tailnet_devices

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

With no annotations, the description carries the full burden, and it does add real behavioral context: the two possible data sources and the fallback logic, plus an enumeration of the fields returned (online/last seen, OS, version, update availability, key expiry, tags, host/panel mapping). It stops short of stating permissions or explicitly labeling the operation read-only.

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?

A single dense sentence, front-loaded with the resource scope before the parenthetical about data source. It packs a lot of field information without wasted words, though the parenthetical interrupt is slightly awkward.

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 read-only listing tool with no output schema and two optional filters, the description covers the data source and the content of each returned record, which is enough for an agent to call it correctly. Missing only explicit safety/permission framing, which is minor here.

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% (both `filter` and `offlineDays` are documented in the schema), so the baseline is 3. The description adds no meaning for either parameter beyond what the schema already provides.

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 states a specific resource (every device of the tailnet) and enumerates the per-device attributes returned, so an agent can distinguish it from siblings like tailnet_join or tailnet_device_remove. It does not explicitly name those siblings, but the enumeration scope makes its role unambiguous.

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 only implied: the agent infers it should call this to inventory devices. The parenthetical explains the data-source fallback (TAILSCALE_API_KEY vs local `tailscale status`), which is useful context, but there is no explicit when-to-use, when-not-to, or named alternative.

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