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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds one genuine behavioral fact beyond the schema – that the call runs synchronously ($async=false) and maps to GET /accounts/{accountId}/contacts – but says nothing about default result size, paging behavior, or ordering when top/skip are omitted.

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 tight sentences, zero filler, and the core capability plus its mode split are front-loaded ahead of the lower-value endpoint reference. Every clause carries actionable information for the caller.

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 an 8-parameter, zero-required list tool with full schema coverage, no output schema, and a readOnly annotation, the description covers query modes, field-name sourcing, and sync execution. It could go one step further by hinting at the returned record shape or default page size, since no output schema exists to carry that.

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 the baseline is 3. The description rises above that by supplying concrete filter syntax with quoted field names and system codes ('Membership status' eq 'Active') and by pointing to wildapricot_list_contact_fields as the source of valid field names, which the per-parameter schema text does not explain.

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 states a specific verb and resource ('Search contacts and members') and immediately contrasts its two query modes, simple_query vs filter, which an agent can act on without opening the schema. It also names a sibling dependency (wildapricot_list_contact_fields) for valid field names, though it never distinguishes this list tool from get_contact or other read siblings directly.

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?

It gives clear selection logic between the two query parameters: simple_query for substring matching on name/org/email/phone, filter for OData expressions over known fields. What is missing is any exclusion guidance (e.g. when to prefer get_contact, or that unfiltered calls are paged/expensive), so it stops short of full when/when-not routing.

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