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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the required OAuth scope, the underlying endpoint (GET /contacts), and the exact return shape including paging fields (count, total, next_offset) with instructions on reusing next_offset as offset. That is precisely the added behavioral context annotations cannot convey.

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 tight paragraph where every clause carries load: purpose, fields, address inclusion trick, auth scope, endpoint, and return/paging contract. Front-loaded with the verb and resource.

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?

No output schema exists, yet the description fully describes the response envelope and paging, and it names the auth requirement. For a 6-parameter read-only list tool, nothing an agent needs in order to call it correctly is missing.

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%, so all six parameters are already documented. The description restates the 'with' behavior and the offset/next_offset paging link, which the schema also covers, so it adds little beyond structured fields. 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?

States a specific verb and resource ('List contacts'), clarifies the entity as 'customers and suppliers', and enumerates the fields returned. An agent can distinguish it from get_contact or create_contact, though it does not explicitly distinguish it from list_contact_people / list_contact_addresses.

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?

Provides concrete operational guidance: the 'contact' scope is required and 'with=main_address' is the way to pull address data inline. Usage is clear, but there are no explicit exclusions or 'use X instead' routing against the sibling list/get contact tools.

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