imap_preview_send_email

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

With no annotations, the description carries the full burden and does disclose the most critical behaviors: the tool does not send, it freezes a draft, and it returns a draftId requiring confirmation. However, the 'freeze' semantics are left vague — there is no disclosure of whether the frozen draft persists server-side, whether it can expire, whether repeated calls create orphaned drafts, or whether the operation is reversible.

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?

Two sentences totaling roughly 20 words, with the core purpose front-loaded in the first sentence and the follow-up action in the second. There is zero filler and every word contributes.

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 an 11-parameter tool with no annotations and no output schema, the description covers the purpose and the required next step but leaves gaps: the response shape beyond 'draftId', what happens to the frozen draft if never confirmed, and any caveats about confirmation being idempotent or time-limited. It is minimally viable but not fully self-sufficient.

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 of 3 applies — the schema already documents all 11 parameters. The description adds no parameter-level meaning beyond the schema (e.g., the BCC-defaults-merge behavior or the accountId/accountName interplay are only in the schema).

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-plus-resource construction ('Preview and freeze a new email without sending it') and immediately clarifies the non-sending scope, distinguishing it from any direct-send tool. It also names the companion tool (imap_confirm_send) and the 'new email' wording separates it from the reply/forward preview siblings.

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 clear context: this is the preview stage of a two-step send flow, and it explicitly instructs the agent to confirm the returned draftId with imap_confirm_send. 'Without sending it' and 'new email' provide partial exclusion guidance against send and reply/forward tools, though it does not explicitly enumerate when NOT to use it versus imap_save_draft.

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