mfp_set_measurement

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

Annotations already indicate mutation (readOnlyHint=false) and non-idempotency (idempotentHint=false). The description adds valuable context: it logs a 'new' measurement (implying each call appends), specifically 'for today', and returns a confirmation message. It does not disclose potential duplicate behavior or unit nuances, but the key behavioral traits are conveyed.

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 concise and front-loaded with the primary purpose in the first sentence. It includes a structured Args and Returns section, but the Args block largely duplicates schema information. It wastes no words and is appropriately sized for a simple tool.

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?

For a tool with only two parameters and good annotations, the description is complete: it states the action, scope ('for today'), parameters, and return type. It lacks explicit accepted measurement types or units, but the schema covers those examples. No critical information appears missing for correct invocation.

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 description explicitly breaks down the nested 'params' object, listing both 'measurement' (with type and default) and 'value' (with type and example). While the schema already provides descriptions for these sub-parameters, the top-level schema coverage is 0% and the description compensates by clarifying the nested structure, default, and example values, adding meaning for agents unfamiliar with the schema.

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 uses a specific verb+resource ('Log a new body measurement') and clearly differentiates from siblings like mfp_get_measurements (read) and mfp_set_goals (set goals). The scope 'for today' adds precision, making the tool's purpose immediately clear.

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 implies usage: if you need to log a measurement for today, use this tool. However, it does not explicitly mention alternatives (e.g., mfp_get_measurements for retrieving measurements) or provide when-not-to-use guidance. The phrase 'for today' hints at a constraint but no exclusions are stated.

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