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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds the useful notion that results are 'reusable' and can be passed along as references, but says nothing about matching semantics, result limits, or behavior on zero 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?

One front-loaded sentence with no filler. The phrase 'attaching a returned reference' is slightly jargon-y but earns its place by describing the downstream use of results.

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?

With an output schema present, return values need no explanation, and parameters are fully documented in the schema. What remains thin is behavioral fidelity around matching and scoping, so it is not fully complete but is adequate for a simple search tool.

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 both parameters (query, limit) are fully documented in the schema. The description adds no additional syntax, matching rules, or defaulting guidance beyond that, 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?

States a specific verb and resource ('search reusable contacts') in plain terms. However, it doesn't clarify the 'household' scope implied by the title, nor how it differs from contact-related siblings beyond an implicit reference to creating one.

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?

Gives a concrete triggering condition: search before creating a contact, or before attaching a returned reference. It stops short of naming the alternative (create_contact) explicitly or stating when not to use it, but the intended call moment is clear.

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