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

Annotations already cover read-only, non-destructive and open-world, so the bar is lower; the description still adds two things annotations cannot: agency-key-only authorization and the non-obvious server-side default that start_date silently becomes today. It doesn't mention pagination behavior, though the schema carries next_page.

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?

Three short clauses plus an endpoint reference; the authorization constraint is front-loaded and the critical start_date gotcha follows immediately. No filler.

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?

With no output schema, the description usefully names the returned fields and covers scope, auth, and date filtering. Minor gap: nothing about paging through results beyond the schema's own page/per_page descriptions.

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 baseline is 3; the description adds genuine semantic meaning by saying start_date/end_date filter on creation date and flagging the today-default trap, which is the main way a caller would silently get an empty result.

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 ('list WhatConverts users') and scopes it ('of the master account or of client accounts'), plus the returned fields (email, role, activation pending). It never names the sibling single-user tool whatconverts_get_user, so differentiation is implied rather than explicit.

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?

Gives a real prerequisite ('Agency key only') and a concrete usage instruction: pass an early start_date because WhatConverts defaults it to today. It stops short of naming alternatives (e.g. whatconverts_get_user for a single user) or stating when not to use it.

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