yazio-mcp

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

Annotations indicate readOnlyHint=true and idempotentHint=true, which already inform the agent this is a safe, non-destructive read operation. The description adds no behavioral context beyond this, such as rate limits, authentication needs, or what 'weight data' entails (e.g., format, timestamps). Since annotations cover key safety aspects, the description meets a baseline but lacks added value like performance or error 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 'Get user weight data' is a single, clear sentence with no wasted words. It is front-loaded and efficiently conveys the core action, making it easy to parse. Given the simplicity of the tool, this conciseness is appropriate and effective.

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?

With no output schema, the description should ideally explain return values, but it does not. Annotations provide safety info, and the zero-parameter schema is fully covered. However, for a data retrieval tool, the description lacks details on what 'weight data' includes (e.g., numeric values, dates, units), making it incomplete for guiding the agent on expected outputs. It is minimally adequate given the low complexity.

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, meaning no parameters are documented in the schema. The description does not mention any parameters, which is appropriate here. It implies the tool might fetch weight data without inputs (e.g., for a default user), but does not clarify if this is user-specific or global. Baseline is 4 due to zero parameters, though it could hint at implicit context like user authentication.

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 'Get user weight data' restates the tool name 'get_user_weight' with minimal elaboration, making it tautological. It specifies the verb 'get' and resource 'user weight data' but lacks detail about what weight data includes (e.g., current weight, historical trends, units) or how it differs from siblings like 'get_user' or 'get_user_daily_summary'. This is vague and fails to distinguish from related tools.

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 does not mention context, prerequisites, or exclusions, such as whether it retrieves only the latest weight or a history, or if it should be used over 'get_user_daily_summary' for weight-specific data. This absence of usage instructions leaves the agent without direction.

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