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

The annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds useful behavioral context: it supports pagination via limit and offset, states the data source (European Parliament Open Data API v2) and licensing (CC BY 4.0), and confirms no authentication is required. These details go beyond the annotations and help the agent understand the operational characteristics.

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 is well-structured and front-loaded with the core purpose, followed by filters, output fields, pagination, and data source. It uses concise sentences without unnecessary fluff. While it is longer than the absolute minimum, every sentence provides value, and the organization is logical. A slight deduction for not being the leanest possible, but it remains efficient.

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?

The description is complete for a read-only list tool. It covers the resource scope, all filters, the output fields, pagination behavior, data source, licensing, and authentication. It also connects to the sibling tool for next steps. With an output schema present, it doesn't need to detail the return format further, and the description adequately covers all aspects an agent needs to invoke it 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?

The schema provides 100% coverage with detailed descriptions for all six parameters, including enums for gender and political_group, plus limits and defaults. The description reinforces the filters and pagination but does not add new meaning beyond what the schema already states. The baseline of 3 is appropriate when the schema carries the parameter documentation load.

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 explicitly states the verb 'List' and the resource 'Members of the European Parliament (MEPs)', and details the scope ('currently serving in the active parliamentary term'). It clearly differentiates from the sibling meps.details by noting that the returned identifier is used with that tool for full history. This is a specific, well-defined purpose that an agent can immediately act on.

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 explicitly names the alternative tool (meps.details) and the condition for using it: 'Use the returned identifier with the meps.details tool to fetch the full membership history.' It also enumerates the available filters (country, political group, gender) and pagination, giving clear context for when this tool is appropriate. This is explicit guidance on when to use this tool versus the sibling.

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