Send email from an App ID

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

No annotations provided, so description carries full burden. It discloses billing behavior (SKU, hold/dispatch/settle, no charge on failure). Does not cover rate limits or auth requirements, but for a send email tool this is reasonably transparent.

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 sentences, front-loaded with purpose and plan requirement, followed by billing details. No redundant text, every phrase adds value.

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?

Given 6 parameters, no output schema, and no annotations, the description explains billing and plan but lacks details on optional body fields, construction guidance, or return behavior. Adequate but not complete.

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 only 17%. The description does not explain individual parameters (to, app_id, subject, etc.) beyond what the schema provides, missing an opportunity to add meaning. Only the billing context indirectly relates to app_id.

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 clearly states 'Send transactional/newsletter email' with a specific verb and resource, and 'through the platform email engine (Pro plan+)' distinguishes it from unrelated sibling tools.

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?

Explicitly mentions Pro plan+ requirement and billing implications, implying when to use. No direct alternatives given, but the tool is self-contained for email sending, so guidelines are adequate.

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