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

Annotations already flag destructiveHint=true, idempotentHint=true and readOnlyHint=false, and the description adds real context beyond them: the output is a draft held for operator approval, not an outbound send, and the 'Inbox approval' gate for the original draft is disclosed. The warning that can_retry/reachability signals do not establish delivery is a meaningful behavioral caveat. It does not contradict the annotations, though the destructive flag remains unexplained given the operation is described as draft-producing.

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 short paragraphs with the core action front-loaded and the risk caveats second, no filler. The fragments ('Unknown delivery cannot become a new send') and undefined terms ('eligible failed work', 'original resulting draft') cost some readability, but nothing is wasted.

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 annotations covering safety and idempotency, the description fills the important gaps: what artifact is produced (a draft), who must approve it, and which preconditions do not count as delivery proof. The remaining gap is routing guidance for the unknown-delivery / non-eligible cases.

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 three parameters already names its source (agents_list, engineering_follow_ups, inbox_list/conversations_search). The description adds no parameter-level meaning at all. Baseline 3 is appropriate when the schema carries the full burden.

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 action pair: recheck reachability, then turn eligible failed follow-up work into a draft for operator approval. The 'not a send' qualifier is a genuinely useful disambiguation from inbox_reply or a real send path. It stops short of naming the sibling it differs from (e.g. engineering_resolve_unknown), so it is clear but not sibling-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 conditions are implied rather than stated: 'eligible failed work' and 'unknown delivery cannot become a new send' tell the agent when this tool applies and when it does not. However, the agent is not told what to do instead for an unknown-delivery case, despite engineering_resolve_unknown and inbox_message_reconcile existing as siblings. No explicit prerequisites or alternatives are named.

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