Check for a newer version

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

Annotations declare readOnlyHint and openWorldHint, and the description adds real substance beyond them: exactly one request to registry.npmjs.org, nothing about the user or their mail is transmitted, and nothing is installed—updating is deliberately left to the person. Those disclosures about network reach, privacy, and no self-update are precisely what an agent needs before invoking an open-world call.

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?

Purpose is front-loaded in the first clause, and the bolded caveat earns its emphasis because it prevents an accidental network call. The second sentence is long and carries several clauses, but each adds distinct information rather than restating the schema or annotations.

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 zero-parameter, no-output-schema tool this covers intent, trigger, network behavior, and outcome (install instructions). The one gap is failure behavior—nothing says what happens if the registry is unreachable or the server is already current—minor for a low-stakes advisory call.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. It does at least signal that any scoping (which registry, which version) is handled internally rather than by the caller.

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: asks the npm registry whether a newer version exists and reports how to install it. It also implicitly separates itself from every sibling, all of which are mail operations, by noting this is the only tool that contacts anything beyond the local Proton Mail Bridge.

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 an explicit positive trigger ("call it when the user asks about updates") and an explicit exclusion ("rather than by habit"), which is the key failure mode for a version-check tool. No sibling names an alternative, but none of the listed mail tools could substitute, so the missing alternatives clause costs little.

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