yazio-mcp

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the agent knows this is a safe, repeatable read operation. The description adds minimal behavioral context by specifying the date/date range scope, but doesn't disclose other traits like rate limits, authentication needs, or what specific exercise data is returned. With annotations covering safety, a 3 is appropriate as the description adds some value but not rich behavioral details.

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 a single, efficient sentence that front-loads the core purpose without unnecessary words. Every part of the sentence earns its place by specifying the action, resource, and scope, making it appropriately sized for a simple tool.

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 low complexity (1 parameter, no output schema, simple annotations), the description is adequate but has gaps. It covers the basic purpose and scope, but lacks usage guidelines, detailed behavioral context beyond annotations, and clarification on date range handling. For a read-only tool with good annotations, it meets minimum viability but could be more complete.

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 100%, with the parameter 'date' fully documented in the schema as a date in YYYY-MM-DD format. The description mentions 'date or date range' but doesn't clarify how to specify a range (e.g., if multiple dates or a start/end are supported), adding only marginal semantic value beyond the schema. Baseline 3 is correct when the schema handles most parameter documentation.

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 action ('Get') and resource ('user exercise data') with scope ('for a date or date range'), making the purpose immediately understandable. However, it doesn't explicitly distinguish this tool from sibling tools like 'get_user_daily_summary' or 'get_user_goals' that might also involve user data retrieval, which prevents a perfect score.

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 like 'get_user_daily_summary' or 'get_user_goals', nor does it mention prerequisites or exclusions. It only states what the tool does, leaving the agent to infer usage context from the tool name alone.

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