diff --git a/cmd/generate.go b/cmd/generate.go
new file mode 100644
index 0000000..9b9f1e5
--- /dev/null
+++ b/cmd/generate.go
@@ -0,0 +1,53 @@
+/*
+Copyright © 2021 Matt Rose <matthewrose153@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+
+	"github.com/matty-rose/gha-docs/pkg/parser"
+	"github.com/matty-rose/gha-docs/pkg/writer"
+)
+
+// generateCmd represents the generate command
+var generateCmd = &cobra.Command{
+	Use:   "generate [PATH]",
+	Short: "Generate documentation for a composite GitHub action.",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		action, err := parser.Parse(args[0])
+		if err != nil {
+			return errors.Wrap(err, "couldn't parse the action file")
+		}
+
+		doc := writer.Write(action)
+		fmt.Println(doc)
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(generateCmd)
+}
diff --git a/pkg/writer/writer.go b/pkg/writer/writer.go
new file mode 100644
index 0000000..63e8f20
--- /dev/null
+++ b/pkg/writer/writer.go
@@ -0,0 +1,67 @@
+/*
+Copyright © 2021 Matt Rose <matthewrose153@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+package writer
+
+import (
+	"strconv"
+
+	"github.com/matty-rose/gha-docs/pkg/formatter"
+	"github.com/matty-rose/gha-docs/pkg/types"
+)
+
+func Write(action *types.CompositeAction) string {
+	doc := formatter.NewMarkdownDocument()
+
+	doc.WriteHeading(action.Name, 1)
+	doc.WriteText(action.Description)
+	doc.WriteNewLine()
+
+	if len(action.Inputs) != 0 {
+		var inputs [][]string
+		for _, inp := range action.Inputs {
+			inputs = append(inputs, []string{inp.Name, inp.Description, strconv.FormatBool(inp.Required), inp.Description})
+		}
+
+		doc.WriteNewLine()
+		doc.WriteHeading("Inputs", 2)
+		_, _ = doc.WriteTable(
+			[]string{"Name", "Description", "Required", "Default"},
+			inputs,
+		)
+	}
+
+	if len(action.Outputs) != 0 {
+		var outputs [][]string
+		for _, out := range action.Outputs {
+			outputs = append(outputs, []string{out.Name, out.Description, out.Value})
+		}
+
+		doc.WriteNewLine()
+		doc.WriteHeading("Outputs", 2)
+		_, _ = doc.WriteTable(
+			[]string{"Name", "Description", "Value"},
+			outputs,
+		)
+	}
+
+	return doc.Render()
+}