Nanostores MCP

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

The description adds valuable behavioral context beyond what annotations provide. While annotations indicate read-only, idempotent, and closed-world behavior, the description reveals that this tool returns 'a compact summary instead of full store/subscriber lists' and uses 'same scan data, smaller response.' This provides important implementation details about response size and data source that aren't captured in 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 perfectly concise and well-structured. Two sentences efficiently convey the tool's purpose, what it returns, when to use it, and when to use the alternative. Every word serves a clear purpose with no redundancy or unnecessary elaboration.

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, comprehensive annotations (readOnlyHint, idempotentHint, openWorldHint), and the presence of an output schema, the description provides complete contextual information. It explains the tool's purpose, differentiates it from alternatives, and describes the response format, which is sufficient since the output schema will handle return value details.

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 and only one optional parameter, the schema already fully documents the 'projectRoot' parameter. The description doesn't add any additional parameter semantics beyond what's in the schema, so it meets the baseline expectation but doesn't provide extra value in this dimension.

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 purpose: providing a 'quick overview of Nanostores usage in the project' with specific content elements (store kind distribution, top directories, hub stores ranked by connectivity). It explicitly distinguishes this from its sibling 'nanostores_scan_project' which provides complete lists, making the distinction unambiguous.

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 explicit guidance on when to use this tool versus alternatives: 'Use this for a quick overview...' and 'Use nanostores_scan_project when you need the complete list of stores and relations.' This clearly defines the use case context and names the specific alternative tool for different needs.

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