imap_copy_message

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

Annotations are absent, so the description carries the full behavioral burden, and it is only a single clause. It does not state whether the source message remains intact (the key difference from imap_move_message), whether the destination mailbox must already exist, whether duplicates are allowed, or what error states exist. The cross-account capability appears in the schema description, not the tool description; the tool description itself discloses almost no behavior beyond the verb 'copy'.

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?

At six words, the description is maximally front-loaded and has no filler; every word earns a place. The brevity reads as telegraphic rather than distilled ('to mailbox' lacks an article), but there is no redundancy or burying of the key action.

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 moderately complex operation that supports cross-account copies and has no annotations, the one-sentence description is too thin. An agent still has to guess what happens when the destination exists, whether the source is preserved, and how conflicts are handled; although the output schema covers return shape, the behavioral envelope is largely missing beyond the schema's parameter notes.

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%, and each of the 4 parameters (account_id, message_id, destination_mailbox, destination_account_id) has a type, description, and default/nullability. The tool description adds nothing about parameters, but with the schema carrying full weight, the baseline of 3 applies. Cross-account semantics are effectively explained in the schema description.

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 the specific verb (copy) plus resource (message) and destination (mailbox), so the core purpose is unambiguous. It distinguishes from siblings mainly through the semantics of 'copy' as opposed to imap_move_message or imap_delete_message, but the differentiation is implicit rather than explicit.

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 over alternatives like imap_move_message, imap_append_message, or ews tools, and no exclusions or prerequisites. The schema description mentions 'same-account or cross-account copies,' which is scope context but not routing guidance. An agent must infer when copy rather than move or append is appropriate.

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