Find Customer by Email

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

Annotations already establish readOnly, openWorld, idempotent, and non-destructive behavior. The description adds valuable security context by stating 'Password hash is never returned,' which is not implied by the annotations or schema. It also confirms the operation returns an order count summary, aligning with the output schema without repeating it.

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?

Four short, dense sentences each contribute distinct value: purpose, return basis, sibling routing, and a security guarantee. There is no filler or redundancy, and the most important operational detail (exact match) is front-loaded.

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-value details are already covered. The description plus schema fully specify the input constraints, the alternative tool, the safety profile (via annotations), and the security guarantee. Nothing an agent needs to invoke or trust this tool is missing.

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 the parameter semantics are fully documented in the schema, including the exact-match requirement and rejection of partial strings. The tool description does not add additional parameter-level meaning beyond what the schema already provides, so the baseline of 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?

The description clearly states a specific action ('Exact email lookup') on a specific resource ('customer_entity') with a required precondition ('full valid email required'). It also explicitly names the sibling tool find_customers_by_name for partial name searches, providing immediate differentiation without needing to inspect schemas.

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 gives an explicit when-to-use condition (exact email match) and names the alternative for the not-this case ('For partial name search use find_customers_by_name'). This directly answers the routing question an agent would have between the two sibling lookup tools.

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