edit_message

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

Goes well beyond annotations: recipients see an '(edited)' label, only text changes while attachments/quotes/reactions stay, only your own messages can be edited, the stored body is overwritten locally and the old text is not kept, and repeating the same edit has no further effect. These details are consistent with destructiveHint=true and idempotentHint=true rather than contradicting them.

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?

Front-loads the core action and the '(edited)' consequence, then routes to alternatives before parameter details. It is dense and information-rich, though a couple of clauses (e.g. the returns note) could be tightened.

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 mutation tool with no output schema, it discloses the return shape ({status, target_timestamp}), the server round-trip, and the local-overwrite behavior. Combined with annotations covering the safety profile, nothing an agent needs to call it correctly 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 already 100%, so the baseline is 3, but the description adds real meaning: target_timestamp provenance ('from the send_* result or the message id in get_conversation'), the 'no formatting conversion' constraint on message, and the E.164 / list_groups sourcing for recipient and group_id.

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 scope: 'Replace the text of a message you already sent (DM or group)'. It immediately distinguishes itself from send_message and delete_message, so an agent can pick it 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?

Explicitly names the situations to use it ('fix typos or update information') and the alternatives with their selection conditions: delete_message / delete_group_message to retract, and send a new message to reach different people. Nothing 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.