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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context: the 'your' scope (only the caller's own issues) and the API key authentication requirement. It omits pagination behavior despite the limit parameter.

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?

Two short, front-loaded sentences with no filler; the purpose leads and the auth requirement follows. Slightly terse rather than padded, which is appropriate for a list tool.

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 read-only, single-optional-param list tool with no output schema, the description covers purpose, scope and auth. It leaves a gap around pagination/limit semantics and result shape, which matters given the tool returns a collection.

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 0%, and the single optional 'limit' parameter (default 10, max 50) is never mentioned in the description. The agent gets no information about page size or the existence of pagination beyond what the raw schema type hints at.

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 (Get) and resource (newsletter issues) and narrows scope with 'sent and scheduled', which separates it from siblings like list_newsletter_subscribers. It doesn't explicitly name an alternative, but the resource is unambiguous.

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?

The description says what you get but never says when to use this versus siblings such as list_newsletter_subscribers, nor whether there are prerequisites beyond the API key. No exclusions or alternative routing are offered.

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