diff --git a/deploy/mainnet/openrouter-reseller.config.json b/deploy/mainnet/openrouter-reseller.config.json
index 401a167..f95f56d 100644
--- a/deploy/mainnet/openrouter-reseller.config.json
+++ b/deploy/mainnet/openrouter-reseller.config.json
@@ -2,7 +2,7 @@
   "networkId": 1,
   "ogmiosUrl": "https://ogmios.vector.mainnet.apexfusion.org",
   "endpointUrl": "https://mp-suppliers-openrouter-reseller.vector.apexfusion.org",
-  "marketplaceModel": "vector/deepseek-v4-flash-spot",
+  "marketplaceModel": "deepseek/deepseek-v4-flash",
   "openRouterModel": "deepseek/deepseek-v4-flash",
   "maxInputTokens": 8192,
   "maxOutputTokens": 512,
diff --git a/gateway/src/cli/reseller-demo.ts b/gateway/src/cli/reseller-demo.ts
index 0d8dc2b..5044585 100644
--- a/gateway/src/cli/reseller-demo.ts
+++ b/gateway/src/cli/reseller-demo.ts
@@ -62,6 +62,23 @@ export async function runResellerDemo(
   const controller = new AbortController();
   const timer = setTimeout(() => controller.abort(), options.timeoutMs);
   try {
+    const sellerResponse = await fetch(`${options.dashboardUrl}/api/status`, {
+      cache: "no-store",
+      signal: controller.signal,
+    });
+    const sellerBody = await sellerResponse.json().catch(() => null) as
+      | Record<string, unknown>
+      | null;
+    if (!sellerResponse.ok) {
+      throw new Error(
+        `seller status returned HTTP ${sellerResponse.status}`,
+      );
+    }
+    const supplierPkh = sellerBody?.supplier_pkh;
+    if (typeof supplierPkh !== "string" || !/^[0-9a-fA-F]{56}$/.test(supplierPkh)) {
+      throw new Error("seller status omitted a valid supplier_pkh");
+    }
+
     const response = await fetch(
       `${options.gatewayUrl}/openai/v1/chat/completions`,
       {
@@ -76,6 +93,7 @@ export async function runResellerDemo(
           max_tokens: options.maxTokens,
           stream: false,
           public_preview: true,
+          x_vector: { supplier_pkh: supplierPkh },
         }),
         signal: controller.signal,
       },
@@ -101,6 +119,7 @@ export async function runResellerDemo(
       completion_id: body?.id ?? null,
       escrow_ref: escrowRef,
       model: body?.model ?? options.model,
+      supplier_pkh: supplierPkh,
       upstream_cost_usd: job.upstream_cost_usd,
       ap3x_payout: job.ap3x_payout,
       dashboard_url: options.dashboardUrl,
diff --git a/gateway/src/openai/chatCompletions.ts b/gateway/src/openai/chatCompletions.ts
index e6ae98b..7eb2306 100644
--- a/gateway/src/openai/chatCompletions.ts
+++ b/gateway/src/openai/chatCompletions.ts
@@ -96,6 +96,7 @@ async function runOneShot(
     indexerUrl: config.indexerUrl,
     model: parsed.model,
     capabilityId: CAPABILITY,
+    supplierPkh: parsed.supplierPkh,
     fetchFn,
   });
   if (candidates.length === 0) {
diff --git a/gateway/src/openai/validate.ts b/gateway/src/openai/validate.ts
index be27fc8..338086b 100644
--- a/gateway/src/openai/validate.ts
+++ b/gateway/src/openai/validate.ts
@@ -13,6 +13,7 @@ export interface ParsedChatRequest {
   tools?: unknown[];
   toolChoice?: unknown;
   publicPreview: boolean;
+  supplierPkh?: string;
 }
 
 const ROLES = new Set(["system", "user", "assistant"]);
@@ -92,6 +93,38 @@ export function parseChatRequest(body: unknown, opts?: { allowTools?: boolean })
   }
   const publicPreview = b.public_preview === true;
 
+  let supplierPkh: string | undefined;
+  if (b.x_vector !== undefined) {
+    if (
+      typeof b.x_vector !== "object" ||
+      b.x_vector === null ||
+      Array.isArray(b.x_vector)
+    ) {
+      throw badRequest("invalid_x_vector", "`x_vector` must be an object");
+    }
+    const requested = (b.x_vector as Record<string, unknown>).supplier_pkh;
+    if (
+      requested !== undefined &&
+      (typeof requested !== "string" || !/^[0-9a-fA-F]{56}$/.test(requested))
+    ) {
+      throw badRequest(
+        "invalid_supplier_pkh",
+        "`x_vector.supplier_pkh` must be a 28-byte hex payment-key hash",
+      );
+    }
+    if (typeof requested === "string") supplierPkh = requested.toLowerCase();
+  }
+
+
   const stream = b.stream === true;
-  return { model, messages, maxTokens, stream, tools, toolChoice, publicPreview };
+  return {
+    model,
+    messages,
+    maxTokens,
+    stream,
+    tools,
+    toolChoice,
+    publicPreview,
+    supplierPkh,
+  };
 }
diff --git a/gateway/src/routing/selectSupplier.ts b/gateway/src/routing/selectSupplier.ts
index 39e2ab5..c1708b8 100644
--- a/gateway/src/routing/selectSupplier.ts
+++ b/gateway/src/routing/selectSupplier.ts
@@ -58,6 +58,8 @@ export interface SelectSupplierOpts {
    * already pins the model). */
   model: string;
   capabilityId: string;
+  /** Optional exact seller identity pin for deterministic agent routing. */
+  supplierPkh?: string;
   fetchFn?: typeof globalThis.fetch;
   /** supplier_pkhs eligible regardless of polled status — used after the demo
    * executor frees a supplier the indexer poller (~20 s cadence) still reports
@@ -86,6 +88,9 @@ export async function selectCandidates(opts: SelectSupplierOpts): Promise<Suppli
   for (const raw of body as SupplierView[]) {
     if (raw.capability_id !== opts.capabilityId) continue;
     if (opts.model !== "" && raw.model !== opts.model) continue;
+    if (opts.supplierPkh !== undefined && raw.supplier_pkh !== opts.supplierPkh) {
+      continue;
+    }
     if (raw.advert_status !== "Active") continue;
     if (raw.status !== "free" && raw.status !== "unknown" && !opts.ignoreStatusFor?.has(raw.supplier_pkh)) {
       continue;
diff --git a/gateway/test/unit.test.ts b/gateway/test/unit.test.ts
index 2f5bd1a..be544ca 100644
--- a/gateway/test/unit.test.ts
+++ b/gateway/test/unit.test.ts
@@ -70,6 +70,17 @@ describe("routing/selectSupplier", () => {
     expect(got[0].priceLovelace).toBe(2n);
   });
 
+  it("pins routing to an exact supplier when requested", async () => {
+    const got = await selectCandidates({
+      indexerUrl: "http://ix",
+      model: "m",
+      capabilityId: "llm.text.generate.v1",
+      supplierPkh: "s2",
+      fetchFn: jsonResponse(rows),
+    });
+    expect(got.map((candidate) => candidate.supplierPkh)).toEqual(["s2"]);
+  });
+
   it("routes chat.v1 separately", async () => {
     const got = await selectCandidates({
       indexerUrl: "http://ix",
@@ -118,6 +129,20 @@ describe("openai/validate", () => {
     expect(p.maxTokens).toBe(50);
     expect(p.stream).toBe(false);
   });
+  it("accepts and validates a Vector supplier pin", () => {
+    const supplierPkh = "a".repeat(56);
+    const parsed = parseChatRequest({
+      model: "m",
+      messages: [{ role: "user", content: "hi" }],
+      x_vector: { supplier_pkh: supplierPkh },
+    });
+    expect(parsed.supplierPkh).toBe(supplierPkh);
+    expect(() => parseChatRequest({
+      model: "m",
+      messages: [{ role: "user", content: "hi" }],
+      x_vector: { supplier_pkh: "bad" },
+    })).toThrow(GatewayError);
+  });
   it("rejects tools/functions", () => {
     expect(() => parseChatRequest({ model: "m", messages: [{ role: "user", content: "x" }], tools: [] })).toThrow(GatewayError);
   });
diff --git a/supplier/src/cli/setup-reseller.ts b/supplier/src/cli/setup-reseller.ts
index b23048d..29892c6 100644
--- a/supplier/src/cli/setup-reseller.ts
+++ b/supplier/src/cli/setup-reseller.ts
@@ -298,14 +298,6 @@ async function findOrPostAdvert(
       // Ignore unrelated or malformed script outputs.
     }
   }
-  const otherSeller = sameModel.find(
-    (candidate) => candidate.datum.supplier_pkh !== expected.supplier_pkh,
-  );
-  if (otherSeller) {
-    throw new Error(
-      `marketplace model ${expected.model} is already advertised by another supplier`,
-    );
-  }
   const own = sameModel.filter(
     (candidate) => candidate.datum.supplier_pkh === expected.supplier_pkh,
   );