WithArgs runs on startup even if WithExplicitStart is called on a service in 13.4.0

[aL3891]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

After upating to 13.4.0, The callback passed to WithArgs() runs on startup even though WithExplicitStart() is specified on the service. In my case this causes a few popup from services to appear, asking for values.
Supplying a value does not actually start the service though and starting the service manually does result in the WithArgs callback being run again.
More specifically, it runs when the dashboard is opened for the first time, so right away when launching with the debugger and when opening the dashboard when just doing aspire run

Expected Behavior

Previously, the WithArgs method did not run at all until the service was started.
after updating, it runs on startup of the dashboard.

Steps To Reproduce

I have a service for adding a migration that looks like this

using Microsoft.Extensions.DependencyInjection;
#pragma warning disable ASPIREINTERACTION001

var builder = DistributedApplication.CreateBuilder(args);
builder.AddExecutable("AddMigration", "dotnet", "", "ef", "migrations", "add")
  .WithExplicitStart()
  .WithArgs(async context =>
  {
      var interactionService = context.ExecutionContext.ServiceProvider.GetRequiredService<IInteractionService>();
      var name = await interactionService.PromptInputAsync("AddMigrations", "Enter Migation Name", new()
      {
          Name = "Migation Name",
          InputType = InputType.Text,
          Required = true,
          Placeholder = "New migration"
      });

      if (name.Canceled)
          throw new OperationCanceledException("Canceled");
      context.Args.Add(name.Data.Value);
  });

builder.Build().Run();

This used to only ask for a migration name if that service was started explicitly from the dashboard

Exceptions (if any)

No response

Aspire doctor output

Aspire Environment Check

Aspire
✅ Aspire CLI version 13.4.0 (channel: stable)

AppHost
✅ AppHost version 13.4.0 (Mma.AppHost\Mma.AppHost.csproj)

.NET SDK
✅ .NET 11.0.100-preview.4.26230.115 installed (x64)

Container Runtime
✅ Podman v5.8.2: running (configured via ASPIRE_CONTAINER_RUNTIME=podman) ← active

Environment
✅ HTTPS development certificate is trusted

Summary: 5 passed, 0 warnings, 0 failed

Aspire CLI Installations

╭──────────────────────────────────────────────┬─────────────────────────────────────────────────┬─────────┬───────────┬─────────────╮
│ Path │ Version │ Channel │ Route │ PATH status │
├──────────────────────────────────────────────┼─────────────────────────────────────────────────┼─────────┼───────────┼─────────────┤
│ C:\Users\aL.aspire\bin\aspire.exe (current) │ 13.4.0+becb48e2d61099e35ae336d527d3875e928d6594 │ stable │ (unknown) │ active │
╰──────────────────────────────────────────────┴─────────────────────────────────────────────────┴─────────┴───────────┴─────────────╯

Anything else?

No response

[joperezr]

🤖 Aspire triage pass — 2026-06-01 23:43 UTC

Area: area-app-model
Kind: regression
Repro: yes-minimal — see code snippet in the issue body (Steps To Reproduce section)
Affected version(s): 13.4.0 (latest stable: 13.4.0; previously worked on 13.3.x per reporter)
Severity: S3 — WithArgs callback fires at dashboard load instead of only on explicit start, surfacing user-input prompts that don't actually start the resource. Core "explicit start" semantics still work if the user dismisses the prompts and starts manually, so a workaround exists but UX is broken.

Urgency: 🟡 vNext — recommend milestone 13.5
Reason: clear 13.4 regression in area-app-model callback ordering with a workaround (S3). 13.4 is snapped and ships Monday; the bar to pull this in is high. Cannot confirm without investigation whether WithArgs callback timing changed specifically in 13.4 vs an earlier 13.x — flagging for human to decide whether to escalate to 13.4.

Suggested owner(s): @JamesNK (score 46), backup @karolz-ms (score 4)
Evidence:

• JamesNK authored 15 of the last ~30 merged PRs labeled area-app-model over the past 90 days (top contributor by a wide margin).
• CODEOWNERS lists @JamesNK @karolz-Aspire for /src/Aspire.Hosting (where WithArgs/WithExplicitStart live).
• karolz-ms merged Fix event order and callback calling during container creation #15503 ("Fix event order and callback calling during container creation") — directly relevant to lifecycle/callback ordering in app-model.

Confidence: medium
Needs human?: yes — regression-window confirmation needed: is this truly 13.4-introduced (warrants 13.4 milestone) or a longer-standing bug surfaced by other changes? Also need a human decision on whether the broken explicit-start + interactive-args scenario clears the 13.4 release-blocking bar.

Dry-run mode — no labels or milestone applied. Reply /triage apply to promote, or edit and reapply.

[mitchdenny]

@danegsta this was the issue that @davidfowl mentioned. I think the usefulness being able to do deferred evaluation of WithArgs(...) until the resource is started is pretty important. Maybe the shape of explicit start + persistent doesn't make sense?

[danegsta]

@danegsta this was the issue that @davidfowl mentioned. I think the usefulness being able to do deferred evaluation of WithArgs(...) until the resource is started is pretty important. Maybe the shape of explicit start + persistent doesn't make sense?

Supporting WithExplicitStart for persistent resources was a community request early in persistent containers and we'd want to keep parity for sure. We also have the problem of there already having been a behavior difference between executable and container resources (executables now match the behavior containers have had for several releases). If anything I'd argue for restoring the same delayed evaluation behavior for executables AND containers, but only when they don't have a persistent lifecycle. That'd restore this behavior and add support for containers while still allowing persistent resources to support WithExplicitStart.