List ESPHome devices with LVGL support

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive), so the description's bonus value is the implementation detail: it parses every YAML under /config/esphome/ and tolerates parse errors by skipping bad devices. That is a non-obvious behavior worth disclosing. It doesn't discuss performance or caching, but the key behavioral quirk (error tolerance) is present.

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?

Front-loaded with the definition, then separated into 'Use when', 'Not for', and 'Returns' sections. Every sentence carries information and there is no redundancy with the title.

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?

Covers purpose, usage routing, behavioral quirk, and even summarizes the return shape as {device, pages, page_ids}. With an output schema present, the return summary is a bonus rather than a requirement, and nothing an agent needs to call this no-arg tool correctly 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?

Zero parameters, so the baseline is 4. The description correctly adds nothing misleading about parameters and instead documents the fact that the scan covers all devices under /config/esphome/ with no filtering option, which is the relevant fact for a no-arg tool.

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 resource ('List ESPHome devices whose YAML config has an lvgl: section'), and distinguishes itself from the sibling esphome_list_devices by narrowing to LVGL-enabled configs. An agent can identify the tool's purpose without opening the schema.

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?

Explicit 'Use when' clause gives the trigger condition (finding devices before inspecting/editing pages) and a 'Not for' clause names the alternative (esphome_lvgl_get_pages) with the condition that selects it. Both sides of the routing decision are present.

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