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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the unit list and source link but no extra behavioral traits such as rounding, precision, or error handling. With annotations covering the key behaviors, a 3 is appropriate.

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 one concise sentence followed by a list of units and a source URL. It front-loads the core purpose and contains no redundant or verbose phrasing. Every element earns its place.

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?

The tool is simple, has a complete input schema, and an output schema is present. The description provides the unit list and conversion intent; nothing else is needed for an agent to invoke it correctly. Source link adds minor provenance value.

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 coverage is 100% for all three parameters (value, from, to), including descriptions and enums. The description repeats the unit list from the schema without adding new semantics like formatting, precision, or edge cases. Baseline 3 is correct when the schema carries the parameter details.

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 states a specific verb and resource ('Convert a volume from one unit to another') and lists all supported units. The tool name and title reinforce the action. It is clearly distinct from other converter tools by specifying the volume domain.

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 when to use the tool (volume conversions) but does not explicitly mention alternatives or exclusions. Sibling converters exist (e.g., litres_to_pints, length_converter), but the domain is obvious from the name and description.

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