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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false. The description adds merge semantics beyond those hints: omitted fields are preserved (or blank for a new profile) and custom_field is merged key-by-key, which tells the agent how partial updates behave.

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, front-loaded with the upsert action, then the update semantics, then the multi-profile context. 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, a nested `field` object, and a destructive annotation, the description supplies the needed merge/partial-update behavior and notes that multiple named profiles can coexist. It leaves the destructive aspect implicit, but the practical calling guidance is 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 coverage is 100%, so the baseline is 3, but the description adds real meaning: the partial-update contract for `field` and the key-by-key merge for custom_field go beyond the schema's generic 'omitted fields keep their current value' note.

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 pair (creates or updates) plus the resource (one named site profile) and scopes it to this account. An agent can distinguish it from the sibling get_siteprofile at a glance.

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?

Gives clear call guidance: pass only what changed, omitted fields retain saved values, and custom_field entries merge key-by-key. It does not explicitly say when to prefer this over get_siteprofile, but the read/write split is obvious from the verb.

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