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 and idempotent operations, the description explains that this tool returns 'the full ordered downstream chain in a single response' and clarifies how subscribers are included ('Subscribers appear at the same hop as the store they react to'). This provides important implementation details not 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 efficiently structured with zero wasted sentences. It begins with the primary use case, explains the return format, provides sibling tool differentiation, and includes a concrete example - all in four tightly focused sentences that each serve a distinct purpose.

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 and the presence of both comprehensive annotations and an output schema, the description provides complete contextual information. It explains the tool's purpose, when to use it versus alternatives, the structure of the response, and includes a practical example - covering all necessary aspects for effective tool selection and invocation.

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 input schema already documents all three parameters thoroughly. The description doesn't add significant parameter semantics beyond what's in the schema, though it does provide an example using the 'name' parameter. This meets the baseline expectation when schema coverage is complete.

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: 'trace what recomputes if X changes' and 'Returns the full ordered downstream chain in a single response.' It specifically distinguishes this tool from sibling tools like nanostores_store_summary and nanostores_store_subgraph, providing explicit differentiation.

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 ('call this once — not nanostores_store_summary on each downstream store') and when to use an alternative ('Use nanostores_store_subgraph instead when you also need upstream ancestors'). It also includes a practical example to illustrate proper usage.

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