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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the operation (addition) and the output format (hours and minutes), but does not address potential edge cases like overflow (e.g., minutes exceeding 59) or whether the tool handles carry-over. For a simple additive tool, the description is adequate but lacks depth.

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 consists of two concise sentences that front-load the primary purpose and then efficiently direct users to related tools. Every word serves a purpose, with no redundancy or unnecessary detail.

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?

Given the tool's simplicity (four parameters, straightforward addition) and the presence of an output schema (not shown but noted as present), the description is nearly complete. It states the output in hours and minutes, but could briefly mention that minutes are constrained to 0-59 and that carry-over is handled. Overall, it covers the essential context.

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 100% description coverage for all four parameters (hours1, minutes1, hours2, minutes2), making the schema self-sufficient. The description adds no extra meaning beyond what the schema provides, so the baseline score 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: 'Add two time durations and return the total in hours and minutes.' It uses specific verbs and resources, and the mention of 'list_bundles' for related 'temps-rh' calculators distinguishes it from sibling tools. The purpose is unambiguous and well-defined.

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 a hint by referencing 'list_bundles' for related calculators, implying that other time-related operations may be available there. However, it does not explicitly state when to use this tool versus alternatives (e.g., for subtraction, conversion, or more complex duration arithmetic). The guidance is minimal and could be improved by clarifying its specific scope.

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