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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description genuinely adds beyond that by disclosing that an update is a no-op and that no settings are settable, which prevents a wasted or harmful call. It stops short of explaining why the tool is exposed at all.

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?

Three short sentences with the constraining fact front-loaded, which is efficient. Two of the sentences restate the same point (nothing is settable / empty update does nothing) and the widget reference sits last, so there is minor redundancy rather than tight single-purpose messaging.

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?

An output schema exists, so return values need not be described, and the description does cover the no-op nature of the tool. Given a required nested parameter, 0% schema coverage, and a name implying mutation, it still leaves unclear what an agent should do if it does call this tool and whether a non-empty 'set' is ever valid.

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 single 'set' parameter has 0% schema description coverage, so the description must carry the load. It only obliquely explains the parameter via 'an empty update is a no-op', without saying that 'set' must be an empty object or listing any permitted keys, leaving the agent to reverse-engineer the schema's additionalProperties: false constraint.

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 defines the tool almost entirely by negation: it says no primitive account settings are available and that an empty update is a no-op, but never states what update_plugin_settings actually does or why it exists. The only positive information is a routing hint ('device preferences are changed in the widget'), which is more about a sibling than this tool.

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?

It implies the tool should effectively never be invoked ('an empty update is a no-op') and points to the widget for device preferences, which is a partial alternative-routing hint. However, there is no explicit 'use this when / do not use this when' statement, and the implied 'don't call me' guidance is left for the agent to infer.

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