Get a customer

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

Annotations declare readOnlyHint and openWorldHint, so safety is already covered. The description goes further by disclosing return-behavior conditionals: bookings are included unless max_bookings is 0, ordered latest-start-first, and contact fields are suppressed unless include_contact_details is set. That is real behavioral context beyond the annotations.

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?

A single dense sentence that front-loads the core operation (one customer by ID) before the return-field details. No filler, though the packed clause structure is slightly taxing.

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 no output schema, the description carries the burden of describing the response and does so adequately by listing returned fields and the conditional gating of contact data. Minor gaps remain (pagination, error behavior for an unknown ID), but the essential calling information is present.

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 baseline is 3. The description adds outcome-level semantics not in the schema: it links max_bookings=0 to the absence of bookings in the response and specifies the sort order (latest start first), which is genuinely new information.

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 ('One customer by ID') and enumerates the returned fields, so an agent can immediately tell this is a single-record retrieval. It contrasts implicitly with the plural find_customers sibling but never names it, so sibling differentiation is not explicit.

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?

'by ID' implies the precondition (you must already have the customer_id), which is implied usage guidance. However, it never states when to use this versus find_customers, and gives no exclusions or alternatives.

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