get_contact_by_id

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

The description explicitly labels the tool as 'Read-only', which is a direct behavioral disclosure. Since there are no annotations, this description fully carries the burden and is sufficient.

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, efficient sentence that front-loads the critical 'Read-only' attribute. Every word is necessary and there is no wasted text.

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?

Given the tool's simplicity (one parameter, no output schema, straightforward retrieval), the description provides all necessary information. No additional context is needed.

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 clear description of the single parameter. The tool description does not add additional meaning beyond the schema, so 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?

The description explicitly states 'retrieve one marketing contact by contact ID', using a specific verb and resource. It clearly distinguishes from sibling tools that retrieve multiple contacts (e.g., get_contacts_by_emails, list_contacts) or perform mutations.

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 indicates use when you have a specific contact ID. It does not explicitly mention alternatives or when-not-to-use, but the context is clear given the tool name and sibling tools.

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