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

Goes well beyond the annotations: it discloses the default per-call confirmation flow, that this can be toggled off for this tool, the audience reach ('everyone who follows your store'), and the required Cotlet API key access. This is the kind of external-effect and auth context annotations alone (readOnlyHint=false, openWorldHint=true) cannot convey.

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 first two sentences say essentially the same thing twice ('Weekly Note to Followers about new products or promotions, sent now or on a set date' vs 'Sends a Note to Followers about new products or promotions, now or on the date you set'). The genuinely useful behavioral info is buried after the repetition.

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 send-type tool with a simple two-param schema, no output schema, and clear annotations, the description covers audience, scheduling, confirmation, and auth adequately. Minor gaps remain around what the confirmation step entails and whether the send is queued or immediate.

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 body and send_on already carry their own descriptions. The description's mention of image-by-URL and now-or-later sending restates the schema rather than adding format or constraint detail, so it sits at the documented baseline.

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 (send) plus resource (Note to Followers) and scope (about new products or promotions, sent now or on a set date). An agent can tell it apart from the sibling product/store tools without opening the schema.

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?

Explains the trigger context (weekly note about new products or promotions, on demand or scheduled) and adds a confirmation rule ('Reaches other people: confirm with the user before each call'). No named alternative sibling is offered, but none directly overlaps in this toolset, so guidance is clear albeit without explicit exclusions.

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