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

Annotations declare destructiveHint=true and idempotentHint=false, and the description corroborates the destructive path by explaining that an empty string clears a field, plus it discloses cost ("Free."), auth requirements, and the return value. It does not explain why the operation is flagged destructive or whether there is any confirmation/undo, so it adds context without fully covering the annotation's warning.

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?

The mutation semantics and field list are front-loaded, then invocation guidance, cost, and auth follow in short sentences with little waste. The one-word "Free." fragment is slightly abrupt but still informative rather than 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?

For a flat four-parameter update with no nesting and no output schema, the description covers purpose, partial-update behavior, clearing semantics, auth, cost, and the return value ("Returns the updated profile"). Nothing needed to invoke it correctly is missing.

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 and all four fields are already documented in the schema. The description adds the clearing rule ("an empty string clears a text field") and the send-only-changed-fields convention, which is real value beyond the schema, but nothing about the enum locale beyond restating what schema covers — netting a solid baseline rather than a lift.

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?

"Sets the account's name, company, use case ... and language" names a specific verb and enumerates the exact resource fields, so the agent knows precisely what is mutated. The only gap is sibling differentiation: it never contrasts itself with the adjacent update_email_preferences or get_account tools, which an agent might reasonably confuse given the overlapping 'language for emails' phrasing.

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?

"Send only the fields to change" gives explicit partial-update invocation guidance, and "Needs an API key or a connected account" states the prerequisite. It stops short of when-not-to-use guidance or naming alternatives, such as routing locale changes to update_email_preferences instead.

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