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

Annotations only give write/non-idempotent/non-destructive. The description adds substantial behavior the annotations cannot convey: scripts and event handlers are stripped, remote images are fetched once with a cap of 8, the design is only applied if the user agrees, and the response may include notes about what will not work as intended.

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 purpose and the confirmation flow, followed by the prerequisite and then dense but useful template details. It is one long run-on paragraph, but the volume is justified by 0% schema coverage; little of it is filler.

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 complex, mutation-style tool with no output schema and no parameter descriptions, this covers template syntax, CSS variables, image fetching limits, sanitization behavior, and the confirmation/preview flow. An agent has enough to author a valid design call without opening the sibling design_guide.

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 coverage is 0%, so the description carries the full burden. It thoroughly explains front_html, back_html (template syntax, conditional blocks, image binding), card_css and site_css (their scopes and available CSS variables), but says nothing about the required `name` parameter beyond its obvious meaning.

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: it creates a visual 'look' for Ordkort cards and returns a preview link with a confirmation step. This is clearly distinct from deck-related siblings like create_deck, though it never names an alternative to contrast against.

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?

'Read design_guide first' is an explicit, actionable prerequisite that most definitions lack. It does not state when *not* to use this tool or name any alternative path, so it stops short of full routing guidance.

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