microsoft/semantic-kernel · error · KernelException

The step {this.Name} has no functions.

Error message

The step {this.Name} has no functions.

What it means

Thrown by ProcessStepBuilder.ResolveFunctionName (a private method called during target resolution) when FunctionsDict is empty — the step has no kernel functions at all. Resolution requires at least one function to infer or select from.

Source

Thrown at dotnet/src/Experimental/Process.Core/ProcessStepBuilder.cs:133

        if (this.IncomingEdgeGroups.ContainsKey(edgeGroup.GroupId))
        {
            return;
        }

        // Register the group by GroupId.
        this.IncomingEdgeGroups[edgeGroup.GroupId] = edgeGroup;
    }

    /// <summary>
    /// Resolves the function name for the step.
    /// </summary>
    /// <returns></returns>
    /// <exception cref="KernelException"></exception>
    private string ResolveFunctionName()
    {
        if (this.FunctionsDict.Count == 0)
        {
            throw new KernelException($"The step {this.Name} has no functions.");
        }
        else if (this.FunctionsDict.Count > 1)
        {
            throw new KernelException($"The step {this.Name} has more than one function, so a function name must be provided.");
        }

        return this.FunctionsDict.Keys.First();
    }

    /// <summary>
    /// Links the output of the current step to the an input of another step via the specified event type.
    /// </summary>
    /// <param name="eventId">The Id of the event.</param>
    /// <param name="edgeBuilder">The targeted function.</param>
    internal virtual void LinkTo(string eventId, ProcessStepEdgeBuilder edgeBuilder)
    {
        if (!this.Edges.TryGetValue(eventId, out List<ProcessStepEdgeBuilder>? edges) || edges == null)
        {

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Ensure the step class has at least one method decorated with [KernelFunction("name")].
2. Verify the step type is the correct concrete class, not an abstract base or state-only class.
3. Check that kernel function methods are public and properly decorated if using a dynamic loading scenario.

Example fix

// before — step has no kernel functions
public class EmptyStep : KernelProcessStep { }
process.AddStepFromType<EmptyStep>();
// any edge targeting EmptyStep throws

// after — add a kernel function
public class MyStep : KernelProcessStep
{
    [KernelFunction]
    public void DoWork() { }
}
process.AddStepFromType<MyStep>();

if (step.FunctionsDict.Count == 0)
    throw new InvalidOperationException(
        $"Step '{step.Name}' has no kernel functions. Add at least one [KernelFunction] method.");

// proceed with edge targeting

bool HasKernelFunctions(ProcessStepBuilder step) => step.FunctionsDict.Count > 0;

When it happens

Trigger: Targeting a step that has zero [KernelFunction] methods, then attempting to resolve a function name without specifying one (relying on auto-resolution). Also triggered when a step type is loaded but its function metadata is empty.

Common situations: Using a step class with no [KernelFunction]-decorated methods; the step type was loaded dynamically but reflection found no kernel functions (e.g. methods are private or not decorated); using an abstract base class or a state-only step as a process step; version change where functions were removed.

Related errors

• The step {this.Name} has more than one function, so a functi
• The target step {this.Name} has no functions.
• Failed to resolve function target for {step.GetType().Name},
• The target step has more than one function, so a function na
• The function {functionName} does not exist on step {this.Nam

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/897bef46e8ac5fac. Report an issue: GitHub.