List what you subscribe to

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

Annotations already cover readOnly, openWorld, idempotent, and non-destructive behavior. The description adds that both free and paid subscriptions are included and that results are scoped to the account, which is useful. It does not disclose pagination, ordering, or empty-result behavior, but the annotation coverage lowers the burden.

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 two concise sentences with no fluff. The main action is front-loaded, and the second sentence earns its place by explaining when the tool is useful.

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?

This is a low-complexity read-only listing tool with one optional parameter and strong schema coverage. The description plus schema is sufficient for an agent to select and invoke it. A brief note on return shape would be a minor improvement, but it is not a material gap.

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?

The only parameter, publication, is fully documented in the input schema with matching semantics and default behavior. The description itself adds no extra parameter detail, so with 100% schema coverage the baseline 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 clearly states the action (List) and the resource (publications this account subscribes to), adding the free/paid scope. It is distinct from sibling tools like list_subscribers, which involve people subscribed to the user rather than publications the user follows.

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 second sentence gives clear practical context: use this before searching for more content so you know what is already in your inbox. It does not explicitly name alternatives or state when not to use it, but the intended use case is evident.

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