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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely new context: the operation requires an existing lock and does not dispatch any message, which tells the agent the side effect is local-state only. It doesn't say whether the draft becomes unrecoverable, which keeps it from a 5.

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?

A single clause-pair sentence with zero filler; the action is front-loaded and the important non-effect ('sends no message') follows immediately.

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 and all three params documented in-schema, the description needs only the behavioral frame it provides. The 'existing lock' phrase implies a precondition (must hold the draft lock) that isn't spelled out as a failure mode, a minor remaining gap.

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 parameter names its source tool (agents_list, inbox_drafts, inbox_list/conversations_search), so the schema carries the semantics. The description adds nothing parameter-specific, which is the expected baseline here.

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?

States a specific verb and resource ('Rejects original draft') and pairs it with the key negative outcome ('sends no message'), which separates it from inbox_draft_approve and inbox_reply. It stops short of naming the sibling tools explicitly, so it lands at clear-but-not-maximally-differentiated.

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?

Usage is implied by 'original draft under its existing lock' — you reject a pending draft you already hold. There is no explicit when-to-use/when-not or named alternative, so the agent must infer the workflow from the sibling names.

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