delete_message

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

Annotations already declare destructive=true and idempotent=true, but the description goes well beyond them: irreversible, older clients may silently ignore it, repeating has no further effect, and the local store copy is retained. These are non-obvious behavioral traits an agent needs before invoking.

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-loaded with the core action, then alternatives, then constraints, then return value. Dense but each clause carries information; the constraint list is slightly packed but nothing is redundant.

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 no output schema, the description still reports the return shape ({status: 'deleted'}), covers irreversibility, idempotency, client-version caveats, and where to obtain the timestamp. Nothing needed 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 100%, so the baseline is 3, but the description adds real value: recipient is specified as an E.164 number and target_timestamp as a millisecond timestamp obtainable from the send_message result or get_conversation. That clarifies format and provenance beyond the schema's generic wording.

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 precise verb and resource ('Remote-delete (unsend) a message you sent to one contact') with explicit scope ('one contact'). It names the two sibling tools it is distinct from, so an agent can route correctly without opening any 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 explicit routing rules: use delete_group_message for groups and delete_local_messages for local-only removal. It also states the precondition that only your own messages can be deleted, which is exactly the when/when-not guidance needed.

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