tia_preview_hmi_design

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

With readOnlyHint=true already supplied, the description still adds real value: it declares the output is offline and self-contained, that no equipment connection occurs, and that rendering is not verified-native. The main unrevealed trait is whether the HTML is returned inline or written to disk, which matters for a 'generate' 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 sentences, front-loaded with the core action and followed by scope caveats. No filler; each sentence adds something an agent could not get from the schema alone.

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 tool with a very large nested schema, no output schema, and no parameter descriptions, the definition is thin on the return artifact (HTML string vs file path) and on the two adapter variants present in the schema. The scoping caveats are complete, but the invocation-relevant detail is not.

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% on a single deeply nested required 'design' parameter, so the description would ideally explain its structure. It partially compensates by naming what the design covers (screen navigation, IO values, press/release buttons), hinting at navigateTo, ioField and momentary semantics, but gives no guidance on adapter variants or required fields.

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 artifact: 'Generate self-contained offline HTML to preview a design,' plus the previewed content (screen navigation, local IO values, press/release buttons). It does not name a sibling such as tia_generate_hmi_design to draw the line between generating a design and previewing one, so it is clear but not fully differentiated.

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?

Usage is only implied by the verb 'preview'. The negatives ('Never connects to equipment', 'not TIA runtime simulation or verified native rendering') clarify what the tool is not, which helps rule out misuse, but there is no explicit statement of when to choose this over tia_generate_hmi_design or the apply/export siblings.

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