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

Goes well beyond the destructiveHint=true annotation: it discloses the 60-minute window, the ownership requirement, that mentions are recalculated from mention tokens, that attachments are wholly replaced (and [] clears them), and that an 'edited' mark appears. This is rich behavioral context an agent needs before invoking a mutation.

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 dense sentences, front-loaded with the action and its hard constraint; every clause (timing, ownership, mentions, attachments, edited mark, late-correction routing) carries distinct information with no padding.

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 destructive mutation with annotations already flagging the safety profile, the description covers eligibility, timing, replacement semantics, and visible side effects. No output schema is needed for an edit confirmation, so nothing material is missing.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning: text fully replaces the prior text, mentions are recomputed, and attachments replace rather than append, with [] as the explicit clear-all value. That clarifies the replace-vs-append semantics the schema alone leaves ambiguous.

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 (Edits) and resource (the token owner's own regular message), and the qualifiers 'own' and 'regular' distinguish it from chat_send, chat_message_delete, and other chat siblings. An agent can identify the operation without opening the 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 concrete conditions for use: the message must be the token owner's own, and edits are only valid within 60 minutes of sending. It also implicitly routes late corrections to a reply. It does not name sibling tools as alternatives, but the when/when-not constraints are clear.

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