tailscale_derp_map

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

The description discloses the return values: the derpMap field or a 'not configured' message, which is sufficient for a read-only getter. It does not explicitly state that it is read-only or requires authentication, but the verb 'Get' strongly implies no side effects. Without annotations, this is adequate.

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?

The description is two sentences, zero waste, front-loaded with the purpose, and efficiently conveys the tool's behavior and return values.

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?

Given no parameters and no output schema, the description explains the return values (derpMap or 'not configured' message) completely. It is sufficient for an agent to understand and invoke this simple tool correctly.

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 has no parameters, so baseline is 4. Schema coverage is 100% (vacuously). The description does not need to add parameter information.

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 retrieves the custom DERP relay map from the tailnet's ACL policy, using a specific verb ('Get') and resource. It distinguishes from siblings like tailscale_derp_map_set (which sets the map) and tailscale_acl_get (which gets the full ACL).

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 implies usage when you need the custom DERP map specifically, not the full ACL. However, it does not explicitly state when to use versus alternatives or provide exclusion criteria. The context is clear but lacks explicit guidance.

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