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

readOnlyHint=true already covers the safety profile, so the bar is lower. The description adds genuinely useful context beyond annotations: newest-first ordering, cursor-paged results, and the underlying endpoint (GET /v1/contacts). It still says nothing about auth scopes, rate limits, or page-size defaults.

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 front-loaded sentence carrying resource, scope, ordering and pagination form, followed by a short API-reference line. Nothing is wasted.

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 simple read-only list tool with no output schema, the description covers scope, ordering and pagination mechanism, which is enough to call it correctly. Minor gaps are the absence of filter/alternative guidance, which is not strictly needed here.

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% and both parameters (limit, starting_after) are already documented in the schema. The description adds no parameter-level detail, 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?

States a specific verb and resource ('List contacts (CRM records)'), plus scope ('in the workspace') and ordering ('newest first'). The workspace scope implicitly separates it from bird_list_audience_contacts and bird_get_contact, but no sibling is named outright.

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 only implied: fetch all workspace contacts, advancing with a cursor. There is no explicit statement of when to prefer this over bird_list_audience_contacts or how to filter, so the agent must infer the routing.

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