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

With annotations already conveying readOnlyHint=false and destructiveHint=false, the description adds genuinely new behavioral context: the 100-credit cost per paid raster/SVG batch, fonts being free, the dry-run default, and the do-not-modify-quote contract. This goes well beyond what the annotations alone disclose.

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 sentences, each earning its place: the first front-loads the purpose and flow, the second explains the pricing/batch model, the third adds two critical constraints. No filler or redundancy.

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?

This is a complex 5-parameter tool with nested objects, a two-phase quote flow, and no output schema, yet the description never describes what the dry-run returns (estimatedCredits, quote structure, batch breakdown shape) nor the explicit confirmation/consent step before generation (left to the dryRun parameter description). Purpose and pricing are well covered, but for this complexity the flow details are 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?

With 80% schema coverage, the baseline is 3, but the description adds interaction-level semantics the schema lacks: how the quote relates to dryRun and request (dry-run produces a signed quote that must be passed back unmodified) and the batch-pricing model. It does not mention packId or idempotencyKey, but the schema already covers those 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?

The description states the core flow with a specific resource: get a cost preview for a UI pack component list, then generate using a signed quote. The dry-run/quote mechanism clearly distinguishes it from siblings like create_ui_pack or get_ui_pack, though it never names an alternative explicitly.

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 first sentence gives an explicit invocation pattern: preview first, then generate with the returned signed quote. 'Defaults to dry-run' and 'never alter the quote' add clear constraints on how to call correctly. However, it does not name when-not-to-use cases or alternative siblings.

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