Koleo MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It discloses the authentication requirement and hints at the data structure ('actual vs scheduled times'). However, it omits details about real-time data freshness, error handling for invalid train IDs, or rate limiting that would be valuable for a real-time data tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description consists of two efficient sentences with zero waste. The primary function is front-loaded in the first sentence, while the second sentence provides necessary operational context (authentication). Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has only two simple parameters and an output schema exists, the description provides a minimally viable foundation. However, the complete lack of parameter documentation and absence of behavioral details beyond authentication leaves notable gaps for an agent trying to invoke the tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, requiring the description to compensate. While 'for a train' loosely implies the train_id parameter, the operating_day parameter is completely undocumented. The description fails to explain what format operating_day expects (ISO date? YYYY-MM-DD?) or its purpose, leaving a significant gap given the schema provides no descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool retrieves a 'realtime timetable for a train' and specifies the key data returned ('actual vs scheduled times'). The 'realtime' qualifier helps distinguish it from sibling tools like tool_get_train_calendar or tool_get_train_route, though it doesn't explicitly name these alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description identifies one prerequisite ('Requires authentication in config'), which is useful usage guidance. However, it lacks explicit guidance on when to use this versus similar timetable tools (tool_get_train_calendar, tool_get_train_route) or how to handle the optional operating_day parameter.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.