Get contact

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

The annotations already declare readOnlyHint=true and openWorldHint=true, and the description's 'Read-only' merely echoes the readOnly annotation without contradicting it. It adds no new behavioral detail such as error conditions, authentication needs, or return format, but the safety profile is already covered by 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?

The description is a single front-loaded sentence that states the resource, identifier options, and read-only nature with zero filler. Every word contributes meaning.

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 read-only lookup tool, the description plus fully documented schema and safety annotations are largely sufficient. The only notable missing element is explicit guidance on when this tool should be chosen over search_contacts, and there is no output schema that would need return-value explanations.

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 schema fully documents all three parameters. The description only restates the idType distinction already present in the schema and adds no examples, default clarifications, or format details 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?

The description uses a specific verb ('Retrieve') and names both the resource ('a single contact') and the two lookup keys ('FastBound GUID id or your externalId'). This clearly distinguishes it from search_contacts, which returns multiple contacts, and update_contact, which modifies.

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?

It implies the tool is for retrieving exactly one contact when you already have an identifier, but it never explicitly says when to use it instead of search_contacts or lists alternatives. The 'Read-only' tag gives safety context, but there is no direct routing guidance.

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