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

The read-only annotations already cover the safety profile, so the bar is lower. The description adds useful detail about what is returned (column names including custom fields), but does not discuss authentication, rate limits, or other operational context.

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 short sentences with no filler; the most important information (what the tool returns) is front-loaded. The endpoint path is slightly redundant but still compact and useful for mapping.

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 metadata tool with full parameter coverage and no output schema, the description adequately explains the return shape. It lacks usage context against siblings, but no critical information for invocation 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?

With one parameter and 100% schema description coverage, the schema already explains list_id as a digits-only contact list id. The description mentions the contact list context and shows the endpoint path, but adds no semantics beyond 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 states the resource and returned data ('column names of a contact list') and gives concrete examples plus the HTTP endpoint. It is clear enough to distinguish from siblings like list_contacts or get_list, though it uses a noun phrase rather than an explicit verb.

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?

There is no explicit guidance on when to use this tool versus alternatives such as benchmark_get_list or benchmark_list_contacts. The purpose is implied by the resource name, but no conditions, prerequisites, or exclusions are provided.

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