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

Annotations already declare the safe read-only profile, and the description adds substantial non-obvious behavior: values carry no timestamp and their age is unknowable, recordUpdatedAt is not a heartbeat, no online/offline ping exists so 'last seen' must never be reported, empty deviceEnvironment is itself a finding, and card reader data is read-only. These are exactly the nuances that prevent agent hallucinations.

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-loaded with scope and identity before the field-by-field reading guide, and almost every sentence carries troubleshooting value. It is on the long side for a single-parameter read, but the length is driven by the absence of an output schema rather than padding.

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?

There is no output schema, so the description correctly takes on the burden of explaining return fields (kind, deviceId, enrolledBy, createdAt, deviceEnvironment, recordUpdatedAt) and their interpretation. It also fills the sibling gap by pointing to the Terminals screen for card reader actions. Nothing needed to call or interpret this tool 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 single parameter is already documented in the schema as 'Station id from get_stations — not a name'. The description repeats that constraint ('Takes the station id from get_stations, never a name') without adding format, length, or lookup detail beyond it. Baseline 3 applies when the schema carries the parameter semantics.

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+resource ('Everything about ONE station'), scopes it to a single station versus the sibling list tool, and explicitly separates itself from hub_get_stations by stating where the id comes from. An agent can distinguish it from hub_get_stations, hub_create_station, hub_delete_station and hub_rename_station without opening any schema.

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?

Gives explicit trigger phrases ('the till will not connect', 'it will not print', 'the card reader is not working') and an explicit when-not: card reader pairing/unpairing happens on the Terminals screen of the cabinet, not through any tool. It also names hub_get_stations as the required upstream call, which is exactly the routing guidance an agent needs.

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