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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=false, so the description does not need to restate safety. It usefully adds two facts not in the annotations: the account-token auth requirement and 'Does not charge', which rules out an unintended billing side effect. It stops short of describing delivery/confirmation behavior, keeping it shy of a 5.

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 compact clauses, front-loaded with the auth precondition and the core action; nothing is padded or repeated. Every sentence earns its place.

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 two-parameter, non-destructive send tool with full schema coverage and no output schema, the description covers action, audience, auth precondition and the no-charge guarantee. Only minor gaps remain (no mention of submission limits or what the caller sees on completion).

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 description coverage is 100% for both parameters, so the schema already carries the meaning of 'site' (with an example address) and 'message' (character bounds). The description merely echoes the concept of a note tied to a site, adding no format or constraint detail beyond the schema. Baseline 3 applies.

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 names a specific verb and object ('Sends the DropTheHassle team a note about a site') and adds a qualifier about authorship ('in the account holder's words'). It is clearly distinguishable from the surrounding siblings (delete_site, deploy_site, list_sites), though it never explicitly names or contrasts an 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 states a precondition, '(needs account token)', which is real context for invocation, but gives no when-to-use vs alternatives guidance or exclusions. With no close sibling performing the same job, the implicit usage is reasonably inferable, so this lands at minimum-viable rather than poor.

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