create_contact

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

Annotations already indicate non-destructive and non-idempotent behavior. The description adds the nuance about optional fields but does not disclose side effects, duplicate handling, or auth requirements. With annotations covering the safety profile, this is adequate but not exceptional.

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 sentences, no fluff. The most critical information (required field, optional behavior) is front-loaded.

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 7-parameter tool with full schema descriptions and no output schema, the description highlights key usage patterns. It could mention return value or error cases, but the schema covers the other parameters. It's reasonably complete.

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 baseline is 3. The description adds value by reinforcing first_name as required and explaining the optional use of last_name, which goes beyond the schema's simple 'optional' label.

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 'Create a new contact' clearly states the action (create) and resource (contact). It distinguishes from siblings like update_contact and delete_contact by its verb and focus on creation.

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 explicitly states that first_name is required and last_name is optional, with a practical use case ('useful for contacts where you only know the first name'). However, it does not provide when-not-to-use or compare to other tools.

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