diff --git a/packages/builder/src/vector/poll.ts b/packages/builder/src/vector/poll.ts
index 31d16ee..0db02b9 100644
--- a/packages/builder/src/vector/poll.ts
+++ b/packages/builder/src/vector/poll.ts
@@ -1,4 +1,5 @@
-// Generic bounded polling loop used by vector_await_transaction.
+// Generic bounded polling loop used by vector_await_transaction, plus the
+// logic that picks what each poll attempt actually checks.
 //
 // OgmiosProvider already has an `awaitTx`, but it is not reused here: it
 // hard-codes a 60-attempt budget (~3 minutes at a fixed 3s interval) with no
@@ -44,3 +45,27 @@ export async function pollUntilConfirmed(
   }
   return false;
 }
+
+/**
+ * Choose which confirmation check `pollUntilConfirmed` should run: Koios's
+ * `tx_status` when configured (a direct signal), the outRef heuristic when
+ * it is not - the same preference order as `OgmiosProvider.awaitTx`, without
+ * reusing it (see the file header above).
+ *
+ * Takes both checks as already-built functions, rather than a provider and
+ * txHash, so the selection itself can be pinned with fakes the same way
+ * `pollUntilConfirmed`'s own `now`/`sleep` are injected above - no network
+ * call happens here. Whichever function is selected is returned as-is, not
+ * wrapped in a try/catch, so a rejection from it propagates unchanged
+ * through `pollUntilConfirmed` to the tool's outer `try/catch` - it is not
+ * reinterpreted as "not yet confirmed". `checkKoios` and `checkOutRef`
+ * carrying that same no-swallow contract is the caller's responsibility
+ * (see the vector_await_transaction call site).
+ */
+export function buildConfirmationCheck(
+  koiosConfigured: boolean,
+  checkKoios: () => Promise<boolean>,
+  checkOutRef: () => Promise<boolean>,
+): () => Promise<boolean> {
+  return koiosConfigured ? checkKoios : checkOutRef;
+}
diff --git a/packages/builder/src/vector/vector.ts b/packages/builder/src/vector/vector.ts
index 6f6f508..9cceda7 100644
--- a/packages/builder/src/vector/vector.ts
+++ b/packages/builder/src/vector/vector.ts
@@ -7,14 +7,14 @@ import * as dotenv from 'dotenv';
 import { resolve } from 'path';
 import { fileURLToPath } from 'url';
 import { existsSync } from 'fs';
-import { OgmiosProvider } from '@apexfusion/vector-mcp-shared/provider';
+import { OgmiosProvider, koiosIndicatesConfirmed } from '@apexfusion/vector-mcp-shared/provider';
 import { lovelaceToAda, formatAssetName } from '@apexfusion/vector-mcp-shared/tx';
 import {
   VECTOR_OGMIOS_URL, VECTOR_SUBMIT_URL, VECTOR_KOIOS_URL, VECTOR_EXPLORER_URL, explorerTxLink,
 } from '@apexfusion/vector-mcp-shared/config';
 import { safetyLayer } from './safety.js';
 import { limiterFor } from './rate-limiter.js';
-import { pollUntilConfirmed } from './poll.js';
+import { pollUntilConfirmed, buildConfirmationCheck } from './poll.js';
 import { registerAgentNetworkTools } from './agent-network.js';
 import { registerSelfImprovementTools } from './self-improvement.js';
 import type {
@@ -1151,10 +1151,14 @@ Transaction Hash: ${txHash}
         const budgetMs = (timeoutSeconds ?? 120) * 1000;
         const intervalMs = 3000;
         const confirmed = await pollUntilConfirmed(
-          async () => {
-            const utxos = await provider.getUtxosByOutRef([{ txHash, outputIndex: 0 }]).catch(() => []);
-            return utxos.length > 0;
-          },
+          buildConfirmationCheck(
+            Boolean(VECTOR_KOIOS_URL),
+            async () => koiosIndicatesConfirmed(await provider.getKoiosTxStatus(txHash)),
+            async () => {
+              const utxos = await provider.getUtxosByOutRef([{ txHash, outputIndex: 0 }]);
+              return utxos.length > 0;
+            },
+          ),
           budgetMs,
           intervalMs,
         );
diff --git a/packages/builder/test/poll.test.ts b/packages/builder/test/poll.test.ts
index 46cc936..c5256e2 100644
--- a/packages/builder/test/poll.test.ts
+++ b/packages/builder/test/poll.test.ts
@@ -1,6 +1,6 @@
 import { describe, test } from 'node:test';
 import assert from 'node:assert/strict';
-import { pollUntilConfirmed } from '../src/vector/poll.ts';
+import { pollUntilConfirmed, buildConfirmationCheck } from '../src/vector/poll.ts';
 
 /**
  * A fake clock: `sleep` advances `t` by exactly the requested amount instead
@@ -181,3 +181,113 @@ describe('pollUntilConfirmed', () => {
     assert.ok(Date.now() - start < 1000, 'first attempt succeeds without waiting a full interval');
   });
 });
+
+describe('buildConfirmationCheck', () => {
+  // vector_await_transaction wires this up as:
+  //   buildConfirmationCheck(Boolean(VECTOR_KOIOS_URL), koiosCheck, outRefCheck)
+  // Both checkKoios/checkOutRef stand in for provider calls (Koios tx_status,
+  // Ogmios getUtxosByOutRef) without ever touching the network - this pins
+  // the selection and propagation behavior, not the HTTP calls themselves.
+
+  test('selects checkKoios when Koios is configured, and never calls checkOutRef', async () => {
+    let outRefCalls = 0;
+    const check = buildConfirmationCheck(
+      true,
+      async () => true,
+      async () => { outRefCalls++; return true; },
+    );
+    assert.equal(await check(), true);
+    assert.equal(outRefCalls, 0, 'the outRef check must not run when Koios is preferred');
+  });
+
+  test('selects checkOutRef when Koios is not configured, and never calls checkKoios', async () => {
+    let koiosCalls = 0;
+    const check = buildConfirmationCheck(
+      false,
+      async () => { koiosCalls++; return true; },
+      async () => false,
+    );
+    assert.equal(await check(), false);
+    assert.equal(koiosCalls, 0, 'the Koios check must not run as a fallback is not a retry path');
+  });
+
+  test('propagates the selected check\'s resolved value unchanged, true or false, in either branch', async () => {
+    assert.equal(await buildConfirmationCheck(true, async () => true, async () => { throw new Error('unused'); })(), true);
+    assert.equal(await buildConfirmationCheck(true, async () => false, async () => { throw new Error('unused'); })(), false);
+    assert.equal(await buildConfirmationCheck(false, async () => { throw new Error('unused'); }, async () => true)(), true);
+    assert.equal(await buildConfirmationCheck(false, async () => { throw new Error('unused'); }, async () => false)(), false);
+  });
+
+  test('propagates a rejection from checkKoios rather than treating it as "not yet confirmed"', async () => {
+    const check = buildConfirmationCheck(
+      true,
+      async () => { throw new Error('Koios tx_status query failed (503): upstream down'); },
+      async () => false,
+    );
+    await assert.rejects(check, /Koios tx_status query failed/);
+  });
+
+  test('propagates a rejection from checkOutRef rather than treating it as "not yet confirmed"', async () => {
+    const check = buildConfirmationCheck(
+      false,
+      async () => false,
+      async () => { throw new Error('Ogmios RPC error (500): boom'); },
+    );
+    await assert.rejects(check, /Ogmios RPC error/);
+  });
+
+  describe('composed with pollUntilConfirmed (matching the real vector_await_transaction call site)', () => {
+    function fakeClock(start = 0) {
+      let t = start;
+      const sleeps: number[] = [];
+      return {
+        now: () => t,
+        sleep: async (ms: number) => { sleeps.push(ms); t += ms; },
+        sleeps,
+      };
+    }
+
+    test('a Koios failure on the first attempt rejects immediately, without ever sleeping or falling back to outRef', async () => {
+      const clock = fakeClock();
+      let outRefCalls = 0;
+      const check = buildConfirmationCheck(
+        true,
+        async () => { throw new Error('Koios unreachable'); },
+        async () => { outRefCalls++; return true; },
+      );
+      await assert.rejects(
+        () => pollUntilConfirmed(check, 9000, 3000, clock.now, clock.sleep),
+        /Koios unreachable/,
+      );
+      assert.deepEqual(clock.sleeps, [], 'a check that cannot determine status must not be retried like a pending tx');
+      assert.equal(outRefCalls, 0);
+    });
+
+    test('outRef polling that never confirms resolves false (not an error) once the budget elapses, with Koios not configured', async () => {
+      const clock = fakeClock();
+      let koiosCalls = 0;
+      const check = buildConfirmationCheck(
+        false,
+        async () => { koiosCalls++; return true; },
+        async () => false,
+      );
+      const result = await pollUntilConfirmed(check, 9000, 3000, clock.now, clock.sleep);
+      assert.equal(result, false);
+      assert.equal(koiosCalls, 0);
+    });
+
+    test('Koios reporting confirmed on a later attempt resolves true without exhausting the budget', async () => {
+      const clock = fakeClock();
+      let attempts = 0;
+      const check = buildConfirmationCheck(
+        true,
+        async () => { attempts++; return attempts >= 2; },
+        async () => { throw new Error('outRef must not run when Koios is configured'); },
+      );
+      const result = await pollUntilConfirmed(check, 9000, 3000, clock.now, clock.sleep);
+      assert.equal(result, true);
+      assert.equal(attempts, 2);
+      assert.deepEqual(clock.sleeps, [3000]);
+    });
+  });
+});
diff --git a/packages/shared/src/provider.ts b/packages/shared/src/provider.ts
index 8d787fe..8f48852 100644
--- a/packages/shared/src/provider.ts
+++ b/packages/shared/src/provider.ts
@@ -59,6 +59,25 @@ export function parseSubmitResponse(body: string): string {
   );
 }
 
+/**
+ * Interpret a parsed Koios `tx_status` response body as a confirmation
+ * signal.
+ *
+ * Exported and pure so it can be tested without a network round trip - same
+ * rationale as `parseSubmitResponse` above. By the time this runs, the
+ * caller (`OgmiosProvider.getKoiosTxStatus`) has already thrown on a genuine
+ * transport/HTTP failure, so anything reaching here is a syntactically valid
+ * response from a reachable Koios. A missing hash (empty array - Koios has
+ * not indexed it yet), a present-but-zero-confirmation entry, or a body that
+ * does not match the expected shape are all treated as "not yet confirmed"
+ * (false) rather than an error: none of them mean the check itself failed.
+ */
+export function koiosIndicatesConfirmed(data: unknown): boolean {
+  if (!Array.isArray(data) || data.length === 0) return false;
+  const entry = data[0] as { num_confirmations?: unknown } | undefined;
+  return typeof entry?.num_confirmations === 'number' && entry.num_confirmations > 0;
+}
+
 export class OgmiosProvider implements Provider {
   private ogmiosUrl: string;
   private submitUrl: string;
@@ -286,6 +305,52 @@ export class OgmiosProvider implements Provider {
     throw new Error(`Datum not found for hash: ${datumHash}. Datum lookups require Koios indexer.`);
   }
 
+  /**
+   * Query Koios for a transaction's confirmation status, once.
+   *
+   * Thin and deliberately does not interpret the response - see
+   * `koiosIndicatesConfirmed` above, kept separate so it can be unit tested
+   * without a network round trip. Unlike the Koios branch inside `awaitTx`
+   * below (which swallows every failure into "keep polling"), this throws on
+   * a network failure or a non-OK response: the caller could not determine
+   * status, which is a different situation from "asked, and it is not
+   * confirmed yet", and callers such as `pollUntilConfirmed`
+   * (packages/builder/src/vector/poll.ts) need to be able to tell the two
+   * apart.
+   */
+  async getKoiosTxStatus(txHash: string): Promise<unknown> {
+    if (!this.koiosUrl) {
+      throw new Error(
+        'Koios URL is not configured. Transaction status checks require Koios indexer. ' +
+        'Set VECTOR_KOIOS_URL in your environment.'
+      );
+    }
+
+    const response = await fetch(`${this.koiosUrl}/api/v1/tx_status`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ _tx_hashes: [txHash] }),
+    });
+    if (!response.ok) {
+      const text = await response.text();
+      throw new Error(`Koios tx_status query failed (${response.status}): ${text}`);
+    }
+    return response.json();
+  }
+
+  /**
+   * Required by the @lucid-evolution/lucid `Provider` interface that this
+   * class implements, but otherwise unused repo-wide: `vector_await_transaction`
+   * builds its own poll loop on top of `getKoiosTxStatus`/`getUtxosByOutRef`
+   * (see packages/builder/src/vector/poll.ts) instead of calling this,
+   * because this method's fixed 60-attempt/3s-interval budget cannot be
+   * configured by a caller and it swallows every failure - network error,
+   * non-OK response, malformed body - into "keep polling", which is
+   * indistinguishable from "checked and it is not there yet". Left
+   * unmodified rather than deleted or reworked: TypeScript requires it to
+   * satisfy `implements Provider`, and changing its own retry/error
+   * semantics is out of scope here since nothing depends on them.
+   */
   async awaitTx(txHash: string, checkInterval: number = 3000): Promise<boolean> {
     // Poll for tx confirmation
     const maxAttempts = 60; // ~3 minutes at 3s intervals
diff --git a/packages/shared/test/provider-confirmation.test.ts b/packages/shared/test/provider-confirmation.test.ts
new file mode 100644
index 0000000..f75a624
--- /dev/null
+++ b/packages/shared/test/provider-confirmation.test.ts
@@ -0,0 +1,56 @@
+import { describe, test } from 'node:test';
+import assert from 'node:assert/strict';
+import { koiosIndicatesConfirmed } from '../src/provider.ts';
+
+// koiosIndicatesConfirmed only ever sees a body that Koios already answered
+// with an OK response - getKoiosTxStatus throws before this runs for a
+// network failure or a non-2xx status. So every case here is "reachable and
+// answered", and the only question is whether that answer means confirmed.
+
+describe('koiosIndicatesConfirmed', () => {
+  test('a positive confirmation count means confirmed', () => {
+    assert.equal(koiosIndicatesConfirmed([{ tx_hash: 'a'.repeat(64), num_confirmations: 1 }]), true);
+  });
+
+  test('a larger confirmation count still means confirmed', () => {
+    assert.equal(koiosIndicatesConfirmed([{ tx_hash: 'a'.repeat(64), num_confirmations: 42 }]), true);
+  });
+
+  test('an empty array (Koios has not indexed the hash yet) means not confirmed', () => {
+    assert.equal(koiosIndicatesConfirmed([]), false);
+  });
+
+  test('zero confirmations means not confirmed', () => {
+    assert.equal(koiosIndicatesConfirmed([{ tx_hash: 'a'.repeat(64), num_confirmations: 0 }]), false);
+  });
+
+  test('a missing num_confirmations field means not confirmed, not an error', () => {
+    assert.equal(koiosIndicatesConfirmed([{ tx_hash: 'a'.repeat(64) }]), false);
+  });
+
+  test('a non-array body means not confirmed, not an error', () => {
+    assert.equal(koiosIndicatesConfirmed(null), false);
+    assert.equal(koiosIndicatesConfirmed(undefined), false);
+    assert.equal(koiosIndicatesConfirmed({}), false);
+    assert.equal(koiosIndicatesConfirmed('unexpected'), false);
+  });
+
+  test('a num_confirmations that is not a number means not confirmed, not an error', () => {
+    // Defensive: guards against a future Koios response shape change (e.g. a
+    // stringified count) silently being coerced by a loose truthiness check
+    // instead of being treated as "cannot tell, so say not yet".
+    assert.equal(koiosIndicatesConfirmed([{ num_confirmations: '3' }]), false);
+    assert.equal(koiosIndicatesConfirmed([{ num_confirmations: null }]), false);
+  });
+
+  test('a negative confirmation count means not confirmed', () => {
+    assert.equal(koiosIndicatesConfirmed([{ num_confirmations: -1 }]), false);
+  });
+
+  test('only the first entry is consulted, matching the single-hash query this is always called with', () => {
+    assert.equal(
+      koiosIndicatesConfirmed([{ num_confirmations: 0 }, { num_confirmations: 5 }]),
+      false,
+    );
+  });
+});