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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description does add one genuine behavioral fact not in the annotations — results are truncated to the first 200 — which is useful, but it doesn't say whether truncation is detectable or how to get the rest.

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?

One short sentence, zero filler, with the resource and the 200-item limit front-loaded. Nothing could be removed without losing information.

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 one-parameter read tool with rich annotations, this is close but not complete: there's no output schema, and 'where each is in the sequence' is not explained (field names, possible position values, or ordering). An agent knows the call will succeed but not what it will get back.

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% with a single required campaign_id already documented as coming from list_campaigns. The description adds nothing about format or validation beyond that, 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?

The description names a specific resource (contacts within a campaign) and adds the returned dimension (sequence position), which cleanly distinguishes it from list_campaigns and get_campaign. It omits an explicit verb, but the name supplies it and the scope statement 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?

There is no guidance on when to call this versus get_campaign or list_campaigns, and no stated prerequisites. The only routing hint (campaign_id comes from list_campaigns) lives in the schema, not the description.

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