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

Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true, so the mutation profile is covered structurally. The description adds the valuable partial-update semantic (only present fields change), but says nothing about what an update destroys or overwrites, which matters for a destructive-hinted tool.

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 with no filler, and the core update action plus the partial-update rule are front-loaded. It is efficient, though the middle fragment ('Writable fields of a site.') is a label rather than a full sentence.

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 15-parameter tool with nested objects and no output schema, the description is thin: it never explains interactions between fields (e.g. limits, schedule, device splits) or the effect on unspecified fields beyond the PATCH hint. Annotations cover safety, so it is minimally viable rather than 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?

Schema description coverage is 100% across 15 parameters, so the schema carries the field-level meaning. The description only adds the generic 'writable fields' framing and the PATCH rule, which is baseline-level value rather than compensating for gaps.

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 ('Update a site') that distinguishes it from the many other update_* siblings, and the second sentence scopes it to writable fields. However, it does not distinguish it from sibling operations on the same resource (e.g. delete_site, restore_site) beyond the verb itself.

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?

'For PATCH, provide at least one; only the fields present are changed' gives an implied usage rule for partial updates. It offers no guidance on when to use this versus create_site, restore_site, or get_site, so alternatives and preconditions are left to inference.

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