Weblate MCP Server

Instructions

Implementation Reference

• src/tools/languages.tool.ts:12-47 (handler)

  The main handler function for the 'listLanguages' MCP tool. It uses @Tool decorator specifying name, description, input schema with Zod, fetches languages via service, formats as markdown list, handles errors, and returns structured content.

  @Tool({
    name: 'listLanguages',
    description: 'List languages available in a specific project',
    parameters: z.object({
      projectSlug: z.string().describe('The slug of the project'),
    }),
  })
  async listLanguages({ projectSlug }: { projectSlug: string }) {
    try {
      const languages = await this.weblateApiService.listLanguages(projectSlug);
  
      return {
        content: [
          {
            type: 'text',
            text: `Languages in project "${projectSlug}":\n\n${languages
              .map(
                (l) =>
                  `- **${l.name}** (${l.code})`,
              )
              .join('\n')}`,
          },
        ],
      };
    } catch (error) {
      this.logger.error(`Failed to list languages for ${projectSlug}`, error);
      return {
        content: [
          {
            type: 'text',
            text: `Error listing languages for project "${projectSlug}": ${error.message}`,
          },
        ],
        isError: true,
      };
    }

• src/tools/languages.tool.ts:15-17 (schema)

  Zod schema defining the input parameters for the listLanguages tool: projectSlug as string.

  parameters: z.object({
    projectSlug: z.string().describe('The slug of the project'),
  }),

• src/app.module.ts:74-80 (registration)

  Registration of tool classes including WeblateLanguagesTool in the AppModule providers. Since they use @Tool decorator, NestJS/MCP auto-registers them.

    WeblateProjectsTool,
    WeblateComponentsTool,
    WeblateLanguagesTool,
    WeblateTranslationsTool,
    WeblateChangesTool,
    WeblateStatisticsTool,
  ],

• src/services/weblate-api.service.ts:43-45 (helper)

  Helper method in WeblateApiService that delegates listLanguages call to the underlying languages service.

  async listLanguages(projectSlug: string): Promise<Language[]> {
    return this.languagesService.listLanguages(projectSlug);
  }

• src/services/weblate/languages.service.ts:11-44 (helper)

  Core helper service implementing the API call to retrieve languages for a project using Weblate client, with response parsing and error handling.

  async listLanguages(projectSlug: string): Promise<Language[]> {
    try {
      const client = this.weblateClientService.getClient();
      const response = await projectsLanguagesRetrieve({
        client,
        path: { slug: projectSlug }
      });
      
      // Handle different response formats
      const languages = response.data as any;
      
      if (Array.isArray(languages)) {
        return languages;
      }
      
      // If it's a paginated response
      if (languages && languages.results && Array.isArray(languages.results)) {
        return languages.results;
      }
      
      // If it's a single language, wrap it in an array
      if (languages && typeof languages === 'object') {
        return [languages];
      }
      
      return [];
    } catch (error) {
      this.logger.error(
        `Failed to list languages for project ${projectSlug}`,
        error,
      );
      throw new Error(`Failed to list languages: ${error.message}`);
    }
  }