Koleo MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It fails to indicate whether this is cached/static data, if there are rate limits, or auth requirements. The word 'List' implies read-only, but explicit safety/performance characteristics are absent.

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?

Single sentence with zero waste. The parenthetical examples are efficiently placed at the end to clarify domain terminology without bloating the core verb-resource statement.

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's simplicity (no inputs) and the presence of an output schema, the description is complete enough for invocation. It adequately covers the 'what' (carriers) but misses the 'how expensive/safe' aspects that would make it fully complete for an agent lacking annotations.

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?

The tool has zero parameters, which establishes a baseline score of 4 per the rubric. No parameter documentation is required.

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 uses a specific verb 'List' with clear resource 'train carriers' and concrete examples (PKP Intercity, POLREGIO) that implicitly distinguish it from siblings like tool_get_brands or tool_get_stations. However, it doesn't explicitly differentiate when to choose this over similar enumeration tools.

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 provides no guidance on when to use this tool versus alternatives, nor does it mention prerequisites or contextual triggers (e.g., 'use this before searching connections to filter by carrier').

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