Tailscale preferences (this host)

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: the exact CLI invocation, the availability-while-Stopped behavior, and the shape of returned fields.

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 terse clauses, front-loaded with the verb and resource, then the mechanism and availability caveat. No wasted words.

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 no output schema, the description compensates by naming representative returned fields (AcceptRoutes, AcceptDNS, ExitNode, Hostname, RunSSH, ShieldsUp), so the agent knows what comes back. Nothing needed to call it correctly is missing.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the schema coverage is trivially 100%. Baseline for a parameterless tool is 4.

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 (Return), resource (this host's current effective Tailscale preferences), and even the underlying command (`tailscale get --json`). An agent can immediately distinguish it from the sibling tailscale_set_prefs and from status-style tools.

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?

Gives a concrete usage condition — 'works even while Stopped' — which tells the agent when this tool is still valid. It does not explicitly name tailscale_set_prefs as the write alternative, but 'Read-only' makes the read/write split clear enough.

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