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

readOnlyHint=true already declares this is a safe read, so the burden is lower. The description adds genuine value by enumerating the returned fields (category, type, total), which matters because there is no output schema. It does not mention pagination behavior or result ordering, but the schema covers the paging parameters.

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 with the purpose and returned fields front-loaded and no filler. The raw endpoint reference is minor redundancy but arguably useful for debugging.

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, non-destructive list tool, the description covers what it returns and what it lists; paging is fully documented in the schema and safety in annotations. Only the absence of guidance on ordering or typical result volume keeps it from a 5.

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%: both page and per_page document defaults and maximums directly in the schema. The description adds nothing about parameters, so the baseline 3 applies.

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 (List) and resource (reusable fees saved on the account), and adds the returned fields (category, type, total). The phrase 'saved on the account' distinguishes these reusable fee templates from proposal-attached fees, though it never names the sibling list_proposal_fees 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?

Usage is implied rather than stated: an agent can infer this is the fee-library listing, not the per-proposal fee listing, from 'reusable fees saved on the account'. There is no explicit when-to-use/when-not or named alternative, so the agent must reason about siblings.

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