VNyan MCP reference guide

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

No annotations are provided, so the description carries the full burden. While it does not explicitly state that the tool is read-only or free of side effects, the phrasing 'reference documentation' clearly indicates an informational, non-mutating operation. It also discloses the behavioral trait of being mirrored as MCP resources, which is useful context. For a simple lookup tool, this is adequate transparency without being exhaustive.

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 two sentences, front-loaded with the core purpose, then quickly covers usage (omit topic to list) and an alternative access path. Every word earns its place; there is no filler or repetition. The structure is efficient and immediately comprehensible.

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?

For a tool with one optional parameter and no output schema, the description covers what content is available, how to get a topic list, and that the same data is also published as resources. It does not specify the exact output format (e.g., plain text vs. markdown), but given the simple nature of a reference lookup, this is a minor omission. Overall, the agent has enough to use the 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?

The schema already fully documents the 'topic' parameter with an enum and a description. The tool description adds value by elaborating on what each topic actually contains (e.g., 'the runtime type-safety gotcha', 'the full bone-name list'), giving the agent a richer sense of what it will get. It also reinforces the omission behavior. This goes beyond the schema's minimal naming and justifies a score above the baseline.

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 identifies the tool as providing long-form reference documentation for the MCP and enumerates the exact content areas (node-authoring rules, bone-name list, settings.json key index, etc.). This is a specific, unambiguous purpose that easily differentiates it from the sibling action tools, which perform operations rather than deliver reference material.

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 implies when to use the tool (when reference documentation is needed) and explains how to operate it (omit 'topic' to list everything, use a topic to fetch specific content). However, it does not explicitly discuss when to choose this tool over alternatives; it only notes that the same content is also available as MCP resources, without guidance on which access method to prefer. This leaves some ambiguity for the agent.

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