Get message content

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

No annotations were provided, so the description carries the transparency burden. It states the tool 'Fetch' (implying a read operation) and describes the return content, but it does not disclose error behavior, permission requirements, or explicitly confirm that it has no side effects beyond the verb choice.

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, front-loaded sentence that directly states what the tool does without unnecessary words 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?

Even though the tool is simple, the description omits the mailbox parameter's semantics, provides no guidance on how to obtain a UID, and does not mention error cases. An agent would need to infer or guess several operational details, making the description incomplete for confident invocation.

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 0%. The description explains 'UID' as the identifier but does not mention the 'mailbox' parameter at all, leaving its purpose and default value undocumented. This is a clear semantic gap for one of two parameters.

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 uses a specific verb ('Fetch'), names the resource ('full parsed content (text/html body)'), and scopes it to a 'single message by UID.' This clearly distinguishes it from siblings like list_messages and search_messages.

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: you need a UID to fetch a message's content, which you would obtain from list_messages. However, it does not explicitly state when to prefer this tool over siblings or provide any exclusions or alternative mentions.

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