap.push(candidate + heuristic(v), v);
+    let hb = hbCache[v]!;
+    if (Number.isNaN(hb)) {
+      hb = metersTo(graph, v, origLat, origLng) * heuristicScale;
+      hbCache[v] = hb;
+    }
+    const value = (hf - hb) / 2;
+    pf[v] = value;
+    return value;
+  }
+
+  // Reduced distances (BH keys), chain arrays, closed sets, one heap per side.
+  const df = new Float64Array(n).fill(Number.POSITIVE_INFINITY); // reduced origin->v
+  const db = new Float64Array(n).fill(Number.POSITIVE_INFINITY); // reduced v->goal
+  const fPrev = new Int32Array(n).fill(-1); // predecessor on the origin->v chain
+  const bNext = new Int32Array(n).fill(-1); // successor on the v->goal chain
+  const fClosed = new Uint8Array(n);
+  const bClosed = new Uint8Array(n);
+  const fHeap = new NodeHeap();
+  const bHeap = new NodeHeap();
+
+  df[originNode] = 0;
+  potential(originNode); // pf[o] is needed by the first forward relaxations
+  fHeap.push(0, originNode); // key = the REDUCED distance itself (the heuristic lives in the reduction)
+  db[goalNode] = 0;
+  potential(goalNode); // p_b(g) likewise for the first backward relaxations
+  bHeap.push(0, goalNode);
+
+  let mu = Number.POSITIVE_INFINITY; // best meeting key sum (real + const)
+  let meetFrom = -1; // bridge edge meetFrom -> meetTo (direction of travel)
+  let meetTo = -1;
+
+  while (fHeap.size > 0 && bHeap.size > 0) {
+    // THE BH STOP RULE: with consistent potentials, no future meeting can
+    // beat mu once both frontiers' minima sum past it.
+    if (fHeap.peekKey() + bHeap.peekKey() >= mu) break;
+    // BALANCED ALTERNATION: expand the side with the smaller frontier.
+    // (Measured 06-04: comparing raw tops starves the backward side — its
+    // keys start near the full route cost while the forward side's start
+    // near zero, so `top_f <= top_b` ran the forward search almost alone
+    // (19501:3 settles) and landed 4x SLOWER than unidirectional. Heap
+    // size keeps both rings growing; correctness lives entirely in the
+    // stop rule — alternation order is a work-balancing knob only.)
+    const expandForward = fHeap.size <= bHeap.size;
+    const u = (expandForward ? fHeap : bHeap).pop()!;
+    if (expandForward ? fClosed[u]! !== 0 : bClosed[u]! !== 0) continue; // lazy deletion
+    if (expandForward) fClosed[u] = 1;
+    else bClosed[u] = 1;
+
+    if (expandForward) {
+      const du = df[u]!;
+      const pfu = pf[u]!;
+      for (let e = graph.edgeStart[u]!; e < graph.edgeStart[u + 1]!; e++) {
+        if ((graph.edgeFlags[e]! & 1) !== 0) continue; // oneway-reverse: never traversed
+        const v = graph.edgeTarget[e]!;
+        const pv = potential(v);
+        const candidate = du + graph.edgeSeconds[e]! + pfu - pv;
+        if (candidate < df[v]!) {
+          df[v] = candidate;
+          fPrev[v] = u;
+          fHeap.push(candidate, v);
+        }
+        // Meet probe: v already reached backward? (candidate uses v's BEST d_b)
+        if (db[v]! < Number.POSITIVE_INFINITY) {
+          const meet = candidate + db[v]!;
+          if (meet < mu) {
+            mu = meet;
+            meetFrom = u;
+            meetTo = v;
+          }
+        }
+      }
+    } else {
+      const rev = reverseFor(graph);
+      const du = db[u]!;
+      const pfu = pf[u]!;
+      const end = rev.rowStart[u + 1]!;
+      for (let r = rev.rowStart[u]!; r < end; r++) {
+        const e = rev.edgeIds[r]!; // the edge v -> u
+        if ((graph.edgeFlags[e]! & 1) !== 0) continue; // oneway-reverse: never traversed
+        const v = rev.targets[r]!;
+        const pvv = potential(v);
+        const candidate = du + graph.edgeSeconds[e]! - pfu + pvv;
+        if (candidate < db[v]!) {
+          db[v] = candidate;
+          bNext[v] = u;
+          bHeap.push(candidate, v);
+        }
+        if (df[v]! < Number.POSITIVE_INFINITY) {
+          const meet = candidate + df[v]!;
+          if (meet < mu) {
+            mu = meet;
+            meetFrom = v; // the path travels v -> u here
+            meetTo = u;
+          }
+        }
      }
    }
  }
-  return null; // unreachable — honest miss
+
+  if (meetFrom < 0) return null; // never met — unreachable (honest miss)
+
+  // Reconstruct: origin ->(fPrev)-> meetFrom -[bridge]-> meetTo ->(bNext)-> goal.
+  const fPart: number[] = [];
+  for (let x = meetFrom; x >= 0; x = fPrev[x]!) fPart.push(x);
+  fPart.reverse();
+  const bPart: number[] = [];
+  for (let y = meetTo; y >= 0; y = bNext[y]!) bPart.push(y);
+  const path = fPart.concat(bPart);
+
+  // REAL costs recomputed along the node path (exact; no reduced-cost
+  // arithmetic leaks into the returned seconds).
+  let seconds = 0;
+  let distanceM = 0;
+  for (let i = 1; i < path.length; i++) {
+    const a = path[i - 1]!;
+    const b = path[i]!;
+    const from = { lat: graph.lat[a]!, lng: graph.lng[a]! };
+    const to = { lat: graph.lat[b]!, lng: graph.lng[b]! };
+    distanceM += haversineM(from, to);
+    const edge = findTraversableEdge(graph, a, b);
+    seconds += edge >= 0 ? graph.edgeSeconds[edge]! : 0; // -1 only on a corrupt chain — loud in deriveSteps
+  }
+  return { nodes: path, seconds, distanceM };
 }

 /* ————— turn classification (the one authority; plan 07 imports this) ————— */