get_email

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

Goes well beyond the annotations: it discloses that the message is not marked read, that HTML is converted to text, that no remote images are fetched, and that mail content is untrusted data. These are non-obvious side-effect and safety facts an agent cannot infer from readOnlyHint/idempotentHint alone.

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?

Four short sentences, each earning its place: purpose and key first, then side-effect, then rendering behavior, then the trust warning. Zero filler.

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 correctly summarizes the return payload (decoded text plus attachment metadata) and the safety profile. The only gap is the undocumented max_chars truncation parameter, which an agent may need to tune for large messages.

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 25% (only uid_validity is documented in-schema), so the description carries some burden. It names mailbox, UID and UIDVALIDITY and their role, but says nothing about max_chars or its truncation behavior, leaving one parameter undocumented in both places.

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 (read) plus the exact resource (decoded plain text and attachment metadata) and the lookup key (mailbox, UID, UIDVALIDITY), which cleanly separates it from siblings like search_emails, list_attachments and download_attachment.

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?

'from search_emails' tells the agent where the required UID/UIDVALIDITY pair must come from, establishing the correct call order. It gives clear context but no explicit exclusion (e.g., when to prefer download_attachment or list_attachments instead).

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