diff --git a/README.md b/README.md
index b3c6042..d2301d2 100644
--- a/README.md
+++ b/README.md
@@ -52,10 +52,12 @@ The SpdxTool can be driven using workflow yaml files of the following format:
 ```yaml
 steps:
 - command: <command-name>
-  <arguments mapping>
+  inputs:
+    <arguments mapping>
 
 - command: <command-name>
-  <arguments mapping>
+  inputs:
+    <arguments mapping>
 ```
 
 ## YAML Commands
@@ -67,24 +69,30 @@ steps:
 
   # Run a separate workflow file
 - command: run-workflow
-  file: other-workflow-file.yaml
+  inputs:
+    file: other-workflow-file.yaml
+    parameters:
+      <optional parameters>
 
   # Create a summary markdown from the specified SPDX document
 - command: to-markdown
-  spdx: input.spdx.json
-  markdown: output.md
+  inputs:
+    spdx: input.spdx.json
+    markdown: output.md
 
   # Rename the SPDX-ID of an element in an SPDX document
 - command: rename-id
-  spdx: <spdx.json>
-  old: <old-id>
-  new: <new-id>
+  inputs:
+    spdx: <spdx.json>
+    old: <old-id>
+    new: <new-id>
 
   # Copy a package from one SPDX document to another SPDX document  
 - command: copy-package
-  from: <from.spdx.json>
-  to: <to.spdx.json>
-  package: <package>
-  relationship: <relationship>
-  element: <element>
+  inputs:
+    from: <from.spdx.json>
+    to: <to.spdx.json>
+    package: <package>
+    relationship: <relationship>
+    element: <element>
 ```
diff --git a/src/DemaConsulting.SpdxTool/Commands/Command.cs b/src/DemaConsulting.SpdxTool/Commands/Command.cs
index 6f28e39..23322c4 100644
--- a/src/DemaConsulting.SpdxTool/Commands/Command.cs
+++ b/src/DemaConsulting.SpdxTool/Commands/Command.cs
@@ -17,5 +17,88 @@ public abstract class Command
     /// Run the command
     /// </summary>
     /// <param name="step">Command step</param>
-    public abstract void Run(YamlMappingNode step);
-}
\ No newline at end of file
+    /// <param name="variables">Workflow variables</param>
+    public abstract void Run(YamlMappingNode step, Dictionary<string, string> variables);
+
+    /// <summary>
+    /// Expand variables in text
+    /// </summary>
+    /// <param name="text">Text to expand</param>
+    /// <param name="variables">Variables</param>
+    /// <returns>Expanded text</returns>
+    /// <exception cref="InvalidOperationException">on error</exception>
+    public static string Expand(string text, Dictionary<string, string> variables)
+    {
+        while (true)
+        {
+            // Find the last macro to expand
+            var start = text.LastIndexOf("${{", StringComparison.Ordinal);
+            if (start < 0)
+                return text;
+
+            // Find the end of the macro
+            var end = text.IndexOf("}}", start, StringComparison.Ordinal);
+            if (end < 0)
+                throw new InvalidOperationException("Unmatched '${{' in variable expansion");
+
+            // Get the variable name
+            var name = text[(start + 3)..end].Trim();
+
+            // Replace the variable
+            if (!variables.TryGetValue(name, out var value))
+                throw new InvalidOperationException($"Undefined variable {name}");
+
+            // Apply the replacement
+            text = text[..start] + value + text[(end + 2)..];
+        }
+    }
+
+    /// <summary>
+    /// Get a map from a map
+    /// </summary>
+    /// <param name="map">Parent map node</param>
+    /// <param name="name">Entry name</param>
+    /// <returns>Child map node or null</returns>
+    public static YamlMappingNode? GetMapMap(YamlMappingNode? map, string name)
+    {
+        // Handle null map
+        if (map == null)
+            return null;
+
+        // Get the entry
+        return map.Children.TryGetValue(name, out var value) ? value as YamlMappingNode : null;
+    }
+
+    /// <summary>
+    /// Get a sequence from a map
+    /// </summary>
+    /// <param name="map">Parent map node</param>
+    /// <param name="name">Entry name</param>
+    /// <returns>Child sequence node or null</returns>
+    public static YamlSequenceNode? GetMapSequence(YamlMappingNode? map, string name)
+    {
+        // Handle null map
+        if (map == null)
+            return null;
+
+        // Get the entry
+        return map.Children.TryGetValue(name, out var value) ? value as YamlSequenceNode : null;
+    }
+
+    /// <summary>
+    /// Get a map value from a map
+    /// </summary>
+    /// <param name="map">Map node</param>
+    /// <param name="key">Map key</param>
+    /// <param name="variables">Variables for expansion</param>
+    /// <returns>Map value or null</returns>
+    public static string? GetMapString(YamlMappingNode? map, string key, Dictionary<string, string> variables)
+    {
+        // Handle null map
+        if (map == null)
+            return null;
+
+        // Get the parameter
+        return map.Children.TryGetValue(key, out var value) ? Expand(value.ToString(), variables) : null;
+    }
+}
diff --git a/src/DemaConsulting.SpdxTool/Commands/CopyPackageCommand.cs b/src/DemaConsulting.SpdxTool/Commands/CopyPackageCommand.cs
index e3adfec..7417d1a 100644
--- a/src/DemaConsulting.SpdxTool/Commands/CopyPackageCommand.cs
+++ b/src/DemaConsulting.SpdxTool/Commands/CopyPackageCommand.cs
@@ -31,11 +31,12 @@ public class CopyPackageCommand : Command
             "",
             "From a YAML file this can be used as:",
             "  - command: copy-package",
-            "    from: <from.spdx.json>",
-            "    to: <to.spdx.json>",
-            "    package: <package>",
-            "    relationship: <relationship>",
-            "    element: <element>",
+            "    inputs:",
+            "      from: <from.spdx.json>",
+            "      to: <to.spdx.json>",
+            "      package: <package>",
+            "      relationship: <relationship>",
+            "      element: <element>",
             "",
             "The <package> argument is the name of a package in <from.spdx.json> to copy.",
             "The <relationship> argument describes the <element> relationship to <package>.",
@@ -65,31 +66,33 @@ public override void Run(string[] args)
     }
 
     /// <inheritdoc />
-    public override void Run(YamlMappingNode step)
+    public override void Run(YamlMappingNode step, Dictionary<string, string> variables)
     {
-        // Get the from-filename
-        if (!step.Children.TryGetValue("from", out var fromFile))
-            throw new YamlException(step.Start, step.End, "'copy-package' command missing 'from' parameter");
+        // Get the step inputs
+        var inputs = GetMapMap(step, "inputs");
 
-        // Get the to-filename
-        if (!step.Children.TryGetValue("to", out var toFile))
-            throw new YamlException(step.Start, step.End, "'copy-package' command missing 'to' parameter");
+        // Get the 'from' input
+        var fromFile = GetMapString(inputs, "from", variables) ??
+                       throw new YamlException(step.Start, step.End, "'copy-package' missing 'from' input");
 
-        // Get the package name
-        if (!step.Children.TryGetValue("package", out var package))
-            throw new YamlException(step.Start, step.End, "'copy-package' command missing 'package' parameter");
+        // Get the 'to' input
+        var toFile = GetMapString(inputs, "to", variables) ??
+                     throw new YamlException(step.Start, step.End, "'copy-package' missing 'to' input");
 
-        // Get the relationship type
-        if (!step.Children.TryGetValue("relationship", out var relationship))
-            throw new YamlException(step.Start, step.End, "'copy-package' command missing 'relationship' parameter");
+        // Get the 'package' input
+        var package = GetMapString(inputs, "package", variables) ??
+                      throw new YamlException(step.Start, step.End, "'copy-package' missing 'package' input");
 
-        // Get the element name
-        if (!step.Children.TryGetValue("element", out var element))
-            throw new YamlException(step.Start, step.End, "'copy-package' command missing 'element' parameter");
+        // Get the 'relationship' input
+        var relationship = GetMapString(inputs, "relationship", variables) ??
+                           throw new YamlException(step.Start, step.End, "'copy-package' missing 'relationship' input");
+
+        // Get the 'element' input
+        var element = GetMapString(inputs, "element", variables) ??
+                      throw new YamlException(step.Start, step.End, "'copy-package' missing 'element' input");
 
         // Copy the package
-        CopyPackage(fromFile.ToString(), toFile.ToString(), package.ToString(), relationship.ToString(),
-            element.ToString());
+        CopyPackage(fromFile, toFile, package, relationship, element);
     }
 
     /// <summary>
diff --git a/src/DemaConsulting.SpdxTool/Commands/HelpCommand.cs b/src/DemaConsulting.SpdxTool/Commands/HelpCommand.cs
index 7ee43d4..d6bc329 100644
--- a/src/DemaConsulting.SpdxTool/Commands/HelpCommand.cs
+++ b/src/DemaConsulting.SpdxTool/Commands/HelpCommand.cs
@@ -29,7 +29,8 @@ public class HelpCommand : Command
             "",
             "From a YAML file this can be used as:",
             "  - command: help",
-            "    about: <command>"
+            "    inputs:",
+            "      about: <command>"
         },
         Instance);
 
@@ -52,14 +53,17 @@ public override void Run(string[] args)
     }
 
     /// <inheritdoc />
-    public override void Run(YamlMappingNode step)
+    public override void Run(YamlMappingNode step, Dictionary<string, string> variables)
     {
-        // Get the about command
-        if (!step.Children.TryGetValue("about", out var about))
-            throw new YamlException(step.Start, step.End, "'help' command missing 'about' parameter");
+        // Get the step inputs
+        var inputs = GetMapMap(step, "inputs");
+
+        // Get the 'about' input
+        var about = GetMapString(inputs, "about", variables) ??
+                    throw new YamlException(step.Start, step.End, "'help' command missing 'about' input");
 
         // Generate the markdown
-        ShowUsage(about.ToString());
+        ShowUsage(about);
     }
 
     /// <summary>
diff --git a/src/DemaConsulting.SpdxTool/Commands/RenameIdCommand.cs b/src/DemaConsulting.SpdxTool/Commands/RenameIdCommand.cs
index 7437f2c..0a46e7e 100644
--- a/src/DemaConsulting.SpdxTool/Commands/RenameIdCommand.cs
+++ b/src/DemaConsulting.SpdxTool/Commands/RenameIdCommand.cs
@@ -30,9 +30,10 @@ public class RenameIdCommand : Command
             "",
             "From a YAML file this can be used as:",
             "  - command: rename-id",
-            "    spdx: <spdx.json>",
-            "    old: <old-id>",
-            "    new: <new-id>"
+            "    inputs:",
+            "      spdx: <spdx.json>",
+            "      old: <old-id>",
+            "      new: <new-id>"
         },
         Instance);
 
@@ -55,22 +56,25 @@ public override void Run(string[] args)
     }
 
     /// <inheritdoc />
-    public override void Run(YamlMappingNode step)
+    public override void Run(YamlMappingNode step, Dictionary<string, string> variables)
     {
-        // Get the spdx filename
-        if (!step.Children.TryGetValue("spdx", out var spdxFile))
-            throw new YamlException(step.Start, step.End, "'rename-id' command missing 'spdx' parameter");
+        // Get the step inputs
+        var inputs = GetMapMap(step, "inputs");
 
-        // Get the old ID
-        if (!step.Children.TryGetValue("old", out var oldId))
-            throw new YamlException(step.Start, step.End, "'rename-id' command missing 'old' parameter");
+        // Get the 'spdx' input
+        var spdxFile = GetMapString(inputs, "spdx", variables) ??
+                       throw new YamlException(step.Start, step.End, "'rename-id' command missing 'spdx' input");
 
-        // Get the new ID
-        if (!step.Children.TryGetValue("new", out var newId))
-            throw new YamlException(step.Start, step.End, "'rename-id' command missing 'new' parameter");
+        // Get the 'new' input
+        var newId = GetMapString(inputs, "new", variables) ??
+                    throw new YamlException(step.Start, step.End, "'rename-id' command missing 'new' input");
+
+        // Get the 'old' input
+        var oldId = GetMapString(inputs, "old", variables) ?? 
+                    throw new YamlException(step.Start, step.End, "'rename-id' command missing 'spdx' input");
 
         // Rename the ID
-        RenameId(spdxFile.ToString(), oldId.ToString(), newId.ToString());
+        RenameId(spdxFile, oldId, newId);
     }
 
     /// <summary>
diff --git a/src/DemaConsulting.SpdxTool/Commands/RunWorkflowCommand.cs b/src/DemaConsulting.SpdxTool/Commands/RunWorkflowCommand.cs
index 82774b1..cc06e13 100644
--- a/src/DemaConsulting.SpdxTool/Commands/RunWorkflowCommand.cs
+++ b/src/DemaConsulting.SpdxTool/Commands/RunWorkflowCommand.cs
@@ -25,11 +25,15 @@ public class RunWorkflowCommand : Command
             "This command runs the steps specified in the workflow.yaml file.",
             "",
             "From the command-line this can be used as:",
-            "  spdx-tool run-workflow <workflow.yaml>",
+            "  spdx-tool run-workflow <workflow.yaml> [parameter=value] [parameter=value]...",
             "",
             "From a YAML file this can be used as:",
             "  - command: run-workflow",
-            "    file: <workflow.yaml>"
+            "    inputs:",
+            "      file: <workflow.yaml>",
+            "      parameters:",
+            "        name: value",
+            "        name: value"
         },
         Instance);
 
@@ -43,32 +47,64 @@ private RunWorkflowCommand()
     /// <inheritdoc />
     public override void Run(string[] args)
     {
-        // Report an error if the number of arguments is not 1
-        if (args.Length != 1)
+        // Report an error if the number of arguments is less than 1
+        if (args.Length < 1)
             throw new CommandUsageException("'run-workflow' command missing arguments");
 
+        // Parse the parameters
+        var parameters = new Dictionary<string, string>();
+        foreach (var arg in args.Skip(1))
+        {
+            // Verify the parameter is in the form key=value
+            var sep = arg.IndexOf('=');
+            if (sep < 0)
+                throw new CommandUsageException($"Invalid argument: {arg}");
+
+            // Add the parameter
+            var key = arg[..sep];
+            var value = arg[(sep + 1)..];
+            parameters[key] = value;
+        }
+
         // Execute the workflow
-        Execute(args[0]);
+        Execute(args[0], parameters);
     }
 
     /// <inheritdoc />
-    public override void Run(YamlMappingNode step)
+    public override void Run(YamlMappingNode step, Dictionary<string, string> variables)
     {
-        // Get the workflow filename
-        if (!step.Children.TryGetValue("file", out var file))
-            throw new YamlException(step.Start, step.End, "'run-workflow' command missing 'file' parameter");
+        // Get the step inputs
+        var inputs = GetMapMap(step, "input");
+
+        // Get the 'file' input
+        var file = GetMapString(inputs, "file", variables) ?? 
+                   throw new YamlException(step.Start, step.End, "'run-workflow' command missing 'file' input");
+
+        // Get the parameters
+        var parameters = new Dictionary<string, string>();
+        if (GetMapMap(inputs, "parameters") is { } parametersMap)
+        {
+            // Process all the parameters
+            foreach (var (keyNode, valueNode) in parametersMap.Children)
+            {
+                var key = keyNode.ToString();
+                var value = valueNode.ToString();
+                parameters[key] = Expand(value, variables);
+            }
+        }
 
         // Execute the workflow
-        Execute(file.ToString());
+        Execute(file, parameters);
     }
 
     /// <summary>
     /// Execute the workflow
     /// </summary>
     /// <param name="workflowFile">Workflow file</param>
+    /// <param name="parameters">Workflow parameters</param>
     /// <exception cref="CommandUsageException">On usage error</exception>
     /// <exception cref="YamlException">On workflow error</exception>
-    public static void Execute(string workflowFile)
+    public static void Execute(string workflowFile, Dictionary<string, string> parameters)
     {
         // Verify the file exists
         if (!File.Exists(workflowFile))
@@ -85,10 +121,35 @@ public static void Execute(string workflowFile)
                        throw new CommandErrorException(
                            $"Workflow {workflowFile} missing root mapping node");
 
+            // Process the parameters definitions into local variables
+            var variables = new Dictionary<string, string>();
+            if (GetMapMap(root, "parameters") is { } parametersMap)
+            {
+                // Process all the parameters
+                foreach (var (keyNode, valueNode) in parametersMap.Children)
+                {
+                    var key = keyNode.ToString();
+                    var value = Expand(valueNode.ToString(), variables);
+                    variables[key] = Expand(value, parameters);
+                }
+            }
+
+            // Apply the provided parameters to our variables
+            foreach (var (key, value) in parameters)
+            {
+                if (!variables.ContainsKey(key))
+                    throw new CommandErrorException(
+                        $"Workflow {workflowFile} parameter {key} not defined");
+
+                variables[key] = Expand(value, variables);
+            }
+
             // Get the steps
-            var steps = root["steps"] as YamlSequenceNode ??
+            var steps = GetMapSequence(root, "steps") ??
                         throw new CommandErrorException(
                             $"Workflow {workflowFile} missing steps");
+
+            // Execute the steps
             foreach (var stepNode in steps)
             {
                 // Get the step
@@ -108,7 +169,7 @@ public static void Execute(string workflowFile)
                         $"Unknown command: '{command}'");
 
                 // Run the command
-                entry.Instance.Run(step);
+                entry.Instance.Run(step, variables);
             }
         }
         catch (KeyNotFoundException ex)
diff --git a/src/DemaConsulting.SpdxTool/Commands/ToMarkdownCommand.cs b/src/DemaConsulting.SpdxTool/Commands/ToMarkdownCommand.cs
index db27073..fadeda7 100644
--- a/src/DemaConsulting.SpdxTool/Commands/ToMarkdownCommand.cs
+++ b/src/DemaConsulting.SpdxTool/Commands/ToMarkdownCommand.cs
@@ -31,8 +31,9 @@ public class ToMarkdownCommand : Command
             "",
             "From a YAML file this can be used as:",
             "  - command: to-markdown",
-            "    spdx: <spdx.yaml>",
-            "    markdown: <out.md>"
+            "    inputs:",
+            "      spdx: <spdx.yaml>",
+            "      markdown: <out.md>"
         },
         Instance);
 
@@ -55,18 +56,21 @@ public override void Run(string[] args)
     }
 
     /// <inheritdoc />
-    public override void Run(YamlMappingNode step)
+    public override void Run(YamlMappingNode step, Dictionary<string, string> variables)
     {
-        // Get the SPDX filename
-        if (!step.Children.TryGetValue("spdx", out var spdxFile))
-            throw new YamlException(step.Start, step.End, "'to-markdown' command missing 'spdx' parameter");
+        // Get the step inputs
+        var inputs = GetMapMap(step, "inputs");
 
-        // Get the Markdown filename
-        if (!step.Children.TryGetValue("markdown", out var markdownFile))
-            throw new YamlException(step.Start, step.End, "'to-markdown' command missing 'markdown' parameter");
+        // Get the 'spdx' input
+        var spdxFile = GetMapString(inputs, "spdx", variables) ?? 
+                       throw new YamlException(step.Start, step.End, "'to-markdown' command missing 'spdx' input");
+
+        // Get the 'markdown' input
+        var markdownFile = GetMapString(inputs, "markdown", variables) ??
+                           throw new YamlException(step.Start, step.End, "'to-markdown' command missing 'spdx' input");
 
         // Generate the markdown
-        Generate(spdxFile.ToString(), markdownFile.ToString());
+        Generate(spdxFile, markdownFile);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestCommand.cs b/test/DemaConsulting.SpdxTool.Tests/TestCommand.cs
new file mode 100644
index 0000000..10aab25
--- /dev/null
+++ b/test/DemaConsulting.SpdxTool.Tests/TestCommand.cs
@@ -0,0 +1,75 @@
+using DemaConsulting.SpdxTool.Commands;
+using YamlDotNet.RepresentationModel;
+
+namespace DemaConsulting.SpdxTool.Tests;
+
+[TestClass]
+public class TestCommand
+{
+    [TestMethod]
+    public void CommandExpandMissing()
+    {
+        // Test expanding a missing variable
+        const string text = "Hello, ${{ name }}!";
+        var variables = new Dictionary<string, string>();
+        Assert.ThrowsException<InvalidOperationException>(() => Command.Expand(text, variables));
+    }
+
+    [TestMethod]
+    public void CommandExpandNothing()
+    {
+        // Test expanding nothing
+        const string text = "Hello, world!";
+        var variables = new Dictionary<string, string>();
+        var result = Command.Expand(text, variables);
+        Assert.AreEqual(text, result);
+    }
+
+    [TestMethod]
+    public void CommandExpandBasic()
+    {
+        // Test expanding a basic variable
+        const string text = "Hello, ${{ name }}!";
+        var variables = new Dictionary<string, string> { { "name", "world" } };
+        var result = Command.Expand(text, variables);
+        Assert.AreEqual("Hello, world!", result);
+    }
+
+    [TestMethod]
+    public void CommandExpandDouble()
+    {
+        // Test expanding a nested variable
+        const string text = "Hello, ${{ name }}!";
+        var variables = new Dictionary<string, string> { { "name", "${{ target }}" }, { "target", "world" } };
+        var result = Command.Expand(text, variables);
+        Assert.AreEqual("Hello, world!", result);
+    }
+
+    [TestMethod]
+    public void CommandExpandNested()
+    {
+        // Test expanding a nested variable
+        const string text = "Hello, ${{ variable_${{ test }} }}!";
+        var variables = new Dictionary<string, string> { { "variable_foo", "world" }, { "test", "foo" } };
+        var result = Command.Expand(text, variables);
+        Assert.AreEqual("Hello, world!", result);
+    }
+
+    [TestMethod]
+    public void CommandGetMapStringMissing()
+    {
+        // Test getting a missing parameter
+        var map = new YamlMappingNode();
+        var variables = new Dictionary<string, string>();
+        Assert.IsNull(Command.GetMapString(map, "parameter", variables));
+    }
+
+    [TestMethod]
+    public void CommandGetMapString()
+    {
+        // Test getting a parameter
+        var map = new YamlMappingNode { { "parameter", "Hello, ${{ name }}!" } };
+        var variables = new Dictionary<string, string> { { "name", "world" } };
+        Assert.AreEqual("Hello, world!", Command.GetMapString(map, "parameter", variables));
+    }
+}
\ No newline at end of file
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs b/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs
index f2ed20e..24312e2 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs
@@ -54,7 +54,7 @@ public void RunWorkflowFileInvalid()
 
             // Verify error reported
             Assert.AreEqual(1, exitCode);
-            Assert.IsTrue(output.Contains("Error: Workflow invalid.yaml invalid"));
+            Assert.IsTrue(output.Contains("Error: Workflow invalid.yaml missing steps"));
         }
         finally
         {
@@ -84,7 +84,7 @@ public void RunWorkflowMissingParameterInFile()
 
             // Verify error reported
             Assert.AreEqual(1, exitCode);
-            Assert.IsTrue(output.Contains("'help' command missing 'about' parameter"));
+            Assert.IsTrue(output.Contains("'help' command missing 'about' input"));
         }
         finally
         {
@@ -98,7 +98,8 @@ public void RunWorkflow()
     {
         const string fileContents = "steps:\n" +
                                     "- command: help\n" +
-                                    "  about: help\n";
+                                    "  inputs:\n" +
+                                    "    about: help\n";
 
         try
         {
@@ -124,4 +125,77 @@ public void RunWorkflow()
             File.Delete("help.yaml");
         }
     }
+
+    [TestMethod]
+    public void RunWorkflowWithDefaultParameters()
+    {
+        const string fileContents = "parameters:\n" +
+                                    "  about: help\n" +
+                                    "\n" +
+                                    "steps:\n" +
+                                    "- command: help\n" +
+                                    "  inputs:\n" +
+                                    "    about: ${{ about }}\n";
+
+        try
+        {
+            // Write the file
+            File.WriteAllText("help.yaml", fileContents);
+
+            // Run the workflow
+            var exitCode = Runner.Run(
+                out var output,
+                "dotnet",
+                "DemaConsulting.SpdxTool.dll",
+                "run-workflow",
+                "help.yaml");
+
+            // Verify success
+            Assert.AreEqual(0, exitCode);
+            Assert.IsTrue(
+                output.Contains("This command displays extended help information about the specified command"));
+        }
+        finally
+        {
+            // Delete the file
+            File.Delete("help.yaml");
+        }
+    }
+
+    [TestMethod]
+    public void RunWorkflowWithSpecifiedParameters()
+    {
+        const string fileContents = "parameters:\n" +
+                                    "  about: help\n" +
+                                    "\n" +
+                                    "steps:\n" +
+                                    "- command: help\n" +
+                                    "  inputs:\n" +
+                                    "    about: ${{ about }}\n";
+
+        try
+        {
+            // Write the file
+            File.WriteAllText("help.yaml", fileContents);
+
+            // Run the workflow
+            var exitCode = Runner.Run(
+                out var output,
+                "dotnet",
+                "DemaConsulting.SpdxTool.dll",
+                "run-workflow",
+                "help.yaml",
+                "about=to-markdown");
+
+            // Verify success
+            Assert.AreEqual(0, exitCode);
+            Assert.IsTrue(
+                output.Contains("This command produces a Markdown summary of an SPDX document"));
+        }
+        finally
+        {
+            // Delete the file
+            File.Delete("help.yaml");
+        }
+    }
 }
\ No newline at end of file