NPM Sentinel MCP

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

Annotations already provide readOnlyHint=true, openWorldHint=true, and idempotentHint=true, indicating safe, non-destructive operations. The description adds context about comparing 'based on various metrics,' which hints at behavioral aspects beyond annotations, but doesn't specify what metrics are included, how results are presented, or any rate limits. No contradiction with annotations exists.

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 a single, efficient sentence that directly states the tool's purpose without unnecessary words. It's front-loaded with the core action and resource, making it easy to parse quickly.

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 moderate complexity (comparing multiple packages with metrics), lack of output schema, and rich annotations, the description is minimally adequate. It covers the basic purpose but lacks details on output format, metric types, or comparison methodology, which could hinder effective use by an AI agent.

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 the 'packages' parameter clearly documented as 'List of package names to compare.' The description adds no additional parameter semantics beyond what the schema provides, such as format examples or constraints on the number of packages. Baseline 3 is appropriate given high schema coverage.

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 action ('compare') and resource ('NPM packages') with the scope ('multiple' and 'based on various metrics'). It distinguishes from some siblings like npmSearch or npmVersions by focusing on comparison rather than searching or listing versions, but doesn't explicitly differentiate from all alternatives like npmScore which might also involve metrics.

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 description provides no guidance on when to use this tool versus alternatives. With many sibling tools available (e.g., npmScore, npmQuality, npmTrends), there's no indication of when comparison is preferred over individual metric tools or what specific use cases this tool addresses.

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