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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the safety profile is covered. The description adds two pieces of context the annotations cannot: a per-call credit cost and that results come back in descending order. It says nothing about edge cases such as n exceeding the list length or duplicate values.

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 short sentences, front-loaded with the operation and result ordering, with the cost note appended. Nothing is wasted and nothing needs to be re-read.

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 two-parameter read-only utility with full schema coverage and no output schema, the description supplies what matters: the operation, the result ordering, and the cost. Only edge-case behavior (n larger than list size, ties) is left unaddressed.

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%, so the baseline is 3; the description goes slightly beyond by tying n to 'largest' selection and clarifying that the input is a numeric list. It adds no interpretation of the string-typed schema fields, but the schema already documents both parameters.

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 and resource ('Finds the n largest numbers from a list') plus the ordering of results, which is enough to separate it from siblings like find_kth_smallest, sort_numbers, or average. It stops short of naming those alternatives explicitly.

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?

No guidance on when to choose this over the many adjacent numeric siblings (find_kth_smallest, sort_numbers, average). The use case is inferable from the description but no conditions, exclusions, or alternatives are stated.

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