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

The description adds substantial behavior beyond the annotations: daily digest cadence, that only new entries trigger emails, that site_name null clears the value, and detailed return statuses for email deliverability and digest scheduling. It matches the mutation/destructive annotations without contradicting them.

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 description is front-loaded with the purpose and the details generally earn their place, including return-value context since no output schema exists. It is dense and uses nested parentheticals, which slightly reduces readability.

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?

Because there is no output schema, the description usefully explains the return shape and email status meanings. It omits some auth/parameter details covered by the schema and does not describe error behavior, but it is otherwise complete for this operation.

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 introduces a conflicting constraint: it says site_name is 1 to 60 characters while the schema allows maxLength 240. It also does not mention passport_token, though the schema documents it.

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 uses a specific verb ('Change') and clearly names the resource and the two settings affected: the daily digest email and the site name shown on the thank-you page. This is distinguishable from sibling tools despite not naming a direct alternative.

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 clearly indicates the context for use ('Change your form inbox's settings') and clarifies that either or both settings may be sent. It does not explicitly name alternatives or when not to use it, but the usage context is clear.

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