Read Saved Draft

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

Annotations already declare readOnly, idempotent and non-destructive, so the bar is lower, yet the description still adds real behavioral content: the required mailbox.read scope and the instruction to retain the revision and schedule version for subsequent mutations, which is optimistic-concurrency guidance not visible in the annotations. It does not explain what happens on a stale revision or how the 304 path behaves, so it is not exhaustive.

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 with no filler; the action and its scope come first, followed by the precondition and the follow-up obligation. Every clause contributes distinct information.

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?

With an output schema present, return values need not be described, and the annotations cover the safety profile; the description fills the remaining gaps of auth scope and version retention. The phrase "schedule version" is left unexplained, a minor gap for a tool whose whole point is version bookkeeping.

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 draftId, mailbox_id and If-None-Match are already documented with their targeting and conditional-request semantics. The description mentions revisions but does not add input-level detail (such as how the revision relates to If-None-Match), so the schema carries the load and the baseline 3 applies.

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?

"Read a saved draft and its current revision" states a specific verb and resource, and adds scope (current revision) that separates it from a plain listing call. It does not explicitly name sibling tools like mailbox_list_drafts or mailbox_update_draft, so differentiation is implied through the workflow rather than stated.

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?

"before editing or sending" gives clear context for when this read is the right call, positioning it upstream of update/send operations. It stops short of naming the alternative tools or stating when-not to use it (e.g., bulk inventory of drafts), which keeps it below a 5.

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