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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds only the REST endpoint (GET /people/{id}), which confirms rather than extends the annotation, and it says nothing about authentication, error behavior, rate limits, or whether missing records return null or throw.

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 core action and then the API endpoint mapping. There is no filler or repetition, and both sentences earn their place.

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 simple one-parameter read with complete schema coverage and readOnly annotations, the description is minimally adequate. However, with no output schema present, it does not describe what the returned person object contains or what a not-found response looks like, leaving a small but real gap.

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%, and the single parameter already has a description ('The person id.'). The description's 'by id' and '/people/{id}' add no syntax, format, or constraint detail beyond what the schema provides, so the baseline 3 is 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 ('Get'), resource ('a single person (contact)'), and lookup key ('by id'), plus the exact REST endpoint. An agent can distinguish this from sibling getters like copper_get_company or copper_get_lead without opening any 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 'by id' phrasing implies the tool is for direct lookup when a person id is already known, but it gives no explicit when-to-use guidance, no exclusions, and does not name alternatives such as copper_search_people for finding a person by other attributes.

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