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

Annotations already declare this is not read-only, is idempotent, and is destructive. The description adds useful auth context with 'Requires sites:write scope,' but it does not explain partial-update semantics, what happens to omitted fields, or how destructive the operation may be beyond the annotation hint.

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, front-loaded with the core action and followed by the prerequisite scope. There is no wasted language.

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?

Given a 28-parameter update tool, the description is minimal. It covers purpose and authorization, and annotations cover safety, but it leaves out whether this is a full or partial update and what happens to omitted fields, which are important for correct invocation.

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 the schema documents all 28 parameters. The description only adds that the update is performed 'by ID,' which slightly reinforces the required id parameter but does not enrich field meanings or update semantics beyond the schema.

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 states a clear verb+resource: 'Update an existing site by ID.' It distinguishes this from its many siblings by resource (site vs. building, system, etc.), though it does not explicitly name an alternative or clarify scope beyond 'existing 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 gives the required auth scope ('Requires sites:write scope') and implies the site must already exist, but it does not say when to use this tool versus alternatives such as create_site, delete_site, or update_building, nor does it give exclusions.

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