Set Tailscale preferences

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

Annotations already declare idempotent, non-destructive, open-world behavior, but the description adds real value beyond them: the write is incremental/partial (unspecified prefs are left untouched) and no full flag set is required, which is precisely what an agent needs to avoid clobbering settings. It does not warn about the connectivity impact of prefs like shieldsUp, but that is a minor omission given annotation coverage.

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 tight clauses with zero filler, and the scoping statement ('no connect/disconnect, no complete-flag-set requirement') is front-loaded where it matters most.

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?

For a zero-required-param mutation tool with annotations and an output schema (so return values need not be explained), the description covers purpose, scope, and sibling routing. The remaining gap is that the set of settable preferences is left entirely to the schema, which an agent could underestimate for an 11-param tool.

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?

Eleven parameters with only 36% schema description coverage, and the description names none of them — not even the boolean/string shape or that booleans toggle on/off. It only gestures at the class ('benign prefs'), so it fails to compensate for the coverage gap and adds little meaning beyond the schema.

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 and resource ('Incrementally change one or more preferences via `tailscale set`') and immediately scopes it away from connect/disconnect and the full-flag-set semantics. It also names the sibling tools (exit-node, routes) that own the excluded settings, so an agent can distinguish it from tailscale_set_exit_node and tailscale_set_routes without opening any schema.

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?

Explicitly says when this tool applies (partial, single-or-multiple prefs, no complete flag set needed) and when it does not (exit-node and route changes belong to dedicated tools). It stops short of telling the agent to read current state with tailscale_get_prefs first, so there is one obvious inference left.

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