Vibie MCP has solid foundational structure with 4 well-named tools and complete JSON schemas. All tools follow verb_noun naming (vibie_create_site, vibie_update_site, vibie_list_sites, vibie_get_site). Descriptions are present and actionable for LLM selection (ranging 150-270 chars, within the 10-1024 baseline). Parameters have descriptions and types. However, output schemas are not documented, the response format is never formally declared, forcing LLMs to infer structure. Error handling is comprehensive (AuthRequiredError, ApiAuthError, ApiError) with recovery guidance, but error responses embed instructions rather than returning structured error codes. No parameter enums are used where appropriate (e.g., 'category' accepts freeform strings rather than a constrained list: portfolio/wedding/landing/event/game/photo/linkbio/misc). Missing validation documentation for path traversal in the 'folder' parameter. Overall: well-executed within its scope, but gaps in output documentation and input validation prevent a higher score.

• Document the response schema for each tool. For vibie_list_sites, specify: 'Returns a JSON object with fields: sites (array of {slug, name, category, url, visibility, lastUpdated}), total (count)'. For vibie_get_site, specify the single-site object structure. This allows LLMs to extract fields for chaining.
• Convert 'category' from a freeform string to an enum: ['portfolio', 'wedding', 'landing', 'event', 'game', 'photo', 'linkbio', 'misc']. Enums are self-documenting and prevent invalid LLM guesses.
• Add validation rules to 'folder': 'Must be an absolute or relative path to a directory. Paths are validated server-side for traversal attacks. Max path length 255 characters.'
• Implement tool annotations in the tool definition. Add to vibie_create_site and vibie_update_site: 'destructiveHint: true' to signal these are write operations that may trigger retries.
• Restructure error responses to return error codes + messages separately from recovery instructions. E.g. {error_code: 'AUTH_REQUIRED', message: 'Vibie authentication needed', recovery: {...}} so clients can handle them programmatically.
• Add pagination guidance to vibie_list_sites if the API supports it. Document: 'If the user has >50 sites, add limit and offset parameters to the schema, and return a next_cursor for pagination.'
• Document idempotency for vibie_update_site: 'This tool is idempotent, calling it multiple times with the same folder and note will produce identical results, making it safe for agent retries.'