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

Annotations only provide idempotentHint, so the description carries most of the behavioral burden and does add real value by declaring write semantics and partial-update behavior. It omits permissions needed, whether a field can be cleared (omitted vs. nulled), error behavior when sid doesn't exist, and the response shape.

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, front-loaded clauses with the WRITE marker first and zero filler. The trailing 'API: PUT /site' is mildly redundant but cheap and useful for API parity.

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 20-parameter mutation with no output schema and half the fields undescribed, the description should explain the sid anchor, allowed/ignored fields, and the return behavior. It leaves the majority of the calling surface undocumented.

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?

20 parameters with only 50% schema description coverage; the description contributes nothing about any field. Several params (uid, uid2, zip, beds, city, state, garage, lotsize, yearbuilt, baths) are undocumented in both the schema and the description, so an agent has no guidance on the biggest area of ambiguity.

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 ('update'), resource ('existing property site'), and marks it as a WRITE operation, which cleanly separates it from hdphotohub_create_site and the read siblings like get_site/list_sites. It does not explicitly distinguish itself from hdphotohub_set_site_status, the other site-mutating sibling.

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?

'Only the fields you pass change' implies when this is appropriate (partial edits) versus a full replace, but no exclusion or alternative is named. An agent must infer that status changes belong to set_site_status and full creation to create_site.

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