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 valuable behavioral context by stating it returns 'a clock-style breakdown and decimal hours', which is not present in the schema or annotations. It does not mention edge cases or rounding behavior, but for a pure converter this is acceptable.

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 three sentences, front-loaded with the core action, and every sentence earns its place. It states what it does, how to invoke it, and what the output will be, without unnecessary filler. The source URL is a minor addition but does not bloat the text.

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 description is complete enough for a simple two-mode converter: it covers both directions, mentions the optional extra minutes, and hints at the return format. An output schema exists, so return values don't need detailed explanation here. It could mention that for 'hoursToMinutes' the 'hours' and 'extraMinutes' parameters are optional with defaults, but the schema already conveys that.

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 100%, so the schema already documents all parameters and their meanings. The description restates the mode values and the role of extra minutes, but it doesn't add significant new meaning beyond what the schema provides. The baseline of 3 is appropriate.

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 function: converting minutes to hours/minutes or hours to total minutes, with two explicit modes. It names the specific resource (minutes/hours) and the verb 'convert', making it easy to understand. However, it does not explicitly differentiate from sibling tools like hopi_hours_calculator or hopi_time_calculator, so it stops short of a 5.

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 when to use the tool—whenever a minutes-to-hours or hours-to-minutes conversion is needed—by explaining the two modes. It gives direct instructions on setting the 'mode' parameter, but it does not provide explicit guidance on when not to use this tool or how it differs from alternatives. No exclusions or alternative recommendations are mentioned.

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