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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so safety is covered. The description adds useful context about included fields (geo/ASN, timestamps, flags), but does not describe response format, error behavior, or pagination, which the agent might need to know.

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?

One tight sentence front-loads the core action and identifier, then packs meaningful return-field detail without fluff. Every phrase earns its place.

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 simple single-fetch tool with one fully-documented parameter and annotations covering safety/idempotence, the description is sufficient: it names the resource, the key, and the returned data fields. No output schema exists, so listing the payload contents closes the main gap.

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 describes fingerprint as the device fingerprint. The description confirms it is the lookup key, but adds no format, source, or validation details beyond the schema, so baseline 3.

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 ('Fetch'), resource ('device'), and identifier ('by fingerprint'). Distinguishes from list_devices by being for a single device, and enumerates the fields returned, leaving no ambiguity.

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?

Clearly implies when to use: when you have a fingerprint and need a single device's details. Does not explicitly name alternatives or exclusion criteria, but the single-vs-plural contrast with list_devices gives adequate context.

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