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

Goes well beyond the annotations by disclosing the auth requirement (API key required), the cost model (free to compete, no purchase), and error semantics (the only 409 is finalizing twice). This is real operational context that readOnlyHint/idempotentHint/destructiveHint do not convey. It stops short of 5 only because it doesn't describe the response shape.

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?

Three compact sentences, front-loaded with the action and precondition; the cost and 409 details are useful rather than filler. The parenthetical '(SPEC benchfree)' is slightly noisy but does not obscure meaning.

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 two-parameter mutation with no output schema, the description covers purpose, precondition, auth, cost, and the one expected error condition. It omits what finalize returns and that results are retrieved via benchmark_get_results, which is the only notable gap.

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 the schema itself documents run_id (pointing at benchmark_start_run) and the optional agent_id. The description adds nothing about either parameter, 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?

States a specific verb ('Finalize') plus resource ('in-progress benchmark run') and adds the outcome ('Scores the submitted answers'), which cleanly separates it from benchmark_start_run and benchmark_submit_answers in the sibling list. An agent can tell what this does without opening any schema.

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?

The phrase 'in-progress benchmark run' and 'scores the submitted answers' clearly imply the precondition (a run started via benchmark_start_run with answers already submitted). It gives clear context but names no explicit alternatives or when-not conditions, so it stops short of a 5.

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