list_devices

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

The description discloses a genuine write side effect ('records the sighting in the local registry'), which conflicts with the readOnlyHint=true annotation declaring the tool does not modify its environment. Per the rules this contradiction forces a 1, even though the latency warning ('takes a few seconds; the router is slow here') is otherwise useful context.

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 short sentences, front-loaded with what is returned and followed by the side effect and latency caveat. No filler; every clause carries information an agent would not get from structured fields.

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 and an output schema present, the description need not explain return values, and it supplies the two facts an agent most needs: latency and the registry side effect. The only gap is that it never positions itself against the many sibling device-inspection tools.

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 zero parameters, so the baseline is 4 and there is nothing further the description could add about inputs. It instead usefully hints at what the output merges (nicknames, owners, tags, vendor).

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 and scope: every device currently attached to the router, merged with nicknames, owners, tags and vendor. The phrase 'right now' implies a live snapshot, which loosely separates it from siblings like device_history and known_devices, but no sibling is named explicitly, so the differentiation is only inferential.

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 rather than stated: an agent can infer this is the tool for the current live device snapshot versus historical or known-device lookups. There is no explicit when-to-use, when-not-to-use, or named alternative such as known_devices or device_history.

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