cronometer-mcp

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 states the tool returns specific statistics, implying a read-only operation, but doesn't clarify if it requires authentication, has rate limits, or how data is sourced (e.g., time range, user-specific). For a tool with zero annotation coverage, this is insufficient to fully inform an agent.

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 extremely concise and well-structured, using two sentences: one to state the purpose and another to list the returned data. Every word adds value without redundancy, making it easy for an agent to parse and understand quickly.

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 (0 parameters, output schema exists), the description is reasonably complete. It specifies the source (Cronometer) and the key statistics returned, which complements the output schema. However, it lacks behavioral context like authentication needs, which slightly reduces completeness for a tool with no 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 input schema has 0 parameters with 100% coverage, so no parameter documentation is needed. The description appropriately doesn't add parameter details, focusing instead on the output semantics by listing the returned statistics. This aligns with the baseline expectation for zero-parameter tools.

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 with the verb 'Get' and resource 'aggregate fasting statistics from Cronometer', specifying what data is retrieved. It distinguishes from siblings like 'get_fasting_history' by focusing on aggregated statistics rather than historical records. However, it doesn't explicitly contrast with all siblings, keeping it at a 4.

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. It doesn't mention when to choose this over 'get_fasting_history' or other data retrieval tools, nor does it specify prerequisites or context for use. This lack of usage instructions limits its effectiveness for an AI agent.

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