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

With no annotations, the description carries the full behavioral burden. It usefully discloses one important trait — the returned secret is shown only once and must be saved — but omits auth/permission requirements, whether the endpoint is verified, idempotency, URL validation rules, and limits like the maxItems constraints present in the schema.

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 with the action front-loaded and the retention warning right after it. No filler, and every clause carries information.

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 5-parameter creation tool with no annotations, no output schema, and zero schema description coverage, the description is too thin. It handles the return-secret aspect but leaves the agent without any guidance on the filter parameters (entity_ids, event_types, jurisdictions) that define what the subscription actually receives.

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?

Five parameters exist with 0% schema description coverage, yet the description explains none of them (name, url, entity_ids, event_types, jurisdictions). The phrase 'HTTPS endpoint' adds a marginal constraint beyond the schema's plain uri format, but everything else is undocumented in both places.

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 (subscribe) and resource (an HTTPS endpoint receiving registry changes), making the create action unambiguous against siblings like delete_subscription and list_subscriptions. It does not explicitly name a sibling, but the resource and verb are concrete enough to distinguish it.

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?

There is no explicit when-to-use or when-not-to-use guidance; the purpose implies usage but nothing tells the agent whether this is the right tool versus list_subscriptions or how it relates to existing subscriptions. The one operational hint is the directive to save the returned secret.

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