Rohe Mail-Quelle

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description is consistent with a safe read operation. It adds the purpose but does not disclose the maxChars truncation behavior or the need for a valid uid. Since annotations cover the safety profile, the description adds modest value.

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?

A single, front-loaded sentence that states the main action and purpose without fluff. Efficient and readable, though it omits some necessary details.

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?

No output schema exists, so the description's mention of 'RFC822-Quelle' gives a good hint of the return value. However, it does not explain truncation via maxChars or how to obtain the uid (e.g., from mail_search). For a read-only tool with annotations covering safety, it is adequate but not fully complete.

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 50% with account and mailbox described, but uid and maxChars lack descriptions. The description does not compensate for these missing parameter semantics – it never explains how to identify the message (uid) or the effect of maxChars. An agent would have to infer these from the schema alone.

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?

States a specific verb and resource: 'Gibt die vollständige RFC822-Quelle einer Nachricht zurück' (returns the full RFC822 source). Mentions concrete use cases (header analysis, SPF/DKIM, forwarding). Does not explicitly differentiate from sibling mail_read, but the raw-vs-parsed distinction is implicitly clear.

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?

Provides a clear context for when to use it (analyzing headers, SPF/DKIM, forwarding) but does not explicitly compare to alternatives like mail_read or state when not to use it. No mention of the parsed-message alternative or exclusion criteria.

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