List interface categories

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so repeating 'read-only, idempotent' adds little. The description does contribute real context beyond them: it is parameterless, safe to call once (cacheable), counts reflect only approved entries and are live, and it never returns entries themselves — a scope boundary the annotations do not express.

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?

Front-loads the return content, then the guidance, then the exclusions. Three dense sentences with no filler; every clause either describes content, routes to an alternative, or sets a scope boundary.

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, read-only enumeration tool, the description covers what it returns, why to call it, and when to use something else. An output schema exists, so return formatting need not be explained; nothing an agent needs in order to call it correctly 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?

Zero input parameters, so the baseline is 4. The description still adds meaning by tying the returned category values to the consuming tools' 'category' argument, clarifying the output-to-input contract even though no schema parameter exists to document.

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?

States a specific verb and resource ('Return the fixed taxonomy of Agent Nexus') and enumerates the exact contents ('api', 'mcp', 'cli' with label, one-line definition, live approved count). An agent can distinguish it from list_entries, search_registry and discover_capabilities without opening any schema.

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?

Gives explicit when-to-use ('call it once to learn the exact values accepted by the category argument', 'size the catalogue before paging') and explicit when-not, routing to three named siblings: list_entries to enumerate a layer, search_registry for a keyword, discover_capabilities for a plain-language need.

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