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

Annotations already declare destructiveHint=true, and the description layers on context the annotations cannot convey: the deletion is for everyone in the conversation, irreversible ("cannot be undone"), time-boxed to 60 minutes, and rate-limited to 100/day. This is exactly the extra behavioral burden a destructive tool needs covered.

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?

Four tight sentences, front-loaded with the id I/O contract and then the destructive/temporal/quota constraints. No filler and no repetition of the title.

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 a two-parameter destructive mutation with annotations present, the description covers scope, irreversibility, time window, and quota — the constraints an agent must respect before calling. No output schema exists and "Ids out: none" correctly signals no id is returned.

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 both messageId and connectionId are already documented; baseline is 3. The description's id-lineage note (from list_chat_messages → messages[].id) and "Ids out: none" add only mild value over the schema's own "from list_chat_messages" text.

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 with exact scope: "Delete ONE message you sent ... for everyone in the conversation." The "you sent" and "for everyone" qualifiers let an agent separate it from delete_chat and edit_message without opening schemas.

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 strong usage conditions — only within 60 minutes of sending, only messages you sent, consumes a daily allowance of 100. It does not name the sibling to use instead when the 60-minute window has passed (e.g. edit_message or delete_chat), so a route-out is left to inference.

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