Delete Message

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

Goes well beyond the destructiveHint annotation by describing validation of ids, posting limit checks, attempt recording, legacy endpoint usage, and honest failure when decommissioned. This adds rich behavioral context not captured in annotations.

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 sentences, front-loaded with the primary purpose and then behavioral details. Every word earns its place with no redundant content.

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?

Given the destructive nature, annotations, and output schema, the description sufficiently covers side effects, failure modes, validation, and identity handling. The existence of an output schema means return values need not be explained in the description.

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 baseline is 3. The description adds context about active/specified identity and validation, but does not substantially enhance parameter meaning beyond what the schema already provides.

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?

The description clearly states 'Delete (unsend) a Messenger message' with a specific verb and resource. It distinguishes from sibling tools like delete_post by specifying 'Messenger message' and using the term 'unsend'.

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?

Provides clear context that the tool deletes as the active or specified identity and mentions the legacy Mercury endpoint. While it does not explicitly list alternatives or when-not-to-use, the 'unsend' terminology and resource scoping make the intended use clear.

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