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

No annotations are provided, so the description carries the burden of behavioral disclosure. It indicates that the tool provides descriptive information about calculator inputs, outputs, and assumptions, which suggests a read-only metadata operation. However, it does not explicitly state that no calculation is performed or that no side effects occur, which would improve clarity.

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 a single concise sentence that lists the three key content areas: inputs, outputs, and assumptions/tables. It contains no filler, though it is grammatically a sentence fragment rather than a complete statement with a main verb.

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 zero-parameter describe tool with no output schema, the description covers the main aspects an agent would want to know: inputs with units/ranges/defaults, outputs, and assumptions/tables. It is nearly complete, though an explicit note that this tool does not perform the calculation itself would fully close the loop with the 'calculate' sibling.

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 tool has zero parameters, so the description is not required to document any. The mention of calculator inputs refers to the calculator being described, not to this tool's own parameters, so the 0-param baseline of 4 applies without needing additional detail.

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 title 'What Pub mortgage calculator computes' and description make clear this tool describes the calculator's inputs, outputs, and underlying assumptions. It is distinguishable from the sibling 'calculate' tool, which presumably performs the calculation, but the description itself lacks an explicit verb such as 'returns' or 'explains' and relies partly on the title for clarity.

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 this is the tool to use when an agent needs to know the calculator's inputs, defaults, outputs, or assumptions. However, it does not explicitly say when to use this instead of 'calculate' or any other sibling tool, leaving the usage context mostly implicit.

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