get_message

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

No annotations are provided, so the description carries the full burden. It discloses the return content ('headers and text body') and a preference ('prefers plain text'), which is useful behavioral context. However, it doesn't mention error handling (e.g., what happens if UID is invalid), performance aspects, or authentication requirements.

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 a single, efficient sentence that front-loads the core purpose and includes key behavioral details (return content and text preference). Every word earns its place with no redundancy or fluff.

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 read-only tool with no annotations and no output schema, the description provides adequate basics (purpose, return content). However, it lacks details on error cases, output structure beyond 'headers and text body', or how the 'prefers plain text' behavior works, leaving some gaps for an agent to use it effectively.

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 fully documents both parameters (folder and uid). The description doesn't add any parameter-specific details beyond what the schema provides, such as explaining UID format or folder naming conventions. Baseline 3 is appropriate when the schema does the heavy lifting.

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 states the specific action ('Fetch'), resource ('a single email'), and key identifier ('by UID'). It distinguishes from siblings like list_messages (which lists multiple) and search_messages (which searches by criteria rather than fetching by UID).

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 implies usage context by specifying 'by UID', suggesting this tool is for retrieving a known message rather than searching or listing. However, it doesn't explicitly state when to use alternatives like list_messages for browsing or search_messages for finding messages by content.

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