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

With annotations already declaring destructiveHint=true, the description only needs to add context. 'Queue... for redelivery' usefully signals asynchronous, single-endpoint behavior and the underlying POST path, but it does not explain what the destructive aspect is (re-firing customer webhooks / altering delivery state) or whether the call is idempotent.

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 short sentences, front-loaded with the action and scope, followed by the use case and the exact REST route. Nothing is padded or repeated.

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 3-required-param mutation with no output schema, the description covers what the operation does, its scope, and that it queues work rather than completing synchronously. It stops short of describing the response or failure modes, which an agent calling a destructive write would benefit from knowing.

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% and all three parameters are documented there, so the baseline of 3 applies. The description adds no extra meaning about app_id/msg_id/endpoint_id beyond reiterating that redelivery targets one endpoint.

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: 'Queue one message for redelivery to one endpoint.' The word 'redelivery' implicitly separates it from svix_send_message (a fresh send), but it never names the closest sibling, svix_recover_endpoint, which also drives redelivery, so the distinction is left to inference.

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?

'The usual fix after a customer's endpoint was down' gives a concrete triggering scenario that an agent can match against a user's complaint about missing webhooks. It offers no when-not guidance and does not compare against svix_recover_endpoint or svix_send_message, so the routing decision is only half-supported.

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