Android Preference Editor MCP Server

Instructions

Implementation Reference

• src/tools/prefs.ts:18-50 (handler)

  Handler function executing the tool logic: validates input with EditPrefSchema, constructs PartialPreference from name and value, calls external changePreference, returns success or error message.

  async (input: z.infer<typeof EditPrefSchema>) => {
    try {
      validate(input, EditPrefSchema);
  
      const { name, value, ...connection } = input;
  
      const pref: PartialPreference = {
        value,
        key: name,
      };
  
      await changePreference(pref, connection);
  
      return {
        content: [
          {
            type: "text",
            text: `Preference changed`,
          },
        ],
      };
    } catch (error) {
      return {
        isError: true,
        content: [
          {
            type: "text",
            text: error instanceof Error ? error.message : "Unknown error",
          },
        ],
      };
    }
  }

• src/schema.ts:11-33 (schema)

  Schema definitions culminating in EditPrefSchema = PrefSchema.merge(FileSchema), providing input validation for name, value, filename, appId, deviceId.

  export const FileSchema = AppSchema.extend({
    filename: z.string().describe("The filename with or without the extension."),
  });
  
  export const NameSchema = z.object({
    name: z.string().describe("The name/key of the user preference"),
  });
  
  export const PrefSchema = NameSchema.extend({
    value: z.string().describe("The value of user preference"),
  });
  
  export const TypedPrefSchema = PrefSchema.extend({
    type: z
      .string()
      .describe(
        "The type of the preference value: integer, boolean, float, double, long or string"
      ),
  });
  
  export const AddPrefSchema = TypedPrefSchema.merge(FileSchema);
  
  export const EditPrefSchema = PrefSchema.merge(FileSchema);

• src/tools/prefs.ts:15-51 (registration)

  Registration of the change_preference tool using server.tool with name, description, EditPrefSchema.shape, and handler function.

    "change_preference",
    "Changes the value of an existing preference",
    EditPrefSchema.shape,
    async (input: z.infer<typeof EditPrefSchema>) => {
      try {
        validate(input, EditPrefSchema);
  
        const { name, value, ...connection } = input;
  
        const pref: PartialPreference = {
          value,
          key: name,
        };
  
        await changePreference(pref, connection);
  
        return {
          content: [
            {
              type: "text",
              text: `Preference changed`,
            },
          ],
        };
      } catch (error) {
        return {
          isError: true,
          content: [
            {
              type: "text",
              text: error instanceof Error ? error.message : "Unknown error",
            },
          ],
        };
      }
    }
  );

• src/index.ts:21-21 (registration)

  Top-level call to configurePreferenceTools(server), which registers the change_preference tool among others.

  configurePreferenceTools(server);