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

Annotations already establish the safe-read profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the bar is lower. The description adds real value beyond that by disclosing the return shape: all fields with Field1...Field24 holding custom columns, which tells the agent how to interpret results rather than just that the call is safe.

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 the resource and scope front-loaded, no filler. The raw GET path is somewhat redundant with the tool name but cheaply conveys the list/contact hierarchy.

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?

There is no output schema, and the description compensates by explaining what comes back (all fields, with Field1...Field24 as the custom columns). For a simple two-parameter read, that is nearly complete; only auth or error behavior is unaddressed.

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 both list_id and contact_id are fully documented in the schema as digit-only IDs. The description adds no new parameter semantics beyond the endpoint path, so the 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 names a specific verb+resource: fetch a single contact from a list, and the singular 'One contact' distinguishes it from the plural list/search siblings. However, it never names those alternatives (benchmark_list_contacts, benchmark_search_contacts) explicitly, so the differentiation is implicit rather than stated.

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 only implied by 'One contact of a list' plus the required list_id/contact_id pair, which suggests direct ID lookup. There is no statement of when to use this versus benchmark_list_contacts or benchmark_search_contacts when the ID is unknown.

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