List newsletter issues

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, but the description adds valuable context: it states this neither sends nor cancels an issue, requires an API key, returns subject/status/send time, and clarifies that an empty list is not an error. This goes well beyond the structured annotations.

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 tightly structured: main purpose first, then use cases, alternative tool, read-only note, auth requirement, return contents, and empty-list clarification. Every sentence contributes meaningful information without redundancy or fluff.

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 simple read-only list tool with one optional parameter, the description is complete: it covers what is returned, when to use it, the alternative tool, auth needs, and edge-case behavior. The absence of an output schema is compensated by the explicit mention of returned fields.

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?

The input schema fully documents the single 'limit' parameter with range, default, and ordering semantics, so schema coverage is 100%. The description does not add parameter-specific detail, but the schema already carries the full burden, earning the baseline score.

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 ('List') with a clear resource ('newsletter issues') and scope ('sent or scheduled, newest first'). It also distinguishes itself from the sibling tool list_newsletter_subscribers by explicitly stating it covers issues, not recipients.

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 gives concrete use cases: checking what went out and when, and confirming a scheduled send before queueing another. It also explicitly names the alternative tool for recipient-related queries, providing clear when-to-use guidance.

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