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

With no annotations, the description carries the full burden, but it does disclose useful traits: sort order (newest first) and that extracted code is included in results. It omits whether listing marks emails as read, how deep 'recent' goes, and any pagination behavior.

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 that names the resource, ordering, and returned payload with no wasted words.

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 one-parameter list tool with no output schema, the description adequately covers what comes back. However, with no annotations and no output schema, it should clarify what 'recent' means and whether listing has side effects on read state.

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 description never mentions the limit parameter. The schema's default (10), min (1), and max (50) convey bounds structurally, but the description adds no meaning about how limit interacts with 'recent' results.

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?

Specific verb+resource (list emails) with an explicit description of returned fields (sender, subject, extracted code) and ordering (newest first). It does not explicitly differentiate itself from siblings like read_email or inbox_status, but the verb and scope are 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?

No guidance on when to use this versus read_email, inbox_status, or wait_for_email. It doesn't state whether it covers all folders, unread only, or how it relates to the sibling readers, leaving the agent to infer routing.

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