imap_append_message

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

There are no annotations, so the description carries the full burden of behavioral disclosure. It only restates the basic action and does not mention side effects, authentication/account requirements, whether the mailbox must exist, message flags, or error conditions. The 'raw RFC822' wording hints at no transformation, but that is minimal.

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 with no filler or redundant phrasing. Every word contributes to the core operation, making it easy to parse quickly.

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 simple append operation with fully documented parameters and an output schema available, the description is minimally viable. However, it omits operational context such as precondition of mailbox existence, account selection behavior, and whether the append modifies or preserves the raw message, so an agent may still make incorrect assumptions.

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 parameters are already documented with clear meaning (mailbox name, raw RFC822 content as UTF-8, account identifier with default). The description adds no parameter semantics beyond what the schema provides, so the baseline score of 3 is appropriate.

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 states a clear verb-resource pair: append a raw message to a mailbox. It is distinct from sibling operations like imap_move_message, imap_copy_message, and the send_message tools, since 'append' uniquely means inserting a message into an IMAP mailbox.

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 no guidance on when to use this tool versus alternatives such as smtp_send_message or graph_send_message, nor does it mention whether the mailbox must already exist via imap_create_mailbox. The only implied usage is the action itself, with no explicit context or exclusions.

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