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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds the useful scoping fact that it lists only sent mail from this account, but discloses nothing about pagination flow or result ordering that would help an agent drive the cursor.

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?

A single front-loaded sentence with no filler, and the scoping clause is placed after the core verb-resource pair. It is efficient, though arguably under-specified rather than genuinely tight.

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?

Output schema exists, so return values need not be explained, and annotations carry the safety profile. The remaining gap is that 'recent' and any default paging behavior are undefined, but the structured fields cover most of what an agent needs to invoke it.

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 100%, so both limit and cursor are already documented in the schema, and the description adds nothing about page size or cursor behavior. With 2 parameters and full schema coverage, the baseline of 3 is appropriate.

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 clear verb (List) and resource (emails) and adds scope ('sent from this account'), which distinguishes it from the sibling get_email at a high level. However, it offers no explicit differentiation from related siblings like get_email or the other list_* tools, and 'recent' is an undefined qualifier.

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?

There is no statement of when to use this tool versus alternatives such as get_email for a specific message. Usage is only loosely implied by 'recent emails sent from this account'; no exclusions, prerequisites, or routing guidance are provided.

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