get_api_coverage

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

With no annotations, the description carries the burden, and it discloses the tool's return shape: three named sections (tools, resources, not_yet_supported). It does not explicitly state that the call itself is read-only or mention authentication prerequisites, though 'List' and the described output strongly imply a safe read operation.

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 compact, front-loaded with the main action, then usage rationale, then a bulleted return summary. Every sentence serves a purpose and no information is repeated.

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 zero-parameter discovery tool with an output schema present, the description supplies all decision-relevant context: what it lists, why to call it, and exactly what sections the response contains. 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?

The tool takes zero parameters, so there is nothing to explain; the empty input schema and 100% schema coverage are self-sufficient. Per the baseline rule for zero-parameter tools, a 4 is appropriate.

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: 'List all available Horizon MCP tools, resources, and unsupported operations.' It clearly defines the tool's scope and distinguishes it from the many sibling operating tools because it is the meta/capability-discovery endpoint.

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 explicitly states when to call it: 'before attempting a task' and when informing users about support. Since it is a unique discovery tool with no functional sibling overlap, the lack of a when-not clause is not a meaningful gap.

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