hmi_scan

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: the file scope it walks and the root resolution fallback (project.hmi_root, else project root). It says nothing about cost, scale, or whether an index artifact is persisted, which matters for a tool named 'scan/index'.

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 tight sentences, what-it-does first, default behavior second — nothing superfluous. The embedded glob notation (%s%PLC1.X%/s%) is telegraphic and slightly opaque, but it is compact rather than padded.

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?

With an output schema present, return values need not be described, and the one parameter is fully covered. The remaining gap is routing: nothing explains how this scan relates to hmi_bindings/hmi_vs_runtime, so an agent choosing among HMI tools is under-informed.

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 0% — the single 'root' parameter is only typed as string|null with default null. The description compensates well by explaining that root falls back to project.hmi_root and then to the project root, which the schema does not capture at all.

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+resource: 'Index HMI symbol bindings', and enumerates the exact file families it covers (TE2000 .view/.content/.usercontrol/.json and TcVIS). It does not, however, distinguish itself from close siblings like hmi_bindings or hmi_vs_runtime, so an agent must infer which one to pick.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no routing to the obvious sibling tools (hmi_bindings, hmi_vs_runtime). The only usage-adjacent information is the root default fallback, which is parameter behavior rather than invocation guidance.

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