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

Annotations already indicate readOnlyHint, openWorldHint, and non-destructive behavior. The description adds useful context: it is an aggregate/rollup call ('one call instead of twenty'), works across all websites, includes never-scanned and overdue counts, and requires the ENTERPRISE plan. No contradiction with annotations.

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 sentences, each earning its place: when to use, what data comes back, and plan/read-only status. It is front-loaded with the primary use case and contains 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 covers the main return elements: per-site scores, average, and counts for unscanned/overdue sites. It is complete enough for a zero-parameter rollup tool, though it does not specify exact response formatting or mention the 'finding counts' from the title explicitly.

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 and the schema coverage is 100%, so there is no parameter-level burden on the description. The description adds value by explaining what the result contains, which is sufficient for a no-parameter tool.

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 description clearly states what the tool does: returns the last recorded score for every website in the organisation, the average, and counts of unscanned or overdue sites. It also distinguishes itself from per-site tools by framing the scope as 'the whole portfolio rather than one site'.

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?

It explicitly says when to use it: for whole-portfolio accessibility questions, exec/board summaries, or identifying unscanned sites. It also gives a when-not signal ('rather than one site'), though it does not name a specific alternative sibling tool.

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