card_builder_design_for_intent

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

With no annotations provided, the description carries full burden. It discloses that the tool combines three sources and that the output is small, but does not detail any side effects, performance, or error behavior. For a non-destructive advisory tool, this is adequate but not exceptional.

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 3 sentences, each with a clear function: purpose, composition, and guidance. No fluff, well-structured and front-loaded.

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?

Given the existence of an output schema, the description does not need to detail return values. It mentions the output contains pattern, template, and checklist. It also references optional parameters. It could clarify 'domain' and 'entity_id' further, but in context of Home Assistant card building, it is reasonably complete.

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%, so description must compensate. It adds meaning: 'free-text intent' clarifies intent is natural language, and 'optional domain/entity_id' indicates optional scoping. However, it does not explain what domain or entity_id represent beyond the names. Adds some value but not comprehensive.

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 the tool's purpose: 'recommend the best design pattern, the underlying template, and a checklist' given a free-text intent. It uses specific verbs like 'recommend' and 'combines', and distinguishes itself from siblings by referencing other tools for richer detail.

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 provides guidance on when to use this tool and when to use alternatives: 'The reply is purposely small — pull richer text via design_principles() or get_design_pattern(name) if needed.' This implies this tool is for a quick recommendation, while other tools are for deeper dives. It does not explicitly state when not to use it, but the guidance is clear.

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