net_registry_check

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

With no annotations, the description must carry the whole burden; it does disclose the config resolution order and that both TCP reachability and HTTP status are exercised, which tells the agent this performs live network I/O rather than a local read. It stops short of stating side-effect freedom, timeouts, or how failures versus unreachable hosts are reported.

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?

Two sentences, with the target resource and resolution order front-loaded and the triage hint last. Minor friction from the dense parenthetical and the repeated word in "npm registry npm is actually configured to use," but nothing 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 zero-argument network diagnostic with no annotations and no output schema, the description covers what is inspected, how the registry is resolved, and when to reach for it. It leaves the shape of the result (per-endpoint statuses, how the two registries are compared) undescribed, which is the main remaining 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?

The tool takes zero parameters, so there is no parameter semantics to explain and the baseline is 4. The description correctly implies no arguments are needed, since everything is derived from environment and config files.

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?

Names a specific verb (check) and a precise resource: the npm registry actually in effect, resolved in a stated precedence order (environment → ~/.npmrc → official default), plus TCP and HTTP probing of both. This is clearly distinct from the sibling diagnostics (net_proxy_status, net_github_status, net_dns_compare), which cover other layers.

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?

The closing line "npm install failed usually starts here, not at GitHub" gives a concrete trigger condition and explicitly steers the agent away from the GitHub-oriented sibling. It does not say when the proxy, DNS, or doctor siblings would be the better first call, so routing among the rest of the family is left implicit.

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