NPM Sentinel MCP

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

Annotations already provide excellent behavioral coverage (readOnlyHint=true, openWorldHint=true, idempotentHint=true), so the bar is lower. The description adds useful context by specifying that these are 'repository statistics' (presumably from GitHub based on the annotation title), which helps the agent understand what type of data to expect beyond just knowing it's a safe read operation.

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 communicates the core purpose without any wasted words. It's appropriately sized for a tool with good annotation coverage and straightforward functionality.

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 annotations provide excellent behavioral transparency and the schema fully documents the single parameter, the description is reasonably complete for a read-only statistics tool. However, without an output schema and with many similar sibling tools, the description could better specify what 'repository statistics' includes to help the agent understand the return value.

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?

With 100% schema description coverage, the schema already fully documents the single 'packages' parameter. The description adds no additional parameter information beyond what's in the schema, so it meets the baseline expectation but doesn't provide extra value regarding parameter usage or constraints.

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 ('Get repository statistics') and resource ('for NPM packages'), making the purpose understandable. However, it doesn't differentiate this tool from its many siblings (like npmQuality, npmScore, npmTrends) that also provide various package metrics, leaving some ambiguity about what specific statistics are provided.

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 17 sibling tools including npmQuality, npmScore, and npmTrends that likely provide overlapping statistical information, the agent receives no help in selecting the appropriate tool for repository statistics versus other metrics.

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