diff --git a/src/AppLens.Backend/PlatformLoopService.cs b/src/AppLens.Backend/PlatformLoopService.cs
index e352615..8f7a073 100644
--- a/src/AppLens.Backend/PlatformLoopService.cs
+++ b/src/AppLens.Backend/PlatformLoopService.cs
@@ -114,6 +114,50 @@ await _blackboardStore.AppendAsync(
         return approval;
     }
 
+    public async Task<TuneActionApproval> DecidePendingTuneActionAsync(
+        string proposalId,
+        string approvedBy,
+        bool approved,
+        string rationale,
+        string? correlationId = null,
+        CancellationToken cancellationToken = default)
+    {
+        if (string.IsNullOrWhiteSpace(proposalId))
+        {
+            throw new InvalidOperationException("Tune action proposal id is missing.");
+        }
+
+        var events = await _blackboardStore.ReadAllAsync(cancellationToken).ConfigureAwait(false);
+        var isAlreadyDecided = events.Any(evt =>
+            evt.EventType is BlackboardEventType.ActionApproved or BlackboardEventType.ActionExecuted &&
+            string.Equals(Payload(evt, "proposal_id"), proposalId, StringComparison.OrdinalIgnoreCase));
+
+        if (isAlreadyDecided)
+        {
+            throw new InvalidOperationException($"Tune action proposal {proposalId} was already decided.");
+        }
+
+        var proposedEvent = events
+            .Where(evt => evt.EventType == BlackboardEventType.ActionProposed)
+            .Where(evt => string.Equals(Payload(evt, "proposal_id"), proposalId, StringComparison.OrdinalIgnoreCase))
+            .OrderByDescending(evt => evt.CreatedAt)
+            .FirstOrDefault();
+
+        if (proposedEvent is null)
+        {
+            throw new InvalidOperationException($"Tune action proposal {proposalId} was not found.");
+        }
+
+        return await ApproveTuneActionAsync(
+                ToProposal(proposedEvent),
+                approvedBy,
+                approved,
+                rationale,
+                correlationId ?? proposedEvent.CorrelationId,
+                cancellationToken)
+            .ConfigureAwait(false);
+    }
+
     public async Task<TuneActionRecord> ExecuteTuneActionAsync(
         TunePlanItem item,
         TuneActionProposal proposal,
@@ -170,6 +214,23 @@ private static TuneActionRecord BlockedRecord(TunePlanItem item, string message)
 
     private static string NormalizeCorrelationId(string? correlationId, string prefix) =>
         string.IsNullOrWhiteSpace(correlationId) ? $"{prefix}-{Guid.NewGuid():N}" : correlationId;
+
+    private static TuneActionProposal ToProposal(BlackboardEvent evt) =>
+        new()
+        {
+            ProposalId = Payload(evt, "proposal_id"),
+            PlanItemId = Payload(evt, "plan_item_id"),
+            Kind = Enum.TryParse<ProposedActionKind>(Payload(evt, "kind"), ignoreCase: true, out var kind)
+                ? kind
+                : ProposedActionKind.None,
+            Target = Payload(evt, "target"),
+            TargetContext = Payload(evt, "target_context"),
+            CorrelationId = evt.CorrelationId,
+            ProposedAt = evt.CreatedAt
+        };
+
+    private static string Payload(BlackboardEvent evt, string key) =>
+        evt.Payload.TryGetValue(key, out var value) ? value : "";
 }
 
 file static class TuneActionProposalExtensions
diff --git a/tests/AppLens.Backend.Tests/PlatformLoopServiceTests.cs b/tests/AppLens.Backend.Tests/PlatformLoopServiceTests.cs
index 52e9324..f01a485 100644
--- a/tests/AppLens.Backend.Tests/PlatformLoopServiceTests.cs
+++ b/tests/AppLens.Backend.Tests/PlatformLoopServiceTests.cs
@@ -62,6 +62,62 @@ public async Task Rejected_approval_does_not_call_runtime_and_records_blocked_ex
         Assert.Contains("approval", executionEvent.Payload["message"], StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public async Task Decide_pending_tune_action_by_proposal_id_records_approval_and_closes_dashboard_item()
+    {
+        var runtime = new FakeTuneActionRuntime();
+        var service = CreateService(runtime);
+        var item = StartupItem("startup-docker");
+        var proposal = await service.ProposeTuneActionAsync(item, "corr-decision");
+
+        var approval = await service.DecidePendingTuneActionAsync(
+            proposal.ProposalId,
+            approvedBy: "operator",
+            approved: true,
+            rationale: "Approved from dashboard.",
+            correlationId: "corr-decision");
+
+        var dashboard = await CreateDashboardService().GetPendingActionsAsync();
+        var approvalEvents = await _store.QueryAsync(new BlackboardEventQuery
+        {
+            CorrelationId = "corr-decision",
+            EventType = BlackboardEventType.ActionApproved
+        });
+
+        Assert.Equal(proposal.ProposalId, approval.ProposalId);
+        Assert.True(approval.Approved);
+        Assert.Empty(dashboard);
+        var approvalEvent = Assert.Single(approvalEvents);
+        Assert.Equal("True", approvalEvent.Payload["approved"]);
+        Assert.Equal("operator", approvalEvent.Payload["approved_by"]);
+        Assert.Equal("Approved from dashboard.", approvalEvent.Payload["rationale"]);
+    }
+
+    [Fact]
+    public async Task Decide_pending_tune_action_by_proposal_id_rejects_duplicate_decisions()
+    {
+        var runtime = new FakeTuneActionRuntime();
+        var service = CreateService(runtime);
+        var item = StartupItem("startup-docker");
+        var proposal = await service.ProposeTuneActionAsync(item, "corr-duplicate-decision");
+        await service.DecidePendingTuneActionAsync(
+            proposal.ProposalId,
+            approvedBy: "operator",
+            approved: false,
+            rationale: "Not needed.",
+            correlationId: "corr-duplicate-decision");
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            service.DecidePendingTuneActionAsync(
+                proposal.ProposalId,
+                approvedBy: "operator",
+                approved: true,
+                rationale: "Changed mind.",
+                correlationId: "corr-duplicate-decision"));
+
+        Assert.Contains("already decided", ex.Message, StringComparison.OrdinalIgnoreCase);
+    }
+
     public void Dispose()
     {
         if (Directory.Exists(_root))
@@ -82,6 +138,17 @@ private PlatformLoopService CreateService(FakeTuneActionRuntime runtime) =>
             _store,
             new TuneActionExecutor(runtime));
 
+    private DashboardReadModelService CreateDashboardService() =>
+        new(
+            new ModuleStatusService(new ModuleStatusPaths
+            {
+                AppLensLlmRoot = Path.Combine(_root, "missing-llm"),
+                OracleRoot = Path.Combine(_root, "missing-oracle"),
+                MailboxRoot = Path.Combine(_root, "missing-mailbox"),
+                AppLensZeroRoot = Path.Combine(_root, "missing-zero")
+            }),
+            _store);
+
     private static TunePlanItem StartupItem(string id) =>
         new()
         {