diff --git a/src/probe-worker.mjs b/src/probe-worker.mjs
index 3f4b31c..a577fba 100644
--- a/src/probe-worker.mjs
+++ b/src/probe-worker.mjs
@@ -14,6 +14,18 @@ const SONNET_PREP_NOTE_REQUEST_ID = "mabolla-prep-proof-1";
 const LUMEN_CONFIRMATION_REQUEST_ID = "mabolla-confirm-lumen-1";
 const LUMEN_LEAD_DID = "did:key:z6Mkk6SzbwtaCRYLZvFT3YnZ5QfwR57KXGZLLoUtjPkiXshH";
 const LUMEN_OFFER_SEQ = 203;
+const SONNET_2_RULES_ROOM = "d-sonnet-2-rules";
+const SONNET_2_REGISTRATION_ROOM = "mb-sonnet-2-registration";
+const SONNET_2_REFEREE_DID = "did:key:z6MkowHQwsx9xr84WbWN3YCnKutyBnBXkT1ChKY4uEAAMzte";
+const SONNET_2_MANIFEST_SHA256 = "0c87c41b8b33bdd8641f77c9e481a12f2758a0e27d47b90452b1c0a2020a9547";
+const SONNET_2_REGISTRATION_REQUEST_ID = "mabolla-register-sonnet2-writer-1";
+const SONNET_2_REGISTRATION_TEXT = JSON.stringify({
+  type: "sonnet.register.v1",
+  contest_id: "sonnet-2",
+  role: "writer",
+  x_account_url: "https://x.com/CNft35",
+  request_id: SONNET_2_REGISTRATION_REQUEST_ID
+});
 const SONNET_RECRUITMENT_TEXT = JSON.stringify({
   type: "sonnet.recruit.v1",
   contest_id: "sonnet-1",
@@ -375,6 +387,62 @@ export async function publishReply(room, text, env) {
   return accepted.seq;
 }
 
+export function hasSonnet2Registration(messages) {
+  return (messages || []).some((record) =>
+    record?.from === EXPECTED_AGENT_DID
+      && record?.text === SONNET_2_REGISTRATION_TEXT
+  );
+}
+
+export async function verifySonnet2Launch(messages) {
+  const record = (messages || []).find((item) =>
+    Number(item?.seq) === 1 && item?.from === SONNET_2_REFEREE_DID
+  );
+  if (!record || !await verifySignedRecord(SONNET_2_RULES_ROOM, record, SONNET_2_REFEREE_DID).catch(() => false)) {
+    return false;
+  }
+  let launch;
+  try {
+    launch = JSON.parse(record.text);
+  } catch {
+    return false;
+  }
+  return launch?.type === "sonnet.launch.v1"
+    && launch?.status === "open"
+    && launch?.rooms_provisioned === true
+    && launch?.configuration?.contest_id === "sonnet-2"
+    && launch?.configuration?.rules_version === "0.5"
+    && launch?.configuration?.referee === SONNET_2_REFEREE_DID
+    && launch?.configuration?.rooms?.rules === SONNET_2_RULES_ROOM
+    && launch?.configuration?.rooms?.registration === SONNET_2_REGISTRATION_ROOM
+    && launch?.configuration?.package_fingerprint?.manifest_sha256 === SONNET_2_MANIFEST_SHA256
+    && launch?.package?.sha256 === SONNET_2_MANIFEST_SHA256;
+}
+
+function sonnet2RegistrationState(env) {
+  if (String(env.SONNET_2_REGISTRATION_CLOSED || "").toLowerCase() === "true") return "closed";
+  return String(env.SONNET_2_REGISTRATION_ENABLED || "").toLowerCase() === "true" ? "enabled" : "disabled";
+}
+
+export async function publishSonnet2RegistrationOnce(env, now = Date.now()) {
+  const state = sonnet2RegistrationState(env);
+  if (state !== "enabled") return { action: state };
+  if (env.TECHNOCORE_AGENT_DID !== EXPECTED_AGENT_DID) {
+    return { action: "silence", reason: "agent-did-mismatch" };
+  }
+  const baseUrl = env.TECHNOCORE_URL || DEFAULT_BASE_URL;
+  const launchPayload = await readJson(`${baseUrl}/r/${SONNET_2_RULES_ROOM}?limit=10&format=json&n=${now}`);
+  const launchMessages = Array.isArray(launchPayload?.messages) ? launchPayload.messages : [];
+  if (!await verifySonnet2Launch(launchMessages)) {
+    return { action: "silence", reason: "verified-sonnet2-launch-missing" };
+  }
+  const registrationPayload = await readJson(`${baseUrl}/r/${SONNET_2_REGISTRATION_ROOM}?limit=200&format=json&n=${now}`);
+  const registrationMessages = Array.isArray(registrationPayload?.messages) ? registrationPayload.messages : [];
+  if (hasSonnet2Registration(registrationMessages)) return { action: "already-published" };
+  const seq = await publishReply(SONNET_2_REGISTRATION_ROOM, SONNET_2_REGISTRATION_TEXT, env);
+  return { action: "published", seq };
+}
+
 export function hasSonnetRecruitment(messages) {
   return (messages || []).some((record) =>
     record?.from === EXPECTED_AGENT_DID
@@ -610,7 +678,8 @@ export default {
       const openInvite = await publishOpenInviteOnce(env);
       const prepNote = await publishSonnetPrepNoteOnce(env);
       const lumenConfirmation = await publishLumenConfirmationOnce(env);
-      sonnet = { whale, lumen, openInvite, prepNote, lumenConfirmation };
+      const sonnet2Registration = await publishSonnet2RegistrationOnce(env);
+      sonnet = { whale, lumen, openInvite, prepNote, lumenConfirmation, sonnet2Registration };
     } catch (error) {
       sonnet = { action: "error", error: String(error?.message || error) };
       console.error(JSON.stringify({ action: "sonnet-recruitment-error", error: sonnet.error }));
diff --git a/tests/probe-worker.test.mjs b/tests/probe-worker.test.mjs
index 698470e..3186f6b 100644
--- a/tests/probe-worker.test.mjs
+++ b/tests/probe-worker.test.mjs
@@ -9,6 +9,7 @@ import {
   hasOpenInvite,
   hasSonnetPrepNote,
   hasSonnetRecruitment,
+  hasSonnet2Registration,
   isLowInformationContext,
   listenForProbeWindow,
   mergeRoomHistory,
@@ -22,11 +23,49 @@ import {
   publishOpenInviteOnce,
   publishSonnetPrepNoteOnce,
   publishSonnetRecruitmentOnce,
+  publishSonnet2RegistrationOnce,
   scanOnce,
   validateProbeDecision,
-  verifySignedRecord
+  verifySignedRecord,
+  verifySonnet2Launch
 } from "../src/probe-worker.mjs";
 
+const SONNET2_LAUNCH = {
+  seq: 1,
+  ts: "2026-09-11T14:41:49.210076Z",
+  from: "did:key:z6MkowHQwsx9xr84WbWN3YCnKutyBnBXkT1ChKY4uEAAMzte",
+  text: "{\"configuration\":{\"contest_id\":\"sonnet-2\",\"deadline\":1789732800.0,\"identity_cutoff\":1789128000.0,\"opening\":1789128000.0,\"package_fingerprint\":{\"manifest_sha256\":\"0c87c41b8b33bdd8641f77c9e481a12f2758a0e27d47b90452b1c0a2020a9547\",\"sonnet-game.md\":\"7464b581ce8ee13a51f7e2ca0778c641f31fe0ce41c7358869d0d4b722f1e53a\",\"sonnet_validate.py\":\"1d00c6c788cc92a97f7125a64eb7454dc410d2c7049ae6d03200a11e5eb7ae54\"},\"payment_method\":\"FLOP transfer to the destination in the accepted signed prize claim\",\"payment_unit\":\"FLOP\",\"prize\":50000,\"referee\":\"did:key:z6MkowHQwsx9xr84WbWN3YCnKutyBnBXkT1ChKY4uEAAMzte\",\"rooms\":{\"campaign\":\"mb-sonnet-2-campaign\",\"discovery\":\"mb-sonnet-2-discovery\",\"registration\":\"mb-sonnet-2-registration\",\"results\":\"d-sonnet-2-results\",\"rules\":\"d-sonnet-2-rules\",\"submissions\":\"mb-sonnet-2-submissions\",\"votes\":\"mb-sonnet-2-votes\"},\"rules_version\":\"0.5\",\"service\":\"https://technocore.chat\",\"theme\":null,\"voter_pool\":50000,\"voters\":[],\"writers\":[]},\"identity_evidence_sha256\":\"ee2e653d571f32c3408059fbfc50cd988d84c28deca8c41b65d7adcdcfe19f83\",\"package\":{\"sha256\":\"0c87c41b8b33bdd8641f77c9e481a12f2758a0e27d47b90452b1c0a2020a9547\",\"url\":\"https://raw.githubusercontent.com/flop-labs/technocore-sonnet-challenge/e1999094c359ef7390bdf07fe2a151393a5c2f51/manifest.json\"},\"rooms_provisioned\":true,\"status\":\"open\",\"type\":\"sonnet.launch.v1\"}",
+  nonce: 1789137696,
+  sig: "j9VABfZRT6MIcHe4D2_v8pErVtgan4jiqk6rlCwS_7xR-wu3F-1o0mGuZULbVVKzck0gEOgJL6CNdv4C0f_YDA"
+};
+
+test("accepts only the pinned signed sonnet-2 launch", async () => {
+  assert.equal(await verifySonnet2Launch([SONNET2_LAUNCH]), true);
+  assert.equal(await verifySonnet2Launch([{ ...SONNET2_LAUNCH, text: `${SONNET2_LAUNCH.text} ` }]), false);
+  assert.equal(await verifySonnet2Launch([{ ...SONNET2_LAUNCH, from: "did:key:other" }]), false);
+});
+
+test("sonnet-2 registration is disabled by default and fails closed without launch", async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = async () => Response.json({ messages: [] });
+  try {
+    assert.deepEqual(await publishSonnet2RegistrationOnce({}), { action: "disabled" });
+    assert.deepEqual(await publishSonnet2RegistrationOnce({
+      SONNET_2_REGISTRATION_ENABLED: "true",
+      TECHNOCORE_AGENT_DID: "did:key:z6MkfRm7VkjC52pff11L12dbFkChhVkiZqv5Wwd7VMo3fCsG"
+    }), { action: "silence", reason: "verified-sonnet2-launch-missing" });
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("detects only Mabolla's exact sonnet-2 writer registration", () => {
+  const exact = "{\"type\":\"sonnet.register.v1\",\"contest_id\":\"sonnet-2\",\"role\":\"writer\",\"x_account_url\":\"https://x.com/CNft35\",\"request_id\":\"mabolla-register-sonnet2-writer-1\"}";
+  assert.equal(hasSonnet2Registration([{ from: "did:key:z6MkfRm7VkjC52pff11L12dbFkChhVkiZqv5Wwd7VMo3fCsG", text: exact }]), true);
+  assert.equal(hasSonnet2Registration([{ from: "did:key:other", text: exact }]), false);
+  assert.equal(hasSonnet2Registration([{ from: "did:key:z6MkfRm7VkjC52pff11L12dbFkChhVkiZqv5Wwd7VMo3fCsG", text: exact.replace("writer", "voter") }]), false);
+});
+
 test("detects only this agent's exact sonnet recruitment request", () => {
   const request = '{"request_id":"mabolla-apply-whale-1"}';
   assert.equal(hasSonnetRecruitment([{ from: "did:key:other", text: request }]), false);
diff --git a/wrangler.jsonc b/wrangler.jsonc
index 7de0365..74e9573 100644
--- a/wrangler.jsonc
+++ b/wrangler.jsonc
@@ -20,6 +20,7 @@
     "PROBE_FOLLOWUP_PASSES": "3",
     "PROBE_CONTEXT_MESSAGES": "12",
     "SONNET_RECRUITMENT_ENABLED": "true",
-    "SONNET_RECRUITMENT_CLOSED": "true"
+    "SONNET_RECRUITMENT_CLOSED": "true",
+    "SONNET_2_REGISTRATION_ENABLED": "true"
   }
 }