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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description nonetheless adds a genuinely useful behavioral detail absent from structured data: the response is JSON via the Accept header, not HuJSON, which affects how an agent parses the result. It omits auth scope requirements and any rate-limit or caching behavior.

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 tight sentences: the purpose and output format come first, and the raw endpoint reference is a compact trailing clause. Nothing is redundant or padded.

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 usefully discloses the response encoding (JSON rather than HuJSON), which is exactly the kind of return-value context an agent needs. What is missing is permission/scope expectations and any note that the endpoint may fail for tailnets without ACLs.

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 description coverage is 100% with a single optional 'details' flag, so the schema already explains the parameter fully. The description says nothing about the parameter, so it adds no meaning beyond the schema — the baseline 3 for high coverage applies.

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 (Get) and resource (the tailnet's ACL/policy file) and even names the underlying REST endpoint GET /tailnet/{tailnet}/acl. No sibling tool touches policy files, so the agent can distinguish it immediately.

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?

Usage is implied by the read-only 'Get' framing and the REST endpoint mapping, but there is no explicit when-to-use or when-not-to-use guidance, nor any note about what to do if the policy is empty or access-restricted. No sibling alternative exists to route to, which limits how much guidance is feasible.

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