Get contact

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

Annotations already declare readOnlyHint=true, and the description redundantly states 'Read-only.' The description adds little beyond the annotation, though it clarifies the flexible identifier behavior (GUID vs externalId), which is a useful but minor behavioral nuance. No side effects or edge-case behaviors are described.

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, well-structured sentence that states the action, resource, and identifier options, followed by a clear safety qualifier. Every word contributes meaning, and there is no filler or redundancy.

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 get-by-ID tool, the description is complete. It identifies the resource, the required parameter, and the read-only nature. The return object is obvious for a 'get contact' operation, and the lack of an output schema does not create ambiguity. Sibling tools do not conflict with this focused operation.

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?

The input schema already provides 100% coverage with detailed descriptions for both parameters, including the idType enum. The description repeats the schema's distinction between GUID and externalId but does not add new semantic value beyond what the schema already communicates.

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 identifies the resource ('a single contact') with precise lookup keys (FastBound GUID id or externalId). This clearly distinguishes it from sibling tools like search_contacts or list_smartlists, which handle broader queries or lists.

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 clearly implies the use case: fetch one contact when you know its identifier. It does not explicitly name alternative tools or exclusions, but the singular focus and ID-based lookup make the intent obvious. Sibling context further clarifies when to use this versus bulk or search tools.

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