get_message

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

No annotations are provided, so the description carries the burden. It discloses that include_body defaults to True and max_body_chars truncates the body, which is useful behavioral detail. However, it doesn't mention what happens if the UID is not found, or any other side effects or error 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?

The description is concise and well-structured: a single clear purpose sentence followed by a bullet-like arg list. Every sentence earns its place, no filler or repetition.

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 might need to cover return format, but it's a simple get operation. The parameters are fully documented, usage context is clear, and behavioral details like truncation are provided. Minor gap: no mention of error/not-found behavior, but overall it's adequate for a straightforward tool.

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 0%, but the description fully compensates by explaining each parameter: list_name is the mailbox/list name, uid is from search/page results, include_body controls body inclusion, max_body_chars truncates the body. This adds meaningful semantics beyond the bare 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 begins with a specific verb+resource: "Fetch a single message by UID". It clearly distinguishes this from sibling tools (search_list, page_list) by stating it retrieves one message based on a UID from a prior search/page result.

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 states the UID must come from a prior search/page result, which implies the tool should be used after those. It gives clear context for when to use the tool, though it doesn't explicitly mention when not to use it or list alternatives.

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