List sent emails

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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read. The description adds some behavioral context (confirming sent emails, filterability) but doesn't disclose anything beyond that, such as pagination behavior, default ordering, or whether unfiltered calls return all history. No contradiction with 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 two sentences, front-loaded with the action and resource. The first sentence states what it does and its filters; the second provides a practical use case. No redundant or filler content.

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 list tool with strong annotations, the description covers the main purpose and use case. However, since all parameters are optional, it would be more complete to explicitly state that unfiltered calls return the full email history. Still, the description is largely adequate for an agent to select and invoke correctly.

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% with descriptions for all four parameters (limit, offset, brand_id, client_id). The description adds that filtering by client or brand is possible, which is a slight semantic enhancement, but not enough to exceed the baseline of 3 when the schema already documents each parameter.

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 the action ('List') and the resource ('emails the platform has sent'), and adds filtering dimensions ('client or brand'). This distinguishes it from related sibling tools like get_email and resend_email, making the purpose 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?

It provides a concrete use case—'confirm whether an invoice reminder, verification, or notification actually went out'—which tells the agent when to use it. However, it doesn't explicitly mention alternatives to exclude, such as get_email for reading a single email, so it lacks explicit exclusions or alternatives.

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