payments_get_subscription_by_id

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds no additional behavioral context beyond the action itself—it does not mention return format, potential errors, or any operational nuances. With such strong annotations, some credit is given, but the description still contributes no extra transparency.

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?

The description is a single short phrase—extremely concise. While it is efficient and front-loaded, it provides no enriching context. It is not verbose, but it also lacks any explanatory structure that might help an agent. It is appropriately sized for a simple getter but somewhat minimal.

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 low-complexity get-by-ID tool, the description might be deemed sufficient, but it does not mention what is returned (since there is no output schema) or any side effects. The tool could return a subscription object, but without documentation, an agent is left to infer. Given the absence of an output schema, the description should at least hint at the return payload.

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 all three parameters (altId, altType, subscriptionId) are already documented with their descriptions. The description adds no additional meaning beyond what the schema provides, so the baseline score of 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 states 'Get Subscription by ID' which is a clear verb+resource pairing. It specifies the action (get) and the entity (subscription) with an identifier. However, it does not differentiate itself from sibling tools like payments_list_subscriptions or payments_get_order_by_id, though the name itself is reasonably specific.

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?

The description provides no guidance on when to use this tool versus alternatives. There is no mention of it being the single-subscription lookup versus listing subscriptions, nor any exclusions or caveats. An agent would have to infer from the name alone that this is for retrieving one subscription by ID.

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