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

Annotations cover read-only, idempotent, non-destructive, closed-world. The description adds meaningful behavior beyond them: the return includes the shared MCP endpoint and explicitly enumerates which tool calls are free versus which require x402 payment. That payment-gating detail is not derivable from annotations and is operationally important.

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?

Two sentences, front-loaded with the core purpose, then the negative scope and the returned payload. Zero filler, every clause carries routing or behavioral information.

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?

There is no output schema, so the description usefully summarizes what comes back (endpoint, free vs paid calls). It could still state format or pagination/versioning, but for a zero-param status tool the level of detail is nearly sufficient.

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?

Zero parameters, so the baseline is 4. The description correctly makes no claims about inputs and instead describes the response payload, which is the relevant information for a param-less discovery tool.

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?

States a specific verb (Return) and resource (bounded service metadata for OPC UA NodeSet Compatibility Gate), and explicitly differentiates from the sibling comparison tool by saying 'do not use it to compare NodeSets'. An agent can select this tool without ambiguity.

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?

Explicitly scopes the usable cases (discover deployment stage, static-analysis scope, production availability, payment status) and names what it is NOT for (comparing NodeSets). This is a clear when-to-use / when-not-to-use statement.

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