tailscale_update_split_dns

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

Annotations already declare mutability, idempotency, and non-destructive nature. Description adds detail about merge semantics and removal via empty array, aligning with openWorldHint and idempotentHint. No contradictions.

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?

Two concise sentences that cover the core behavior and a special case. No wasted words; front-loaded with action and resource.

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?

Covers the essential behavior for a partial update tool with a nested parameter. Lacks mention of prerequisites or error conditions, but annotations compensate for many behavioral aspects. Good for the complexity level.

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 covers all parameter details with description and example. Description adds semantic value by explaining merge behavior and removal via empty array, going beyond the schema alone.

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?

Clearly identifies the verb (partially update), resource (split DNS configuration), and the specific merge behavior. Distinguishes from sibling tools like tailscale_set_split_dns which likely replaces the entire config.

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?

Explains when to use (partial updates, merging domains) and how to remove a domain (set to empty array). Lacks explicit mention of alternatives like tailscale_set_split_dns for full replacement, but the partial update description implies its use case.

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