Nanostores MCP

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the agent knows this is a safe, repeatable read operation. The description adds valuable context about what the tool returns (health check data types) and mentions the 'compact' parameter's purpose for 'lower token cost,' which isn't covered by annotations. 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 efficiently structured in two sentences: the first states the purpose and return data, the second provides parameter examples. Every sentence adds value without redundancy, and it's appropriately front-loaded with the core 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 tool's moderate complexity (diagnostic read operation), rich annotations (readOnlyHint, idempotentHint), and the presence of an output schema, the description is reasonably complete. It covers the tool's purpose and key return aspects, though it could benefit from more explicit differentiation from sibling tools to fully guide usage.

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%, so the schema fully documents both parameters (windowMs, compact). The description adds minimal value by providing example parameter structures ({}, {windowMs: 60000, compact: true}) and noting the compact parameter reduces token cost, but doesn't explain parameter interactions or default behaviors beyond what the schema provides.

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 as providing a 'high-level health check of the running app's state management' and lists specific return data (active stores, error-prone stores, unused stores, activity patterns). It distinguishes from some siblings like 'nanostores_ping' (basic connectivity) but doesn't explicitly differentiate from similar diagnostic tools like 'nanostores_store_summary' or 'nanostores_runtime_coverage'.

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 some guidance with 'Use this when you want a high-level health check' and gives parameter examples, but it doesn't explicitly state when to choose this tool over similar siblings (e.g., 'nanostores_store_summary' or 'nanostores_runtime_coverage'). The context is implied rather than explicitly contrasted with alternatives.

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