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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds critical behavioral context: the tool's list grows over time, client tool lists are cached, and anything listed is reachable via query_capability_v1 even if the agent's current tool list predates it. This explains dynamic behavior and cache staleness, going beyond what annotations provide. No contradiction found.

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?

The description is two sentences long, front-loaded with the primary purpose, followed by essential usage caveats. Every sentence adds value; there is no wasted words or redundancy.

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 the tool has no parameters, has an output schema (covering return values), and annotations cover safety, the description provides sufficient context: purpose, when to use, and caveats about cache growth and capability availability. It is complete for an agent to decide when and how to invoke it.

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?

The tool takes zero parameters (schema coverage 100%), so there are no parameter semantics to explain. Per the rubric, 0 params warrants a baseline of 4. The description adds no parameter-related information, but none is needed given the empty 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 clearly states the tool's function: 'List available exascale.build data capabilities for agent discovery before querying.' It uses a specific verb (list) and resource (exascale.build data capabilities), and distinguishes itself from sibling tools by framing it as a discovery step before querying. It also references query_capability_v1, clarifying how it relates to the broader toolset.

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?

Explicit guidance is provided: call this 'before querying' and 'BEFORE stating that a capability is not available.' It explains when the tool is necessary due to client tool lists being cached and the capability surface growing. It also implies using query_capability_v1 as the follow-up for reaching listed capabilities, giving a clear workflow.

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