Get inbound email

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description usefully discloses that authentication results (SPF/DKIM/DMARC) are included, which is behavioral value annotations cannot convey, but it says nothing about not-found/error behavior for an invalid id.

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 lists exactly what the caller receives; every clause earns its place and nothing is padded.

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?

With no output schema, the description does the necessary work of naming the returned fields, which is the key gap it needs to fill for a one-parameter read tool. Minor gap: no mention of behavior when the id is unknown or the email is unavailable.

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% and the single 'id' parameter is already documented as an inbound email ID with the 'inb_…' prefix. The description adds no further parameter meaning, so the baseline of 3 applies.

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 specific verb ('Get one') and resource ('received email') and enumerates what comes back: headers, content, attachments list, and SPF/DKIM/DMARC results. It is clear what it does, but it never differentiates itself from sibling get_email, so an agent cannot tell which of the two fetches inbound mail without inspecting schemas.

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 word 'received' implies this is the inbound counterpart to get_email, and the sibling list_inbound implies this is the single-item fetcher. However, no explicit when-to-use guidance or alternative (get_email vs. list_inbound) is named, leaving routing to inference.

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