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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered. The description adds context the annotations cannot: only *active* collections are returned, collections are sorted newest-first, and fields are grouped by collection in display order — all useful for interpreting results. Return format details and any size/limit behavior are still unstated.

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 sentences: what it returns, how the result is ordered, and when to use it. Scope is front-loaded and there is 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 and no annotation beyond the safety hints, the description does a good job sketching the return shape (collections ordered, fields grouped). It leaves open whether items or metadata (types, required flags, validation) are included and whether there are any size limits, so it is strong but not fully complete.

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 single parameter websiteId has 0% schema description coverage, so the description must carry the meaning. 'Of a website' implies websiteId scopes the snapshot, but it never states the expected ID format (slug vs. numeric vs. UUID) or how an invalid/foreign websiteId behaves. Marginal compensation for the coverage gap.

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 ('Returns') and resource ('every active collection and field of a website'), and characterizes the result as 'the full content model'. That is enough to distinguish it from the sibling cms_collections_* / cms_fields_* mutation tools without opening any schema.

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?

Explicitly says when to reach for it: 'to discover the schema before reading or writing items', which sets it up as the prerequisite step for the cms_items_* tools. It stops short of naming a competing alternative or an explicit when-not-to-use, so it lands at 4 rather than 5.

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