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

No annotations are provided, so description carries full burden. It discloses that capabilities listed may not have verified endpoints, indicating non-destructive, read-like behavior. Does not explicitly state 'read-only' but is sufficiently transparent about limitations.

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?

Relatively concise (3 sentences + note). Front-loaded with main purpose. Could potentially merge the note into the second sentence, but overall efficient and clear.

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?

No output schema and no description of return format, fields, or pagination. Given that this is a list operation, agents would benefit from knowing the structure of returned capability types. Lacks this detail despite low complexity.

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% with descriptions for both parameters. Description adds filter/search examples ('weather', 'translation') and ties to tool purpose, but does not provide significant new meaning beyond 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?

Description clearly states 'List available API capability types' with a specific verb and resource. It distinguishes from siblings (call_paid_api, discover_paid_api) by focusing on exploration rather than execution or endpoint validation.

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?

Explicitly tells when to use the tool (explore capabilities, filter by tag/search) and when not to (capability existence does not guarantee live endpoints, directing to discover_paid_api for that). Provides clear usage context and alternative.

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