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

With no annotations, the description carries the burden and does so reasonably: it discloses a hard scope limit (public registries only), a failure-mode contract ('unsupported provider fields are null'), and the cost model ('$0.002 USDC per successful call') — the latter being critical for an agent deciding whether to call. It omits rate limits and auth/settlement requirements, so not a 5.

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 dense, front-loaded sentence covering scope and outputs, followed by two short constraint/cost sentences. Every clause earns its place, though the output-field list is long enough that it reads as a run-on rather than structured.

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?

There is no output schema, and the description compensates by enumerating the returned fields and their null behavior, plus the pricing/scope constraints. An agent knows what it gets back and what it pays. Only auth/settlement mechanics and pagination (if any) are left unstated.

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 description coverage is 100% with only 3 flat parameters, so the schema already documents package, version, and ecosystem (with enum). The description's mention of 'requested-version existence' vs 'resolved/latest version' implies how the optional version parameter is used, but adds no format or syntax detail beyond the schema. Baseline 3 is correct.

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 ('Normalize ... package reality') and resource ('npm or PyPI package'), then enumerates exactly which facts are resolved: existence, version existence, resolved/latest, staleness, deprecation/yank, license, runtime requirement. Sibling names (domain_preflight, release_asset_resolve) are distinct enough that this is clearly the package-registry variant.

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 real boundary conditions: 'Public registries only' and 'No dependency graph or vulnerability analysis', which tells the agent when NOT to use it. It stops short of naming an alternative tool for the excluded cases, so it falls short of a 5.

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