Get customer

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered by structured data. The description adds useful context about the record's composition and the id convention, but does not mention auth requirements, error behavior, or whether the fetch fails hard on a bad id.

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 short sentences, front-loaded with the action and return contents, followed by the id convention. No filler and nothing repeated that the schema covers more precisely.

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?

A single-parameter read tool with full schema coverage, annotations carrying the safety profile, and an output schema that owns return-value documentation. Nothing an agent needs to invoke it correctly 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 coverage is 100% with a single parameter that already documents the pattern and example, so the description merely restates the cus_ convention. With the schema doing all the work, baseline 3 is correct; the description adds no syntax or edge-case detail beyond it.

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 (Fetch) and resource (one customer account) and clarifies the domain entity (a gym or yoga studio) plus what the record carries (plan, contact email, recent charges). There is no competing customer tool among the siblings, but the scope is unambiguous enough that an agent knows exactly what it gets.

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 by the tool name and the 'fetch one' framing, but there is no explicit when-to-use guidance, no statement of prerequisites, and no pointer to an alternative (e.g. how to find a customer id before calling). Adequate but with clear gaps.

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