cronometer-mcp

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the read-only nature (implied by 'Get' and 'Returns'), data scope, and optional date filtering. However, it lacks details on permissions, rate limits, pagination, error conditions, or whether the operation is idempotent—important for a tool with no annotation coverage.

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 front-loaded with the core purpose, followed by return details and parameter explanations in a structured 'Args' section. Every sentence earns its place—no redundant or vague statements. It's appropriately sized for a tool with two simple parameters.

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 (2 optional parameters), no annotations, but presence of an output schema, the description is mostly complete. It covers purpose, usage context, and parameter semantics adequately. The output schema will handle return value documentation, so the description doesn't need to detail response structure. However, it could better address behavioral aspects like error handling or data freshness.

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 compensate. It adds meaningful semantics by explaining that start_date and end_date are optional (omit for all history), specifies the format (YYYY-MM-DD), and clarifies their role in filtering the date range. This goes beyond the schema's basic type and title information, though it doesn't detail validation rules or timezone handling.

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 specific verbs ('Get fasting history') and resource ('from Cronometer'), distinguishing it from siblings like 'get_fasting_stats' (which likely provides aggregated statistics rather than historical records) and 'cancel_active_fast' (which modifies rather than retrieves data). It specifies the scope of data returned (fasts with status, names, recurrence rules, timestamps).

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 clear context for usage by explaining that it returns 'all fasts (or fasts within a date range)', with date parameters being optional. However, it does not explicitly state when to use this tool versus alternatives like 'get_fasting_stats' or 'get_daily_nutrition', nor does it mention any prerequisites or exclusions for use.

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