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

Annotations already declare readOnlyHint and destructiveHint=false, but the description adds genuinely non-structured information: the required 'contact' scope and the underlying endpoint path. It also discloses the paging contract (next_offset → offset), which goes beyond a bare 'list' statement.

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?

Four short sentences, front-loaded with the purpose, then scope, then endpoint, then return shape. Nothing is redundant and every sentence carries actionable information.

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?

With no output schema, the description helpfully names the return envelope fields (count, total, next_offset, items) and the paging mechanics, and it states the auth scope. Only marginal gaps remain, such as what the items contain.

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% and all six parameters are documented in the schema, including q, sort, with, limit, filter and offset with examples. The description only echoes the offset/next_offset relationship already stated in the schema, so it adds little beyond baseline.

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 the contact groups') plus the concrete endpoint GET /contacts/configuration/groups, which makes it distinguishable from sibling lists like smallinvoice_list_contacts or list_contact_people. It does not explicitly name those siblings, but the resource is unambiguous.

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?

Adds useful call context — the required 'contact' scope — and implies a paging loop by explaining how to pass next_offset back as offset. It gives no guidance on when this tool should be preferred over related list tools or when not to use it.

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