tailscale_update_acl

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

Annotations include idempotentHint=true and openWorldHint=true. The description adds context beyond annotations by explaining the need for ETag to prevent overwrites and the format requirement (HuJSON). No contradictions with annotations.

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 sentences with no redundant information. Each sentence earns its place: first states purpose and format, second provides critical workflow instructions. Highly efficient.

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?

The description lacks information about the return value (e.g., success message or updated policy). Given no output schema, the agent might need to know what to expect. Also, it does not mention that the update replaces the entire policy.

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%, and the description adds meaning: it explains that 'policy' accepts the full policy as a string to preserve formatting, comments, and trailing commas (HuJSON), and reiterates the purpose of 'etag' for conflict prevention.

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 clearly states the tool's purpose: 'Update the ACL policy for your tailnet.' It specifies the input format (HuJSON string) and distinguishes from sibling tools like tailscale_get_acl by emphasizing that the full policy must be passed.

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 provides explicit workflow guidance: 'You MUST pass the ETag from tailscale_get_acl to prevent overwriting concurrent changes. Always get the current ACL first...' It explains when and how to use the tool, but does not mention alternatives like tailscale_validate_acl or tailscale_preview_acl.

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