List Custom Rules

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

The annotations already declare `readOnlyHint: true`, `idempotentHint: true`, and `destructiveHint: false`, so the safety profile is covered. The description adds only a mild behavioral nuance with 'currently stored', implying a live snapshot, but it does not disclose response format, pagination behavior, or ordering semantics.

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 a single, front-loaded sentence with no redundant wording. Every word serves to identify the operation, scope, and object, making it highly efficient for an agent to parse.

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 simple read-only listing tool, the description, schema, and annotations together are mostly sufficient: annotations cover safety, the schema covers the required and optional parameters, and the description states the object being listed. The main omission is the output shape and pagination behavior, especially since there is no output schema, but the risk of mis-invocation is low.

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?

Input schema description coverage is 0%, so the description should compensate for parameter meaning. It does relate the `kind` parameter through 'allow or block', but it says nothing about `limit`, its default of 200, or its effect on result size. The schema constraints help, but the description itself adds minimal parameter semantics.

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 a specific verb ('List'), a specific resource ('custom allow or block entries'), and the location/scope ('stored on the DNS server'). The word 'custom' helps differentiate from siblings like `list_blocklists`, and the allow/block wording maps directly to the required `kind` parameter.

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 implies when the tool should be used: whenever an agent needs to see custom allow or block rules on the DNS server. However, it provides no explicit guidance about when to use this tool instead of a sibling such as `list_blocklists`, and it does not mention any exclusions or alternative routing.

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