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

Annotations already declare non-destructive, non-idempotent behavior, and the description adds substantive context beyond them: the tool requires the email service to be connected first, issues send through the business's own mail service, postal_address is a legal requirement, and every issue carries one-click unsubscribe. That is meaningful operational disclosure.

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 explanation is informative but meandering, and the trailing 'Free. Free.' is a duplicated fragment that adds noise rather than front-loaded value. The key prerequisite (connect the service) is buried mid-sentence rather than first.

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 create tool with no output schema and thin annotations, it covers the artifact and prerequisites but omits what a successful call returns, whether name must be unique, or how the newsletter relates to the connected service afterward. Adequate but with gaps.

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?

With 100% schema coverage, the baseline is 3. The description reinforces the meaning of postal_address (shown at foot of every issue, legally required) but says nothing about name, description, or public_archive, leaving the schema to carry the rest.

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 explains what a newsletter is (a page at cncto.co/n/<name> people join to confirm their address) rather than crisply stating that this tool creates one, so the action must be inferred from the name/title. It distinguishes itself from the connect-service sibling by referencing newsletters_connect_service, but the verb+resource framing is weak.

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 gives one real prerequisite – connect the email service first via newsletters_connect_service – which is genuinely useful routing. It offers no guidance on when to use create vs. siblings like newsletters_update or newsletters_list, and no exclusions.

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