Set exit node

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

Annotations cover the safety profile (readOnly=false, idempotent=true, destructive=false, openWorld=true), and the description adds genuinely new context: the operation redirects ALL of the host's traffic and therefore requires user approval. That approval gate is a behavioral trait annotations do not convey, though return-shape and failure modes are only gestured at.

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 the core routing behavior and the clear semantics front-loaded before the warning. No filler; every sentence carries load.

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?

With an output schema present, the description need not explain return values, and it appropriately notes the resulting status plus the approval requirement and clearing behavior. Only the absence of a pointer to sibling discovery tools keeps it short of fully complete.

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%, so both parameters (exitNode, allowLanAccess) are already documented in the schema. The description's mention of passing an empty string to clear merely echoes the schema description rather than adding syntax or format detail.

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?

States a specific verb+resource (route this host's internet traffic through a tailnet exit node), names the underlying CLI command, and clearly distinguishes itself from siblings like tailscale_list_exit_nodes by being the setter rather than the lister.

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 the tool applies (redirecting this host's internet traffic) and covers the clear-via-empty-string case plus the user-approval requirement. It does not, however, point at the sibling an agent should call first to discover available exit nodes (tailscale_list_exit_nodes), leaving that inference to the agent.

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