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

With no annotations provided, the description carries the full disclosure burden and does reasonably well: it lists the four result values an agent should expect and explicitly states that missing inputs fall back to documented defaults. For a pure computation tool this covers the meaningful behavioral surface, though error handling and edge cases are not addressed.

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?

Two sentences with the run instruction and output summary front-loaded. The semicolon-delimited output list is slightly choppy, but every clause earns its place and nothing is redundant.

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?

Despite 8 optional parameters, no output schema, and no annotations, the description covers the expected outputs and default-fallback behavior, so an agent can safely invoke it. It falls short by not addressing when to select it over 'calculator_describe' or how the 'roughly per month' figure is derived.

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 baseline of 3 applies: every parameter is already documented with types, enums, and defaults. The description only gestures at parameters through 'your choices' and adds no syntactic or format detail beyond the schema.

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?

States a specific verb ('Run') and resource (the annuity income calculator), and enumerates four concrete outputs the call produces, so an agent knows exactly what the tool does. It does not explicitly differentiate from the sibling 'calculator_describe', but the run-vs-describe distinction is strongly implied by the wording.

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?

Usage is implied: run this calculator to see income before and after applying choices. However, the description never states when to prefer this tool over 'calculator_describe' or the enquiry siblings, and it provides no exclusions or alternative routing.

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