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

Annotations only declare destructiveHint=true and readOnlyHint=false, but the description adds substantial behavioral context: partial-update semantics ('Only supplied fields change'), wholesale replacement of sample_params and schema_gen_params, the replace-not-clear constraint on the judge, scenario_type immutability, authorization requirements, and the side effect that changed definitions make previous results stale. This goes well beyond what annotations 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?

Five dense sentences, no filler. The purpose is front-loaded, and every subsequent sentence adds a distinct piece of operational knowledge: prerequisites, partial-update semantics, replacement behavior, immutability constraints, and staleness consequences. The docs pointer is a single efficient clause.

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?

Given 13 parameters, an output schema (so return values need not be described), and annotations covering the safety profile, the description covers the critical behavioral gotchas — replacement semantics, immutability, side effects, and authorization. It does not enumerate every parameter's interaction, but the schema's 62% coverage plus the description's focus on the riskiest behaviors makes this adequately complete.

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 schema description coverage at 62%, the schema does not carry the full burden, and the description compensates by explaining the replacement behavior of sample_params/schema_gen_params and the replace-not-clear constraint on the scoring judge. It adds meaning the raw schema (which only labels them 'replacement' objects) does not fully convey, though some param-level richness is already present in 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 opens with a specific verb and resource: 'Edit a benchmark's test definition or scoring configuration.' This clearly distinguishes it from siblings like create_benchmark_scenario, get_benchmark_scenario, run_benchmark, and delete_benchmark_scenario, since it names exactly what aspect of the benchmark is being mutated.

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 description gives clear context: the prerequisite ('Requires owner and a plan with benchmarks'), an explicit when-not ('no model run', distinguishing it from run_benchmark), and follow-up guidance ('Re-run affected models to refresh their scores'). It stops short of naming sibling alternatives by name, which is the only reason it doesn't earn a 5.

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