tailscale_set_split_dns

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

With destructiveHint=true already present in annotations, the description still adds specific value by stating exactly what is destroyed: the entire split DNS configuration. This is meaningful behavioral context beyond the generic annotation.

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?

Three short sentences with no filler. The most important behavioral distinction ('Replaces the entire split DNS configuration') is included prominently, and every sentence contributes useful information.

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?

There is only one required parameter, and the schema fully documents it. The description covers the key destructive replacement behavior, and no output schema exists, so return-value documentation is not required. An agent has enough information to invoke the tool correctly.

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 description coverage is 100%, and the parameter schema already explains the map-of-domain-to-nameserver-list structure with an example. The description's 'Maps domains to specific nameservers' adds little beyond what the schema provides, so baseline 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 uses a specific verb ('Set') and resource ('split DNS configuration'), then explains the behavior ('Maps domains to specific nameservers'). The sentence 'Replaces the entire split DNS configuration' also distinguishes it from tailscale_update_split_dns, so an agent can tell them apart without opening schemas.

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 clearly communicates that this call replaces the whole split DNS configuration, which is the key context for choosing it over an incremental update. However, it does not explicitly name the alternative or state 'use this when replacing all entries, not for partial updates,' so it stops short of fully explicit routing guidance.

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