diff --git a/frontend/src/__tests__/plans.test.ts b/frontend/src/__tests__/plans.test.ts
index 333805fbe..afe3ebda3 100644
--- a/frontend/src/__tests__/plans.test.ts
+++ b/frontend/src/__tests__/plans.test.ts
@@ -19,7 +19,8 @@ jest.mock('../api', () => ({
   createPlannedPurchases: jest.fn(),
   listPlanAccounts: jest.fn().mockResolvedValue([]),
   setPlanAccounts: jest.fn().mockResolvedValue(undefined),
-  listAccounts: jest.fn().mockResolvedValue([])
+  listAccounts: jest.fn().mockResolvedValue([]),
+  getAccount: jest.fn().mockResolvedValue(null)
 }));
 
 // Mock state module
@@ -1264,6 +1265,139 @@ describe('Plans Module', () => {
 
       expect((document.getElementById('plan-id') as HTMLInputElement).value).toBe('');
     });
+
+    // #770: Purchase Configuration section should be prefilled from the
+    // selected commitment when exactly one commitment is passed in the snapshot.
+    describe('prefill from single selected commitment (#770)', () => {
+      const fixture: api.Recommendation = {
+        id: 'rec-770',
+        provider: 'aws',
+        service: 'ec2',
+        region: 'us-east-1',
+        resource_type: 't3.medium',
+        count: 1,
+        term: 1,
+        payment: 'partial-upfront',
+        upfront_cost: 100,
+        monthly_cost: 20,
+        savings: 15,
+        selected: true,
+        purchased: false,
+        cloud_account_id: 'acct-uuid-123',
+      };
+
+      test('prefills provider and service selects', () => {
+        openCreatePlanModal([fixture]);
+
+        expect((document.getElementById('plan-provider') as HTMLSelectElement).value).toBe('aws');
+        expect((document.getElementById('plan-service') as HTMLSelectElement).value).toBe('ec2');
+      });
+
+      test('prefills term and payment selects', () => {
+        openCreatePlanModal([fixture]);
+
+        expect((document.getElementById('plan-term') as HTMLSelectElement).value).toBe('1');
+        expect((document.getElementById('plan-payment') as HTMLSelectElement).value).toBe('partial-upfront');
+      });
+
+      test('calls populateTermSelect and populatePaymentSelect with provider+service', () => {
+        openCreatePlanModal([fixture]);
+
+        expect(populateTermSelect).toHaveBeenCalledWith(
+          expect.any(HTMLSelectElement), 'aws', 'ec2'
+        );
+        expect(populatePaymentSelect).toHaveBeenCalledWith(
+          expect.any(HTMLSelectElement), 'aws', 'ec2'
+        );
+      });
+
+      test('fetches account by cloud_account_id to prefill chip', async () => {
+        (api.getAccount as jest.Mock).mockResolvedValueOnce({
+          id: 'acct-uuid-123',
+          name: 'Prod AWS',
+          external_id: '123456789012',
+        });
+
+        openCreatePlanModal([fixture]);
+
+        // Wait for the async prefillAccountChipFromId to settle
+        await Promise.resolve();
+        await Promise.resolve();
+
+        expect(api.getAccount).toHaveBeenCalledWith('acct-uuid-123');
+        const chips = document.getElementById('plan-accounts-selected');
+        expect(chips?.textContent).toContain('Prod AWS');
+        const hiddenIds = (document.getElementById('plan-account-ids') as HTMLInputElement).value;
+        expect(hiddenIds).toContain('acct-uuid-123');
+      });
+
+      test('does not throw and leaves account section empty when getAccount fails', async () => {
+        (api.getAccount as jest.Mock).mockRejectedValueOnce(new Error('network error'));
+
+        openCreatePlanModal([fixture]);
+
+        await Promise.resolve();
+        await Promise.resolve();
+
+        // Account section should be empty -- no chip added
+        const hiddenIds = (document.getElementById('plan-account-ids') as HTMLInputElement).value;
+        expect(hiddenIds).toBe('');
+      });
+
+      test('skips prefill when no cloud_account_id present', async () => {
+        const noAccount: api.Recommendation = { ...fixture, cloud_account_id: undefined };
+        openCreatePlanModal([noAccount]);
+
+        await Promise.resolve();
+
+        expect(api.getAccount).not.toHaveBeenCalled();
+      });
+
+      test('discards stale getAccount result when modal is reopened before promise resolves', async () => {
+        // Simulate a slow first getAccount call that resolves after the modal
+        // is closed and a new modal session starts (the race condition fixed
+        // by the planModalSession guard — #770 CR Major).
+        let resolveFirstCall!: (value: api.CloudAccount) => void;
+        const firstCallPromise = new Promise<api.CloudAccount>(resolve => {
+          resolveFirstCall = resolve;
+        });
+
+        (api.getAccount as jest.Mock)
+          .mockReturnValueOnce(firstCallPromise) // first open: hangs
+          .mockResolvedValueOnce(null);          // second open: no account
+
+        // First modal open with cloud_account_id
+        openCreatePlanModal([fixture]);
+
+        // Close and reopen — this increments planModalSession
+        closePlanModal();
+        const noAccount: api.Recommendation = { ...fixture, cloud_account_id: undefined };
+        openCreatePlanModal([noAccount]);
+
+        // Now resolve the stale first promise — should be discarded
+        resolveFirstCall({ id: 'acct-uuid-123', name: 'Prod AWS', external_id: '123456789012' } as api.CloudAccount);
+        await Promise.resolve();
+        await Promise.resolve();
+
+        // The stale chip must NOT have been added to the new modal session
+        const hiddenIds = (document.getElementById('plan-account-ids') as HTMLInputElement).value;
+        expect(hiddenIds).toBe('');
+        const chips = document.getElementById('plan-accounts-selected');
+        expect(chips?.textContent).not.toContain('Prod AWS');
+      });
+
+      test('does not prefill when snapshot has more than one commitment', () => {
+        const second: api.Recommendation = { ...fixture, id: 'rec-771', service: 'rds' };
+        openCreatePlanModal([fixture, second]);
+
+        // populateTermSelect is called by setupRampScheduleHandlers / updateCommitmentOptions
+        // but NOT by prefillPurchaseConfigFromCommitment (which only runs for length===1)
+        // The provider/service select should NOT be forced to either rec's values
+        // We assert that the service select was not forced to 'ec2' alone
+        // (a multi-commitment plan requires manual selection)
+        expect(api.getAccount).not.toHaveBeenCalled();
+      });
+    });
   });
 
   describe('openNewPlanModal', () => {
diff --git a/frontend/src/plans.ts b/frontend/src/plans.ts
index 39a9cb395..fc232d5ca 100644
--- a/frontend/src/plans.ts
+++ b/frontend/src/plans.ts
@@ -701,6 +701,12 @@ export function closePlanModal(): void {
 // Selected accounts for the plan modal
 let planSelectedAccounts: Array<{ id: string; name: string; external_id: string }> = [];
 
+// Monotonically incrementing counter scoped to the plan modal lifecycle.
+// Incremented each time the create modal opens so that async callbacks
+// from a previous session (stale promises) can detect they're out-of-date
+// and discard their results rather than mutating state in the new session.
+let planModalSession = 0;
+
 /**
  * Render selected account chips in the plan modal
  */
@@ -822,6 +828,68 @@ async function setupPlanAccountsSection(planId?: string): Promise<void> {
   }
 }
 
+/**
+ * Prefill the Purchase Configuration section (provider / service / term /
+ * payment) from a single selected commitment. Called after form.reset() so
+ * the defaults are already in place; each field is still editable. (#770)
+ */
+function prefillPurchaseConfigFromCommitment(rec: api.Recommendation): void {
+  const providerSelect = document.getElementById('plan-provider') as HTMLSelectElement | null;
+  const serviceSelect = document.getElementById('plan-service') as HTMLSelectElement | null;
+  const termSelect = document.getElementById('plan-term') as HTMLSelectElement | null;
+  const paymentSelect = document.getElementById('plan-payment') as HTMLSelectElement | null;
+
+  if (!providerSelect || !serviceSelect || !termSelect || !paymentSelect) return;
+
+  const provider = rec.provider ?? '';
+  const service = rec.service ?? '';
+
+  if (provider) providerSelect.value = provider;
+  if (service) serviceSelect.value = service;
+
+  // Repopulate term/payment options for the chosen provider+service, then
+  // apply the commitment's own values so the dropdowns are consistent.
+  if (provider && service) {
+    populateTermSelect(termSelect, provider, service);
+    populatePaymentSelect(paymentSelect, provider, service);
+  }
+
+  if (rec.term != null) termSelect.value = String(rec.term);
+  const normalizedPayment = rec.payment ? normalizePaymentValue(rec.payment, provider) : '';
+  if (normalizedPayment) paymentSelect.value = normalizedPayment;
+}
+
+/**
+ * Fetch the account with the given internal UUID and add it as a pre-selected
+ * chip in the plan modal accounts section. Runs after setupPlanAccountsSection
+ * has reset the chip list for the create flow. Silently no-ops on failure so
+ * the user can still pick the account manually. (#770)
+ *
+ * @param accountId - Internal UUID of the account to prefill.
+ * @param session   - planModalSession value captured at call time. If the
+ *                    modal is closed and reopened before this promise resolves,
+ *                    the counter will have advanced and the stale result is
+ *                    discarded to prevent wrong-modal pollution. (#770 CR)
+ */
+async function prefillAccountChipFromId(accountId: string, session: number): Promise<void> {
+  try {
+    const account = await api.getAccount(accountId);
+    // Session guard: discard the result if the modal was closed and reopened
+    // while this promise was in-flight. planModalSession is incremented on
+    // each new modal open, so a mismatch means this callback is stale.
+    if (session !== planModalSession) return;
+    // Guard: only add if the chip is not already present (e.g. a concurrent
+    // edit flow somehow set it) and the account record is usable.
+    if (account && account.id && !planSelectedAccounts.some(a => a.id === account.id)) {
+      planSelectedAccounts.push({ id: account.id, name: account.name, external_id: account.external_id });
+      renderPlanAccountChips();
+      updatePlanAccountIdsField();
+    }
+  } catch {
+    // Non-critical: the user can still search and add the account manually.
+  }
+}
+
 /**
  * Open create plan modal with selected recommendations.
  *
@@ -847,6 +915,13 @@ export function openCreatePlanModal(snapshot?: readonly api.Recommendation[]): v
   (document.getElementById('plan-id') as HTMLInputElement).value = '';
   (document.getElementById('plan-form') as HTMLFormElement | null)?.reset();
 
+  // When exactly one commitment is selected, prefill the Purchase
+  // Configuration fields so the user does not have to re-enter them.
+  // Fields are still fully editable after prefill. (#770)
+  if (pendingPlanRecommendations.length === 1) {
+    prefillPurchaseConfigFromCommitment(pendingPlanRecommendations[0]!);
+  }
+
   // Set up ramp schedule change handlers for dynamic plan name
   setupRampScheduleHandlers();
 
@@ -856,7 +931,21 @@ export function openCreatePlanModal(snapshot?: readonly api.Recommendation[]): v
   // Generate initial plan name
   updatePlanNameFromSchedule();
 
+  // Stamp a new session so any in-flight prefillAccountChipFromId promise
+  // from a prior modal open can detect it belongs to a stale session and
+  // discard its result without mutating planSelectedAccounts. (#770 CR)
+  planModalSession += 1;
+
+  // setupPlanAccountsSection clears planSelectedAccounts and re-renders.
+  // When a single commitment carries a cloud_account_id, we look up that
+  // account after the section has reset and add it as a pre-selected chip.
   void setupPlanAccountsSection();
+  if (pendingPlanRecommendations.length === 1) {
+    const accountId = pendingPlanRecommendations[0]!.cloud_account_id;
+    if (accountId) {
+      void prefillAccountChipFromId(accountId, planModalSession);
+    }
+  }
 
   const planModal = document.getElementById('plan-modal');
   if (planModal) {