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

Annotations already declare this a safe read (readOnlyHint=true, destructiveHint=false). The description adds genuine value with the auth requirement ('requires read scope'), but it says nothing about pagination defaults or the ordering of returned contacts, which matters for a paginated list.

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?

Two short sentences, front-loaded with purpose and then the auth constraint; nothing is padded. It is arguably a touch too terse, but every sentence earns its place.

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 four fully documented parameters, safety annotations, and no output schema, the definition covers the essentials. It stops short of describing pagination behavior or result shape, which an agent would need to page through a campaign's contacts reliably.

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 id, page, page_size, and the status enum are already fully documented. The description only echoes the status filter and adds no semantics beyond the schema, which is the expected baseline here.

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 gives a specific verb and resource ('list contacts in a campaign') plus its scoping constraint (status filter). It is clear what the tool returns, but it never distinguishes itself from nearby siblings such as search_campaign_contacts or list_contacts, so an agent must infer the boundary.

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?

'with optional status filter' implies when the filter is worth using, but there is no explicit when-to-use guidance, no statement of when a search variant would be more appropriate, and no indication of behavior when the filter is omitted.

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