List devices with label

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

Adds meaningful behavior beyond the annotations: it explains that it reads the device registry over WebSocket, filters on the labels list, and critically that a WebSocket failure returns an error dict rather than raising. That error-handling behavior is not captured by the readOnly/idempotent/non-destructive 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?

Front-loads the purpose, then cleanly separates usage, return shape, and error behavior into labeled fragments. No sentence 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?

Given the annotations, 100% parameter coverage, and available output schema, the description supplies all remaining context: when to use it, what it returns, and how failures manifest. Nothing needed for correct invocation is missing.

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 schema already documents label_id, including where to obtain it from labels_list_labels. The description reinforces the filter meaning but adds no syntax or format detail beyond what the schema provides, so baseline 3 is appropriate.

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 precise verb and resource: list devices currently holding a given label. It clearly distinguishes itself from siblings such as labels_list_entities_with_label and devices_list_devices by naming the exact filter relationship.

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?

Provides an explicit 'Use when' scenario ('finding everything tagged with one label, e.g. before a bulk action'), which gives a clear context for invocation. It does not name when-not-to-use or explicitly contrast with the entity-label sibling, so it falls short of the top score.

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