Nanostores MCP

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

The annotations already provide readOnlyHint=true, idempotentHint=true, and openWorldHint=false, which cover safety and idempotency. The description adds valuable context about what information is returned (kind, file location, direct subscribers, first-level derived relations) and provides a concrete example of parameter usage, which enhances understanding beyond the 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 three sentences: the first states the purpose and scope, the second provides usage guidance and alternative, and the third gives a concrete example. Every sentence adds value with zero wasted words, making it easy to parse and understand.

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 that annotations cover safety and idempotency, schema coverage is 100%, and an output schema exists, the description provides complete contextual information. It explains what the tool returns, when to use it, and provides an example, making it fully adequate for an agent to understand and invoke this tool correctly.

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 already fully documents all parameters. The description adds some semantic context by explaining that it accepts 'store id or name' and providing an example, but doesn't add significant meaning beyond what's in the schema. This meets the baseline of 3 for 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 tool's purpose: to provide details about a specific store including its kind, file location, direct subscribers, and first-level derived relations. It uses specific verbs ('summarize') and resources ('store'), and distinguishes itself from the sibling tool nanostores_store_subgraph by specifying it's for single-level details rather than multi-hop dependency chains.

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 when you need details about a specific store' and 'For multi-hop dependency chains use nanostores_store_subgraph instead.' It clearly defines the context and provides a named alternative for different use cases.

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