discover_tools

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

The description contradicts the annotation readOnlyHint: true. The description claims the tool 'changes only the session's tool registry' which is a state-changing action, whereas readOnlyHint indicates a read-only operation. This conflict undermines trust.

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 somewhat verbose, repeating the category list and the idea of changing the registry. It could be tightened without loss of meaning, but it is not excessively long.

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?

The description covers the main functionality and how to invoke it. However, the contradiction with readOnlyHint creates confusion about side effects, and there is no mention of the response format. Overall it is mostly complete but not fully reliable.

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 schema description covers 100% of the parameter (category), and the description adds examples of valid values. While this is helpful, it does not significantly enhance the schema's explanation, so a baseline score of 3 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 clearly states the tool's purpose: to discover and activate additional tool categories. It lists the available categories and distinguishes between listing and activating, providing a clear verb-resource relationship.

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 explicitly states when to use the tool: 'Use this when a needed opt-in category is not currently exposed.' It also explains the two modes (omit category to list, provide category to activate), leaving no ambiguity.

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