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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds value by disclosing the result composition (default plus Agent-specific rubrics) and the default build-target behavior, which are not inferable from annotations alone.

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 tight sentences: the first states the core action and result contents, the second explains the default and the optional parameter. No filler or repetition of schema details.

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 list operation with two fully documented parameters and no output schema, the description covers the action, the returned composition, and the only subtle selection behavior (build default vs explicit build_id). Nothing needed for correct 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?

Schema coverage is 100%, so the schema already documents both UUID parameters. The description still adds meaning by explaining the conceptual role of build_id ('target the revision a specific Run ran against') and the default when it is omitted.

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 first sentence names a specific verb ('List') and resource ('evaluation rubrics a Run is scored against'), and clarifies the result composition ('platform default rubrics plus the Agent-specific rubrics for a build'). This distinguishes it from nearby eval/scores/queue-rubric tools and leaves no ambiguity about what is returned.

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 concrete usage guidance: omit build_id for the Agent's live build, or pass build_id to target the revision a specific Run ran against. It does not explicitly name sibling alternatives or exclusions, so it falls short of a 5, but the context is clear.

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