Pay: subscriptions by user

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so 'Read-only' is largely confirmatory; however the description adds real behavioral value by enumerating the returned fields (id, name, status, price, created date), which is not in the annotations or schema. It omits pagination/result-size limits, so not a full 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?

Three short sentences, front-loaded with the core action and scoped to user id early. Minor redundancy between 'List subscriptions accessible to a user' and 'Lists the subscriptions one project user is linked to', but nothing wasted.

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 discloses the returned fields, and the disambiguation against sibling read tools is complete. It stops short of noting ordering, limits, or behavior when the user has no subscriptions.

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 100% and the single parameter is fully documented including how to obtain it (users_list). The description only restates 'by numeric user id', adding no new syntax or constraint beyond the schema, so the baseline 3 applies.

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 ('List subscriptions accessible to a user') and immediately narrows scope to one project user by numeric id. It also names the sibling tools it is not, so an agent can distinguish it from pay_entitlement and pay_subscriptions_check_access without opening schemas.

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 an explicit use case ('look up a customer's subscriptions') and an explicit exclusion rule: pay_entitlement and pay_subscriptions_check_access only report on the signed-in user. This is exactly the when-to-use / when-not-to-use contrast the dimension asks for.

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