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

Annotations already indicate a non-read-only, non-destructive mutation. The description adds useful context about notes being saved as a structured entry with source tracking, which goes beyond the schema. However, it doesn't disclose potential side effects like duplicate contact handling or permission requirements.

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 two sentences long, front-loaded with the primary action, and contains no unnecessary words. Every sentence adds value, and the additional note about notes is relevant.

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 create operation with 7 fully-described parameters and no output schema, the description is adequate. It clarifies the scope (organization's address book) and a key side effect (structured notes). It doesn't explicitly state the return value, but that is a minor gap given the schema richness.

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 parameters are fully documented in the schema itself. The description adds no additional meaning beyond what the schema already provides, except for briefly noting the notes behavior which is also in the schema.

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 clearly states 'Create a new contact in the organization's address book' with a specific verb and resource. It distinguishes from sibling tools like create_contact_list, update_contact, and delete_contact by targeting the contact resource specifically.

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?

Usage is implied from the tool name and description, but no explicit guidance is given on when to use this versus alternatives like import_contacts or add_to_contact_list. The description does not provide exclusions or alternative recommendations.

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