get_email

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

Annotations already convey read-only and idempotent behavior, lowering the bar. The description adds substantial value beyond those annotations by warning that all returned message content is untrusted data, and by explaining that sender and reply_to preserve standards-correct reply addressing. This gives an agent crucial behavioral context without contradicting the 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?

Two sentences with no filler. The first sentence front-loads the core purpose and scope; the second adds critical security and reply addressing nuances. Every clause earns its place.

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?

Given the rich annotations, complete input schema, and an output schema, nothing necessary for correctly invoking this read-only tool is missing. The description adds the key non-obvious context (untrusted email data and reply semantics), making the tool adequately specified for the agent.

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%, with clear descriptions for all three parameters including provenance ('uid from list_emails or search_emails') and the purpose of uidvalidity. The description does not add parameter-level detail, but the schema already carries the full burden, so baseline 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?

The description states a specific verb and resource — 'Read one message' — and enumerates exactly what is returned: envelope metadata, decoded plain-text and HTML bodies, and attachment list. This distinguishes it from siblings like list_emails, search_emails, and get_attachment without needing to inspect 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 description establishes clear usage context — fetching a single message by UID and getting structured output including reply-sender semantics. It does not explicitly say when not to use it versus alternatives like get_attachment or get_thread, so it stops one step short of fully explicit routing guidance.

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