SMART attribute report for one disk

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

Annotations already declare readOnly=true and openWorld=true, yet the description adds substantial context: the endpoint is keyed on serial and rejects other identifiers with N300403, NVMe drives report no classic attributes, and the response includes server-supplied warning/fault text. This is real behavioral disclosure beyond the structured 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?

Well front-loaded with the core purpose first, then input constraints, then output shape, then interpretation guidance. Slightly redundant in enumerating the return object fields even though an output schema exists, but no sentence is wasted.

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 one-parameter read tool with annotations and an output schema, this covers everything needed: valid input source, invalid input failure, return contents, NVMe exception, and which attribute ids matter. Nothing required for a correct call 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% with a single required 'sn' parameter, so the schema carries the baseline. The description adds genuine meaning: the parameter must be a serial (not a pool id or /dev name) or the call fails, and where to obtain a valid value.

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 and resource ('Return the full SMART attribute table for one disk') and explicitly distinguishes itself from the sibling zspace_disks, which is positioned as the quick-overview tool. An agent can route correctly without opening either 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 the prerequisite ('Get serials from zspace_disks first'), the wrong-input failure mode (pool id or /dev name returns N300403), and the alternative for a different need ('For a quick health overview use zspace_disks'). Explicit when-to-use and when-to-use-something-else.

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