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

Adds substantial behavior beyond the annotations: restored messages are marked unread, the operation is safe to repeat and to run concurrently, the orphan fallback targets INBOX, and it declares the permission model ("Needs read and modify; every plan"). This exceeds the idempotent/destructive hints already provided.

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?

Dense and front-loaded: the core move happens first, then caveats. Every sentence carries weight, though the final permission clause is slightly clipped ('every plan') in a way that reads as shorthand rather than intent.

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?

An output schema exists so return values need not be described, and the description covers the mutation's permission model, idempotency, and orphan edge case. Remaining gap is the undocumented `dry_run`/`account` parameters for a tool that is safe to invoke without required args.

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?

With 50% schema coverage, the description compensates partially by explaining `orphans` (schema gives it no description) and the unread/restore semantics tied to `uid`. It says nothing about `dry_run` or `account`, leaving half the parameters undocumented in both places.

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: "Moves due messages from 'mailmcp-snoozed' back where they were, unread." The folder name and 'due' qualifier make it unmistakably distinct from its inverse sibling `snooze` without opening either schema.

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?

Gives one conditional gateway ("orphans=true ... only when the owner asks"), which is real when-to-use guidance, but never states the general trigger or explicitly contrasts with `snooze`. Usage is implied rather than spelled out.

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