diff --git a/src/utils/actions/action-parameter-type-descriptor.ts b/src/utils/actions/action-parameter-type-descriptor.ts
new file mode 100644
index 0000000..97df952
--- /dev/null
+++ b/src/utils/actions/action-parameter-type-descriptor.ts
@@ -0,0 +1,157 @@
+import { QueryString } from "@/utils/net";
+import { ImportDirective, parseImportDirective } from "@/utils/reflection";
+
+/**
+ * Represents a type of a parameter of a GitHub Action.
+ */
+export interface ActionParameterTypeDescriptor extends ImportDirective {
+    /**
+     * Indicates whether the type should be treated as an array.
+     */
+    isArray: boolean;
+
+    /**
+     * A factory function able to create a new instance of the this type.
+     */
+    factory?: ImportDirective;
+
+    /**
+     * Options for the factory function.
+     *
+     * Known values include:
+     * - `split` (boolean) - Determines if the input string should be split into an array of strings.
+     * Defaults to `true` if this type represents an array, and `false` otherwise.
+     *
+     * - `separator` (RegExp) - If `split` is `true`, this is used to divide the input string into an array of strings.
+     * Otherwise, it's unused. Default value is `/\r?\n/g`.
+     *
+     * - `processSeparately` (boolean) - If `split` is set to `true`, this indicates whether the factory/converter function
+     * should accept the input array as a whole or process its values individually and then concatenate them into a new array.
+     * Default value is the same as `split`.
+     *
+     * - `trimEntries` (boolean) - If `true`, trims whitespace from the beginning and end of each entry in the array.
+     * Default value is the same as `split`.
+     *
+     * - `removeEmptyEntries` (boolean) - If `true`, removes empty entries from the array after processing.
+     * Default value is the same as `split`.
+     *
+     * - `flatDepth` (number) - The depth level specifying how deep a nested array structure should be flattened.
+     * Passes the value to Array.prototype.flat() method. Default value is `1`.
+     */
+    options?: QueryString;
+}
+
+/**
+ * Parses a string into a type descriptor of a parameter of a GitHub Action.
+ *
+ * @param descriptor - The type descriptor to parse.
+ *
+ * @returns An {@link ActionParameterTypeDescriptor} object, or `undefined` if the input was invalid.
+ *
+ * @example
+ *
+ * ```
+ * parseActionParameterTypeDescriptor("foo/bar-bar/baz-baz->{BazBaz}:{parseBazBaz}?key=value");
+ * ```
+ */
+export function parseActionParameterTypeDescriptor(descriptor: string): ActionParameterTypeDescriptor | undefined {
+    if (!descriptor) {
+        return undefined;
+    }
+
+    // Remove all whitespace characters and generics from the descriptor.
+    descriptor = descriptor.replaceAll(/\s/g, "").replaceAll(/<.*>/g, "");
+
+    const isArray = descriptor.includes("[]");
+    descriptor = descriptor.replaceAll("[]", "");
+
+    const optionsIndex = descriptor.indexOf("?");
+    const options = optionsIndex >= 0 ? QueryString.parse(descriptor.substring(optionsIndex)) : undefined;
+    descriptor = optionsIndex >= 0 ? descriptor.substring(0, optionsIndex) : descriptor;
+
+    const normalizedDescriptor = normalizePattern(descriptor);
+    const [type, factory] = normalizedDescriptor.split(";").map(parseImportDirective);
+
+    return { ...type, factory, options, isArray };
+}
+
+/**
+ * Normalizes a type descriptor pattern for use in an action signature.
+ *
+ * @param descriptor - The type descriptor pattern to normalize.
+ *
+ * @returns The normalized type descriptor pattern.
+ *
+ * @example
+ *
+ * ```
+ * "foo/bar-bar/baz-baz->{BazBaz:parseBazBaz}" => "foo/bar-bar/baz-baz->{BazBaz};parseBazBaz"
+ * "foo/bar-bar/baz-baz->{BazBaz}:{parseBazBaz}" => "foo/bar-bar/baz-baz->{BazBaz};foo/bar-bar/baz-baz->{parseBazBaz}"
+ * "foo/bar-bar/baz-baz->{BazBaz}:parseBazBaz" => "foo/bar-bar/baz-baz->{BazBaz};foo/bar-bar/baz-baz->parseBazBaz"
+ * "foo/bar-bar/baz-baz->BazBaz:{parseBazBaz}" => "foo/bar-bar/baz-baz->BazBaz;foo/bar-bar/baz-baz->{parseBazBaz}"
+ * "foo/bar-bar/baz-baz->BazBaz:parseBazBaz" => "foo/bar-bar/baz-baz->BazBaz;parseBazBaz"
+ * ```
+ */
+function normalizePattern(descriptor: string): string {
+    if (!descriptor.includes("/") && descriptor.includes(".")) {
+        return normalizePatternInDotNotation(descriptor);
+    }
+
+    if (!descriptor.includes(":")) {
+        return descriptor;
+    }
+
+    const descriptors = descriptor.split(";");
+    const mainDescriptor = descriptors[0];
+    if (!mainDescriptor.includes(":")) {
+        return mainDescriptor;
+    }
+
+    const typeDescriptor = mainDescriptor.replaceAll(/:(?:\w+|{\w+})/g, "");
+    const typeModule = mainDescriptor.match(/^.*->/)?.[0];
+    const match = mainDescriptor.match(/\{?(?<type>\w+)(?<isTypeImported>\}?):(?<isFactoryImported>\{?)(?<factory>\w+)\}?/)?.groups;
+    const factoryModule = !match.isTypeImported && !match.isFactoryImported ? "" : typeModule;
+    const factoryDescriptor = factoryModule + (match.isFactoryImported ? `{${match.factory}}` : match.factory);
+    return `${typeDescriptor};${factoryDescriptor}`;
+}
+
+/**
+ * Converts a type descriptor in dot notation to slash notation.
+ *
+ * @param descriptor - The type descriptor in dot notation.
+ *
+ * @returns The type descriptor in slash notation.
+ *
+ * @example
+ *
+ * ```
+ * "foo.barBar.BazBaz" => "foo/bar-bar/baz-baz->{BazBaz}"
+ * "foo.barBar.BazBaz:parseBazBaz" => "foo/bar-bar/baz-baz->{BazBaz};parseBazBaz"
+ * "foo.barBar.BazBaz:{parseBazBaz}" => "foo/bar-bar/baz-baz->{BazBaz};foo/bar-bar/baz-baz->{parseBazBaz}""
+ * ```
+ */
+function normalizePatternInDotNotation(descriptor: string): string {
+    const descriptors = descriptor.split(";");
+    const dotDescriptor = descriptors[0];
+
+    // Use a regular expression to match the path, name, and factory components of the descriptor.
+    const match = dotDescriptor.match(/^(?<path>.*?\.)?(?<name>[\w]+?)(?::(?<factory>{?\w+}?))?$/);
+    if (!match) {
+        return descriptor;
+    }
+
+    const path = match.groups.path;
+    const typeName = match.groups.name;
+
+    // Create the full path by replacing dots with slashes and converting camelCase to kebab-case.
+    const fullPath = path && `${path}${typeName}`.replaceAll(".", "/").replaceAll(/([a-z])([A-Z])/g, "$1-$2").toLowerCase();
+
+    const factoryName = match.groups.factory;
+    const isFactoryImported = factoryName?.charAt(0) === "{";
+    const typeDescriptor = fullPath ? `${fullPath}->{${typeName}}` : typeName;
+    const factoryDescriptor = factoryName ? isFactoryImported && fullPath ? `${fullPath}->${factoryName}` : factoryName : descriptors[1];
+
+    // Join the type and factory descriptors (if any) with semicolons and return as the result.
+    const slashDescriptor = [typeDescriptor, factoryDescriptor].filter(x => x).join(";");
+    return slashDescriptor;
+}