read_opcua_nodes

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

Goes well beyond the readOnly/idempotent annotations: it explains the single-round-trip batching behavior, that each node returns its own record with value, data type, status code and both timestamps, and critically that a rejected node surfaces as a per-node 'Bad…' status rather than failing the whole call. That partial-failure semantics is exactly the kind of detail an agent cannot infer from structured fields.

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?

Four sentences, front-loaded with the action and the batching rule, then the return shape, then partial-failure semantics. The aside about quality and age ('a bare number carries neither') is rhetorical padding but does justify the returned metadata, so the cost is small.

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?

Covers everything an agent needs before calling: what it reads, how to batch, what comes back per node, and how failures are represented. With an output schema present and annotations declaring the safety profile, the remaining details are already structured.

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 coverage is 100%, so the node ID format, the 500-item cap and the include_write_access cost model are already fully documented in the schema. The description reinforces the batching intent of node_ids but adds no format or constraint detail beyond the schema, so the baseline 3 applies.

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 and resource ('Read the current value of one or more OPC UA nodes in a single request') and scopes it as a single batched read, which clearly separates it from siblings like read_opcua_history, browse_opcua_nodes, and subscribe_opcua_nodes.

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?

Gives a concrete usage rule — 'Pass every node you need in one call' — and quantifies the benefit (fifty nodes, one round trip), which tells the agent to batch rather than loop. It never explicitly names an alternative tool or states when not to use this one (e.g. for historical values or continuous monitoring), so it stops short of full guidance.

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