List segment subscribers

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered structurally. The description adds the OAuth scope requirement ('segments:read'), which is genuine context beyond the annotations, but 'Reads account data' merely restates the readOnly hint and no return/pagination behavior is described.

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 purpose and with zero filler. It is efficient, though the middle sentence duplicates what readOnlyHint already conveys.

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 list tool with no output schema, the definition covers the safety profile via annotations and the auth scope via the description, but says nothing about what the returned subscriber objects contain or how expanded fields surface. Adequate for invocation, thin on outcome expectations.

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 page, limit, expand, account, segment_id and publication_id are all fully documented in the schema, including the expand enum meanings. The description adds nothing beyond that, which is the expected baseline when the schema does the heavy lifting.

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 segment subscribers'), which is enough to distinguish it from the many subscription-related siblings such as list_subscriptions or get_subscription. It does not explicitly name a sibling or clarify scope boundaries, but the segment-scoped target is unambiguous.

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?

Usage is implied by the name and the 'Reads account data' note, but there is no explicit when-to-use guidance, no exclusions, and no pointer to alternatives like list_subscriptions when the caller wants all subscribers rather than a segment slice. Adequate but with a clear gap.

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