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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds that results can be a summary list or full profile, but it omits matching behavior, pagination semantics, and output details beyond the mode names.

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?

The description is two short sentences with no filler. The search capability is front-loaded and the return-shape note follows immediately.

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 four-parameter search tool with no output schema, the description covers the core purpose and the two return modes but leaves important gaps around query matching semantics and pagination behavior. It is minimally adequate but not fully complete for reliable invocation.

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 75%, with the required query parameter having no schema description. The description partially compensates by saying search covers email, name, or phone, but it does not explain query syntax, matching rules, or how per/page interact beyond what the schema already says.

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 specifies the searchable fields: email, name, or phone. It also states the two possible return shapes, making the tool's purpose immediately clear without opening the schema.

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?

The description implies appropriate use as a contact lookup tool but gives no explicit guidance on when to use it versus alternatives such as nitro_query, nitro_import_contacts, or nitro_manage_audience. No exclusions, prerequisites, or alternative-routing advice are provided.

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