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

Annotations already declare write, open-world, non-idempotent, non-destructive behavior, so the bar is lower, and the description still adds real value: events are signed with Standard Webhooks and the signing secret is returned in this result. That one-shot secret disclosure is a behavioral trait an agent cannot get from annotations or schema. Remaining gaps (duplicate URL handling, whether the endpoint starts active) keep it from a 5.

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 tight sentences, front-loaded with the action and its effect, then the signing detail. No filler and nothing repeated verbatim from the schema or annotations.

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 usefully covers the most important return fact (the signing secret is in this result) and points to the sibling that re-exposes it. For a 3-required-parameter creation tool that is close to sufficient, missing only minor setup details such as project scoping and initial endpoint state.

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 only 33%, with project_id and event_types undocumented in the schema, so the description has to carry weight. It partially does by naming the event categories in prose (sends, deliveries, bounces, opens, clicks, replies, unsubscribes) and reinforcing the public-https requirement for url, but project_id gets no mention and the prose category names don't map cleanly onto the exact enum constants.

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 states a specific verb and effect ('Have Sendocado post events ... to a public https URL') plus the resource being created, and enumerates the event categories, so an agent can tell this is the webhook-endpoint creation tool. It does not explicitly contrast with update_webhook_endpoint, but the create semantics are unambiguous.

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?

Usage is implied rather than stated: the agent must infer that this is the tool for registering a new endpoint versus calling update_webhook_endpoint on an existing one. It does route the agent to a sibling for later secret retrieval (get_webhook_endpoint_secret), which is helpful, but there are no exclusions or preconditions spelled out.

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