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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety behavior. The description adds context about the nature of the data ('canonical, versioned') and purpose ('approved for public discovery'), which is useful but does not disclose additional behavioral traits like ordering, pagination, or output format. With annotations handling safety, the description adds moderate value.

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 brief (two sentences) and front-loads the primary purpose. No unnecessary words. The 'No commercial obligation. Risk R0; PUBLIC.' segment adds some context but might be considered tangential; still, it does not bloat the description. Overall, it is appropriately concise.

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 absence of an output schema and the lack of parameter explanation, the description is incomplete. It does not explain what a 'capability contract' is, what the returned list looks like, or how to use the filters. Additionally, it fails to clarify its relationship with the sibling 'get_axiom_capability'. While the annotation set covers safety, an agent would struggle to invoke this tool correctly without additional external knowledge.

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 0%, so the description must explain the parameters, but it does not. The parameters 'kind' and 'riskClass' are enums, which provide some self-documentation, but the description gives no hint of their meaning or how they affect the result. An agent cannot infer whether 'kind' filters by service/platform or what riskClass ranges mean. This is a significant gap.

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 action: 'List the canonical, versioned capabilities approved for public discovery.' It identifies the resource (capabilities) and describes them as canonical and versioned. However, it does not differentiate itself from the sibling tool 'get_axiom_capability' (singular), which likely fetches a single capability. The additional note 'No commercial obligation. Risk R0; PUBLIC.' is somewhat ambiguous but does not detract from the core purpose.

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 provides no guidance on when to use this tool versus alternatives. It does not mention the sibling 'get_axiom_capability' for single-capability lookups, nor does it explain any prerequisites or exclusions. The only contextual hint is 'approved for public discovery,' which implies this is for public-facing capability listings, but no explicit when/when-not guidance is given.

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