plc_values

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

Annotations only carry openWorldHint=true, so the description bears most of the behavioral burden. It usefully discloses automatic type coercion based on ST declarations, but says nothing about write failures, permissions, or reversibility of the write path, which is a notable gap for a mutation-capable tool.

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, front-loaded sentences with no filler; the capability and the channel-format constraint come first. Tight and readable, though it could be even more economical.

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 five-parameter dual read/write tool with full schema coverage and no output schema, the description covers the essentials of invocation. It is missing behavioral detail around write semantics and error handling, so it is adequate but not complete.

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 all five parameters are already documented, including the 'ObjectName.ChannelName' format and per-action applicability. The description only restates the channel format and adds the type-coercion note, so it earns the baseline rather than adding new parameter meaning.

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 pair (read/write) and resource (live channel values on a running PLC), so the agent immediately knows the capability. It does not, however, differentiate itself from siblings like control_plc or plc_diagnostics, leaving overlap ambiguous.

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 phrase 'on a running PLC' implies a precondition and the read/write framing hints at when each action applies, but there is no explicit when-to-use/when-not or routing to alternatives such as control_plc. Usage is only inferable.

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