validate_write

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

With no annotations, the description carries the full burden and does so: it discloses that nothing is written, that no device connection occurs, the specific rule families applied (access, range, scale, single-register, SunSpec range, gates/vetoes, side effects, readback), and the three possible verdicts plus reasons. Reversibility and safety are fully implicit in the read-only framing.

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 critical fact (validation without writing) is front-loaded, and the closing sentences are tight. The middle sentence is a long parenthetical enumeration that is dense but each item adds distinct information, so little is wasted.

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 4-parameter tool with full schema coverage, no annotations and no output schema, the description supplies the return contract (ok / ok_with_warnings / reject with reasons) and the behavioral guarantees an agent needs before calling it. Nothing material is missing.

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 baseline is 3; the description adds real meaning on top by revealing that function-code choice is constrained per address range ('0x06 only for 11300-11303, 11320-11324, 11330, 11057, 11254') and that value scaling and side effects (e.g. 0x5A5A on 12026) are interpreted against the register, not applied blindly.

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 opening clause states a specific verb and resource ('Check a planned write against the documentation') and immediately scopes it with 'WITHOUT writing anything', which separates it from the sibling mutation/lookup tools. The enumerated checks that follow confirm exactly what class of validation is performed.

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?

It establishes the context of use clearly: a pre-write dry-run check, with the caveat 'Guidance only; this server never connects to a device and never writes registers', which tells an agent this is not a substitute for execution. It stops short of naming alternatives (e.g. get_register for plain lookup) or stating explicit when-not-to-use conditions.

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