tailscale_set_split_dns

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

The description discloses the key behavioral trait: it replaces the entire split DNS configuration. Annotations already indicate idempotentHint=true and destructiveHint=false, and the description aligns with them by explaining the replacement behavior. It adds context beyond annotations but could be more explicit about the overwrite effect.

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 very concise with three short sentences. Each sentence contributes a key piece of information: the action, the mapping behavior, and the full replacement behavior. No extraneous text.

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?

Given the tool's simplicity (one parameter, no output schema, good annotations), the description is fairly complete. It explains the purpose and the replacement behavior. However, it could mention that the operation is idempotent (though annotated) or that it overwrites any existing configuration, which is implied but not explicit.

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% for the single parameter 'splitDns', and the schema already includes a detailed description with an example. The tool description does not add additional semantic information beyond what the schema provides, 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 verb 'Set', the resource 'split DNS configuration', and provides specific detail: 'Maps domains to specific nameservers. Replaces the entire split DNS configuration.' This distinguishes it from siblings like tailscale_get_split_dns (get) and tailscale_update_split_dns (update vs replace).

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 usage by stating it replaces the entire split DNS configuration, suggesting it is for full replacements as opposed to partial updates (tailscale_update_split_dns). However, it does not explicitly state when to use this tool versus alternatives, nor does it provide any prerequisites or exclusions.

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