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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds a source URL but does not disclose additional behavioral details such as rounding behavior or precision. There is no contradiction, but the description contributes little 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?

The description is two sentences, front-loads the core purpose, and lists the supported units compactly. The source URL is a minor extra but does not bloat the description. Every sentence serves a clear informative purpose.

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 simple, pure conversion tool with complete schema descriptions, full parameter enums, an output schema, and safety annotations, nothing essential is missing. The description, schema, and annotations together give the agent everything needed to select and invoke the tool correctly.

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 schema descriptions are fully present with enums, but the schema only says 'Unit to convert from/to' without expanding abbreviations. The description adds value by mapping g, kg, oz, lb, and st to grams, kilograms, ounces, pounds, and stone, which helps the agent understand the parameter values.

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 and resource: 'Convert a weight from one unit to another', followed by the exact supported units. This clearly identifies the tool as a general weight converter and implicitly distinguishes it from length, area, volume, and other converter siblings.

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 context is clear: use this tool for weight conversions among g, kg, oz, lb, and st. It does not explicitly mention alternatives like hopi_kg_to_stone or state when not to use the tool, but for a simple converter the usage conditions are evident and no exclusions are needed.

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