trmnl_start_preview

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

The description adds useful behavior beyond the annotations: it starts work or changes remote state, returns a reduced-resolution preview not sized for a panel, and identifies the underlying POST endpoint. This is consistent with annotations showing readOnlyHint=false, idempotentHint=false, and destructiveHint=false. It does not add details about reversibility or rate limits, but the annotation coverage lowers that burden.

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 description is front-loaded with the core purpose and is generally efficient. It repeats the render idea once and includes endpoint and authorization notes, but each section contributes useful context without excessive length.

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?

The description covers purpose, high-level behavior, endpoint, and the nature of the returned preview image, which is helpful because there is no output schema. However, for a tool with three parameters, nested body fields, and only 33% schema description coverage, it leaves important parameter guidance and sibling-tool routing incomplete.

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 only 33%, so the description needs to compensate for undocumented parameters. It implies the plugin_setting_id via the endpoint and resource name, but it does not explain the body.size enum values, device_model behavior, or the profile parameter. The parameter guidance is therefore materially incomplete.

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 description clearly states a specific verb and resource: starting a preview render of a plugin instance. It also explains the immediate purpose, checking layout. It does not explicitly distinguish this from nearby preview tools such as trmnl_get_preview or trmnl_project_preview, so it falls short of full sibling differentiation.

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 description gives implied usage context: use it to check layout, and note that the image is reduced resolution and not sized for a panel. However, it does not say when to use this versus trmnl_get_preview, trmnl_project_preview, or device rendering paths, and the authorization warning is not an alternative-selection guideline.

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