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

With no annotations, the description carries the full burden and does add useful behavior: payload shape (JSON with a "text" summary), the x-plinth-signature HMAC header, and which destination URLs are accepted. It does not disclose that this registers a persistent subscription, whether re-adding the same URL duplicates or replaces, or what happens on delivery failure, which are significant gaps for an unannotated write tool.

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?

Dense and front-loaded: the action comes first, then the event vocabulary, then the payload/header contract. The event list is long but each entry is load-bearing since no enum exists in the schema.

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 three-parameter tool with no output schema and no annotations, the description covers destination support, event selection, payload format, and signing. It omits return behavior (does it return an ID?) and lifecycle details like duplicates or removal, which leaves minor gaps.

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 67% and there are no enums, so the description does real work: it supplies the entire valid value set for events and the "empty means all" default, neither of which appears in the schema. It adds little for url and authorization, which the schema already documents.

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 concrete verb and resource ("Send Plinth events to a URL") and enumerates the exact event types it covers, which clearly separates it from webhooks.list and webhooks.remove. It does not explicitly distinguish itself from the sibling webhooks.test, which also sends events, so it falls short of full sibling differentiation.

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 practical usage context: which destinations work out-of-the-box (Slack, Discord, Telegram, Zapier) and that an empty events list means "all". It never states when to prefer this over webhooks.test or how it relates to webhooks.remove, so no exclusions or alternatives are provided.

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