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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description's one addition is the shape of the result (tags, subscription status), which is useful since no output schema exists, but it says nothing about empty-result behavior, ordering, or the API key override.

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, zero filler, with the search scope front-loaded before the return-value clause. 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?

Adequate for a four-parameter, non-destructive search with a fully documented schema and annotations covering safety. The only shortfall is the absence of any note on result behavior (paging is in the schema but result ordering and no-match handling are unstated).

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 query, page, pageSize and apiKey are all documented in the schema itself, including that query matches email/first name/last name. The description restates the matching fields but adds no format, syntax, or paging semantics beyond what the schema already provides, so 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 ('Search contacts') plus the matching fields (email address or name) and the return payload (tags and subscription status). It implicitly separates itself from list_contacts by framing this as a query-driven lookup, though it never names the sibling explicitly.

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: reach for this when you have an email or name and want matching contacts. There is no explicit when-to-use/when-not guidance, no statement of whether this replaces or complements list_contacts, and no mention of the required query parameter or authentication expectations.

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