Polar MCP Capabilities

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description is not required to repeat those. It adds context by specifying the topics covered (Polar data, privacy boundaries, workflow, project links), which goes beyond the annotations.

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, 12 words, highly concise. Could be improved by listing topics more explicitly, but it's sufficiently clear and front-loaded.

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 is a meta capabilities overview, the description covers the key topics. An output schema exists to describe return values. The description is complete enough for its purpose.

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 only parameter (response_format) is self-explanatory from its enum and default, and the schema coverage is 0%, so the description should ideally mention it. However, the parameter is trivial and the default is 'markdown', so the lack of mention is a minor gap.

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?

Description clearly states it explains supported Polar data, privacy boundaries, recommended agent workflow, and project links. This distinguishes it from sibling tools that retrieve specific data types (e.g., polar_list_activity).

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?

Description implies use for understanding capabilities and workflow, but does not explicitly state when to use it vs. alternatives or when not to use it. No exclusions or alternative references are provided.

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