unsubscribe_opcua_nodes

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

Annotations declare readOnlyHint=false and destructiveHint=false, and the description adds real behavioral detail beyond them: buffered data is discarded but returned so it can be read one last time, and an unknown ID causes an error with no cancellation happening at all (all-or-nothing failure). It doesn't cover authorization requirements or whether cancellation is awaited/bounded by a timeout, but the failure semantics are unusually well disclosed.

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?

Three short sentences, front-loaded with the action, then return content, then failure behavior. No filler or repetition of the name.

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?

An output schema exists so return values need not be explained, and the description still covers the key mutation semantics (discard + last-read return, atomic failure on invalid IDs). For a one-parameter mutation tool this is close to complete; only auth/permission and concurrency caveats are absent.

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% and the single parameter is documented there, including the ID format and origin (subscribe_opcua_nodes, list_subscriptions). The description only echoes 'one or more active', which the schema already enforces via minItems 1; no additional semantics are added.

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 ('Cancel one or more active data-change subscriptions'), plus the exact consequence ('discard what they had buffered'). That is clearly distinguishable from subscribe_opcua_nodes, list_subscriptions, and the read_* siblings.

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 context is clear: this is for tearing down active subscriptions, and the ID source is implied by 'active'. However, it never names an alternative or an exclusion (e.g., when to prefer list_subscriptions to check state first, or what to do for a non-existent ID besides expecting an error).

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