List Contacts

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is fully covered. The description adds a useful scope constraint ('for the authenticated user') but does not disclose behavioral details such as pagination iteration or whether all contact groups are included. No contradiction with annotations.

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?

A single seven-word sentence that front-loads the verb and resource and contains zero filler. Nothing is repeated from the schema or annotations, and every word earns its place.

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 read-only tool, the structured data covers a lot: the output schema explains return values, the schema covers parameters, and the annotations cover safety. The main gap is that with search_contacts, get_contact, and list_contact_groups as siblings, the description does not clarify exactly what subset of contacts is returned or when listing should be chosen over searching.

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 schema fully documents all four parameters (page_size, page_token, sort_order, user_google_email). The description's phrase 'authenticated user' slightly reinforces that user_google_email is the token holder's email, but this is marginal value beyond what the schema already states. Baseline 3 applies.

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 ('List') and a clear resource ('contacts'), scoped to 'the authenticated user.' This distinguishes it from mutating tools like manage_contact and single-item tools like get_contact, though it does not explicitly name or contrast any sibling such as search_contacts.

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 context is implied rather than stated: call this when you need the authenticated user's own contact list. However, there is no explicit guidance on when to prefer it over search_contacts (broader search) or get_contact (single contact), and no exclusions or alternative conditions are given.

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