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

Annotations already cover the safety profile (readOnly, non-destructive, open-world), so the bar is lower. The description adds real value beyond them: the exact fields returned, the embeddable relationships, and the filter-expression grammar. It does not restate the read-only nature, so there is no contradiction.

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?

A single front-loaded block that states the resource, the returned fields, the filtering options, the relationships, and the endpoint with no filler. Every clause carries information an agent would otherwise have to infer.

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 correctly compensates by listing returned fields and relationships. For a 7-param list tool with full schema coverage, this is nearly complete; it omits only pagination behavior, which the schema handles via the next_page hint on page.

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 the schema fully documents page, with, limit, status, filters, ends_after, and ends_before. The description's example filters object and field list add marginal color but no syntax beyond what the schema already specifies; baseline 3 is appropriate.

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 opens with a specific verb+resource ('List subscriptions') and enumerates the fields returned, making the tool's job unambiguous. It contrasts implicitly with cratejoy_get_subscription via the list/get naming convention, but never names a sibling or states the single-vs-collection distinction explicitly.

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?

It describes how to filter ('Filter by status and end-date range, or with filters') but never says when to reach for this tool over get_subscription or the other list_* siblings, and offers no when-not conditions. Usage is only implied by the tool's purpose.

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