mailkite_set_mailbox_message_flags

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

The description adds behavioral context beyond the annotations: it makes clear the operation replaces rather than merges flags, that the flags are IMAP-visible, and that a management session token is required. These are meaningful details not fully captured by the readOnlyHint/idempotentHint/destructiveHint annotations.

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?

Three short sentences, each earning its place: the core action, the IMAP-level behavior, and the required session token. Information is front-loaded and there is no filler.

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 flag-setting tool, the description covers the core action, the replace behavior, and authentication. A small gap is that the 'address' parameter is left semantically vague — the schema only labels it as a query parameter — so an agent may need additional inference about whether it refers to a mailbox address or another entity.

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 baseline is 3. The description itself does not meaningfully elaborate on the parameters beyond what the schema already says, though it does reinforce the replace semantics of the flags parameter.

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 ('Replace') and a precise resource ('a message's IMAP flags'), with an example ('mark it Seen') that makes the operation unambiguous. It also clarifies the flags are the same as those seen by an IMAP client, which distinguishes this from other flag-adjacent or mailbox operations.

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 intended use is implied by the name and description, and the auth prerequisite ('Requires a management session token') is helpful. However, the description does not explicitly state when to use this tool over alternatives or when not to use it, leaving sibling differentiation mostly to the tool name.

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