nexus_get_categories

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

Annotations already declare readOnly, idempotent, and non-destructive behavior; the description adds useful behavioral context: the rate-limit distinction, the mutual-exclusion requirement, and the caveat that per-game lists may be sparse. No contradiction with annotations.

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 front-loaded with the core action and mode, and each sentence adds rate-limit, selection, or data-sparsity context. The return-shape line is slightly redundant given an output schema exists, but it is concise and does not hurt scannability.

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 two-parameter read-only tool, the description covers parameter selection, rate-limit behavior, data sparsity, and return shape. An agent has enough to invoke it correctly without consulting additional sources.

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% and each parameter has a helpful description and example. The description adds the crucial 'exactly one of domain_name or is_global' constraint, which is not enforced or expressed in the schema itself.

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 uses a specific verb and resource: 'Get mod categories (per-game or global) via v2 GraphQL.' It also clarifies the category scale and style, which separates it from related resources like single-category or tag-category tools.

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?

It gives clear usage context: provide exactly one of domain_name or is_global, and notes that the v2 GraphQL API does not consume the v1 REST quota. It does not explicitly name alternatives or when-not-to-use conditions, so it stops short of a 5.

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