Effective system policy (local)

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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so safety is covered. The description still adds real context beyond them: the policy sources (MDM/GPO/registry) and the precise scope boundary versus device posture, which is the main confusion risk for this tool.

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 compact sentences with the resource and its sources front-loaded, followed by the usage condition and the scope caveat. Every clause earns its place; nothing is redundant with the annotations or schema.

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 zero parameters, no output schema, and a full annotation set, the description carries exactly the load it needs to: what is listed, where the policy comes from, when to reach for it, and what it is not. Nothing needed to call it correctly is absent.

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 no parameters, so there is no parameter semantics to explain; baseline for a 0-param tool is 4. The description correctly does not invent parameters and instead spends its words on scope.

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?

Specific verb (List) plus precise resource (effective LOCAL system policy applied to Tailscale via MDM/GPO/registry), and it names the underlying CLI command. It also actively disambiguates from the nearest confusable concept ('NOT Tailscale device posture'), so an agent can place it without opening the 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?

Gives an explicit triggering scenario: use it to explain a preference that a set/up change did not persist, which implicitly routes the agent here after failures from the set_* siblings. It does not name those sibling tools directly, so the alternative selection is inferred rather than stated.

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