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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint=false, so safety is covered. The description adds genuine behavioral detail beyond that: matching is substring-based, and 'expand' governs whether record answers are included. It still omits result-cap/pagination behavior and what happens when nothing matches.

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 tight sentences plus a bare endpoint reference, front-loaded with the search scope and with zero redundant phrasing. Every clause carries information the agent needs.

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 read-only search endpoint with fully documented parameters and annotations covering the safety profile, the description covers purpose, matching semantics, and the expand effect. Only minor gaps remain (result limits/pagination and empty-result behavior), which the schema's max parameter partly addresses.

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 schema already documents max, type, query, and expand with constraints. The description reinforces the substring nature of query and the effect of expand, but adds no syntax or format detail the schema lacks, making the baseline 3 appropriate.

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?

State a specific verb+resource ('Search the account's zones and records') with scope ('by name (substring match)') that separates it from ns1_get_zone/ns1_list_zones, which retrieve rather than search. It does not name any sibling explicitly, so an agent must infer the search-vs-get/list 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?

Usage is implied: reach for this when you want to locate zones or records by partial name instead of fetching them individually or listing everything. There is no explicit when/when-not statement and no mention of the sibling alternatives (ns1_list_zones, ns1_get_record), leaving the routing to inference.

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