List subscribers

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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds real behavioral context on top: eventual consistency ('someone added a minute ago may not show yet' via background table fill), short/empty filtered pages that still have a next_cursor, and the 'paid includes founding members' semantics.

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?

Front-loaded with the return payload and ordering, then pagination caveats — every sentence carries information. The opening sentence is a fragment and the density of caveats makes it slightly harder to scan, keeping it from a 5.

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 compensates well by naming the returned fields and ordering, and it fully covers pagination and staleness. It doesn't say how end-of-list is signalled (e.g. missing next_cursor) or whether a total count is returned, a minor remaining 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?

Schema coverage is 100%, so baseline is 3; the description goes further by clarifying that 'paid includes founding members' and by explaining cursor/filter interaction, which the schema alone does not convey. The 'since' date format and limit bounds are left to the schema, which is acceptable.

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?

A specific verb and resource ('Lists subscribers ... from the subscriber dashboard') plus the returned fields (plan, start date, activity rating) and ordering (newest first). It does not explicitly differentiate itself from siblings like export_subscribers or list_subscriber_tags, so it stops short of a 5.

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?

Strong operational guidance: it explains cursor round-tripping, page size, and that 'the plan and since filters apply inside each page'. It never says when to prefer export_subscribers or list_subscriber_tags over this tool, so the alternative-selection guidance is absent.

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