get_message

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

No annotations are provided, so the description takes the full burden. It discloses that omitting mailboxName searches all mailboxes and notes the performance cost, which is useful. It does not explicitly discuss error handling, output structure beyond high-level fields, or confirm the absence of side effects, but the read-only nature is strongly implied by the operation name.

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?

The description is only two sentences, front-loads the core operation, and spends one efficient sentence on the optional parameter. No redundant or filler content.

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 fairly simple read-only-style tool, the description is reasonably complete: it explains the primary call, the optional override, and the kind of result returned. It lacks details on error behavior or exact output structure, but it gives enough for an agent to invoke the tool correctly.

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 the schema already explains every parameter. The description adds slight extra context about mailboxName being slower when omitted, but most parameter meaning is already in the schema.

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 clearly identifies the operation as retrieving a single message by ID and names its major components (body, headers, recipients, attachments). This distinguishes it from tools like list_messages or search_messages, since the focus is on one message's full details.

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 gives clear context for when the optional mailboxName parameter is useful and why omitting it is slower. It does not explicitly name sibling tools as alternatives, but the usage guidance is contextually sufficient.

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