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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds meaningful complementary context: 'Static, free, no prices' tells the agent this is a non-mutating, zero-cost lookup and that pricing must be sought elsewhere. It does not describe pagination or response shape, but for a static reference read that is a minor gap.

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 scope of the inventory in the first sentence and the routing rule in the second. The mid-sentence enumeration is dense but each item plausibly maps to a value domain the caller needs, so it earns its space; slightly list-heavy but not padded.

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?

There is no output schema, so the description must carry the return-value burden — and it does, enumerating the categories of options returned, including the product line caveat (Brick Premium only, 60 mm larch snap-in panels and connector pins). With zero parameters and annotations covering the safety profile, nothing an agent needs to call this 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?

The tool takes zero parameters, so the baseline is 4. The description usefully characterizes the content the caller receives (shapes, dimension keys, size presets, enumerated value sets), which is the closest analogue to parameter meaning for a no-arg reference 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?

The description names a concrete inventory (bed shapes with dimension keys and example sizes, plot shapes and size presets, house/entrance/style/wants values, limits, product line) rather than restating the title. It explicitly contrasts itself with studio_pricing_quote and studio_create_design, so the agent can distinguish it without opening any sibling 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?

It states the trigger condition directly: 'Call it first when unsure what values are allowed.' It also carves out the exclusion — this tool carries no prices, and pricing belongs to studio_pricing_quote or studio_create_design — giving both when-to-use and when-not-use guidance.

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