getContactsById

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

The description discloses that the operation is read-only and provides a rate limit (100 requests per 1m), which is valuable given no annotations are present. However, it does not mention error handling, authentication requirements, or behavior when the contact is not found. For a simple GET, this is partially transparent but not comprehensive.

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 very concise, with a single sentence that leads with the purpose. The rate limit and read-only status are included in parentheses, which keeps it compact. While the structure is a bit jumbled, it is efficient and free of extraneous content.

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 tool with one simple parameter and no output schema, the description should at least explain the parameter and likely return behavior. It does neither. The absence of usage guidance and parameter explanation leaves an agent with insufficient context to call the tool correctly, despite the clear naming convention.

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 schema has one required string parameter 'id' with 0% description coverage. The tool description does not explain what the id represents (e.g., the contact's unique identifier). The endpoint hints at it, but the description adds no semantic value beyond the schema, failing to compensate for the lack of schema documentation.

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 states a clear verb and resource ('Get a contact') and includes the endpoint with the {id} placeholder, which signals it retrieves a single contact by ID. This distinguishes it from the sibling getContacts tool, though it could be more explicit about the 'by ID' aspect.

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?

There is no explicit guidance on when to use this tool versus alternatives like getContacts. The name and endpoint imply it is for fetching a specific contact, but the description does not state this or mention any conditions (e.g., 'use when you have the contact ID'). No exclusions or alternative routing are provided.

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