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

Beyond the annotations (readOnlyHint, idempotentHint), the description discloses important behavioral details: partial failure degradation, the 5-30s first-measurement latency for bundlephobia, and the presence of a sources_failed field. It also mentions it fans out to multiple sources and returns a structured summary, adding value beyond annotations.

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?

The description is dense but well-structured. It opens with the core purpose, then usage triggers, then return summary fields, then ecosystem limitations and failure behavior. No redundant sentences; every clause adds new information. Even though longer than minimal, it earns its length given the tool's composite nature.

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?

Given the tool's complexity (multiple data sources, partial failures, no output schema), the description compensates by enumerating the key return fields (summary block, per-advisory detail, links, alternatives) and the failure mode (sources_failed). Combined with rich annotations and a fully-described schema, the agent has sufficient context to select and invoke the tool correctly.

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%: both parameters are already described (package as npm name, version as specific version defaults to latest). The description does not add new parameter-level detail; it only contextualizes them within the overall check. Baseline 3 applies because the schema carries the full semantic load.

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 clearly states the tool's specific purpose: a composite check for whether to add an npm package, fanning out to deps.dev and bundlephobia. It distinguishes itself from siblings by emphasizing the 'ONE call' consolidation and explicitly mentions the data sources and what they provide.

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?

Provides explicit when-to-use guidance: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me"'. Also gives a clear exclusion: 'NPM ecosystem only in v1; PyPI / Maven / Cargo / Go fall under deps.dev:version directly', pointing to an alternative for non-npm ecosystems.

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