Nanostores MCP

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false. The description adds valuable behavioral context beyond these annotations: it explains the BFS algorithm with configurable radius, provides a practical starting point (radius=1), warns about performance implications on highly connected hub stores, and gives concrete usage examples. No contradictions with annotations exist.

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 opens with clear usage differentiation, states the core purpose, explains key behavioral aspects (radius usage and hub store considerations), and provides concrete examples. Every sentence adds value and is appropriately front-loaded with the most important guidance.

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 properties (read-only, idempotent), schema coverage is 100%, and an output schema exists (so return values don't need explanation), the description provides excellent contextual completeness. It addresses when to use the tool, behavioral nuances, practical usage tips, and examples - exactly what's needed beyond the structured data.

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 four parameters. The description adds some semantic context about the radius parameter (recommending starting with radius=1 and explaining when to increase it), but doesn't provide additional meaning for storeId, name, or projectRoot beyond what's in their schema descriptions. 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: to get both upstream sources AND downstream dependents together (the store subgraph) using BFS within a configurable radius. It specifically distinguishes this from the sibling tool nanostores_store_impact, which provides only the downstream causal chain. The verb 'get' combined with the resource 'store subgraph' is specific and well-differentiated.

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. It directly states: 'If your question is "what recomputes downstream when X changes?", use nanostores_store_impact instead' and 'Use this tool only when you need both directions: upstream sources AND downstream dependents together.' This includes clear when-not-to-use criteria and names the alternative tool.

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