microsoft/aspire · error · InvalidOperationException

Value for provider has not been set.

Error message

Value for provider has not been set.

What it means

GetValueAsync on a Foundry hosted agent value provider throws InvalidOperationException when Set was never called (_isSet is false). The provider is intentionally write-once/read-after-write, so reading before assignment is a programming error rather than a null return.

Solutions

  1. Ensure Set is called before any GetValueAsync call
  2. Check ordering: wait for the provisioning/configuration phase that assigns provider values before reading
  3. Verify all code paths that create the provider also call Set on it
  4. If unset is legitimate, restructure to use a nullable holder instead of this provider

Example fix

// before
var value = await provider.GetValueAsync(); // throws: never set
// after
if (!isConfigured) provider.Set(defaultValue);
var value = await provider.GetValueAsync();
Defensive patterns

Strategy: try-catch

Validate before calling

// No public IsSet property; wrap reads
async Task<string?> SafeGetAsync(Provider p, CancellationToken ct)
{
    try { return await p.GetValueAsync(ct); }
    catch (InvalidOperationException) { return null; }
}

Try / catch

string? value;
try
{
    value = await provider.GetValueAsync(ct);
}
catch (InvalidOperationException ex) when (ex.Message == "Value for provider has not been set.")
{
    logger.LogError(ex, "Provider read before configuration completed.");
    throw;
}

Prevention

When it happens

Trigger: Calling GetValueAsync before the framework (or your code) has called Set — e.g. reading the value before provisioning/config resolution completes, or a code path that conditionally skips Set.

Common situations: Reading the value too early in the application lifecycle (before the value resolution phase); a conditional branch that fails to call Set; test that reads an unconfigured provider.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/56550820b0380276. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.Foundry/HostedAgent/AzureHostedAgentResource.cs:552

    {
        _isSet = false;
    }

    /// <summary>
    /// Creates a new instance of the <see cref="StaticValueProvider{T}"/> class.
    /// </summary>
    public StaticValueProvider(T value)
    {
        _value = value;
        _isSet = true;
    }

    /// <inheritdoc/>
    public ValueTask<string?> GetValueAsync(CancellationToken cancellationToken = default)
    {
        if (_isSet == false)
        {
            throw new InvalidOperationException("Value for provider has not been set.");
        }
        else
        {
            return ValueTask.FromResult(_value?.ToString());
        }
    }
}

View on GitHub (pinned to 25830f84bd)