Intervals.icu MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions optional parameters with fallbacks to environment variables and date defaults, which is helpful. However, it doesn't describe authentication requirements, rate limits, error conditions, pagination, or what specific wellness data fields are returned. For a read operation with no annotation coverage, this leaves significant gaps.

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 with a clear purpose statement followed by organized parameter documentation. Each parameter explanation is efficient and informative. The only minor improvement would be integrating the parameter explanations more seamlessly rather than using a separate 'Args:' section.

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 that an output schema exists, the description doesn't need to explain return values. However, for a tool with 4 parameters, 0% schema description coverage, and no annotations, the description does well on parameters but lacks behavioral context about authentication, rate limits, and error handling. It's adequate but has clear gaps in operational guidance.

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%, so the description must fully compensate. It provides complete parameter documentation: all 4 parameters are clearly explained with their purposes, optional status, fallback behaviors, and format requirements. The description adds substantial value beyond the bare schema by explaining the .env fallback mechanism and date defaults.

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's purpose: 'Get wellness data for an athlete from Intervals.icu'. It specifies the verb ('Get'), resource ('wellness data'), and source ('Intervals.icu'), but doesn't differentiate from sibling tools like 'get_activities' or 'get_events' that also fetch data from the same platform.

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?

No guidance is provided on when to use this tool versus alternatives. The description doesn't mention sibling tools like 'get_activities' or explain what makes wellness data distinct from other data types available through the API. Usage context is implied but not explicitly stated.

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