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

Read-only safety is already covered by readOnlyHint, but the description adds real behavioral context the annotations don't: store-scoped menus mark unavailable items as NotAvailableHere while unscoped menus report everything as Available, and the two markets differ substantially (~282 US vs ~253 CA with exclusives). It does not cover error or rate-limit behavior, keeping it just short of a 5.

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?

A single dense paragraph that is front-loaded with what the tool returns, then parameter semantics, then market caveats. Every sentence carries information, though the product-field enumeration and the market-count aside could be tightened slightly.

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 two-parameter browse tool with an output schema and read-only annotations, the description supplies everything needed: return shape, how to chain to starbucks_product, parameter sourcing and defaults, cross-market caveats, and the exclusivity of the supported markets. Nothing an agent needs to invoke it 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?

Schema coverage is 0%, so the description carries the full burden and does so: market is documented with its allowed values and default ('us or ca (default us)') and why the choice matters, and store_number is documented with its source and its effect on availability output. This fully compensates for the bare schema.

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 ('Browse Starbucks' full menu as a category tree') and enumerates exactly what the tree contains (categories, child categories, products with product number, form, type, sizes, default size, availability, image). This clearly distinguishes it from siblings like starbucks_product, starbucks_stores, and starbucks_nutrition.

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?

Explicitly routes between tools: 'Pair a product's product_number and form with starbucks_product for full detail including nutrition,' and tells the agent where store_number comes from ('using a store number from starbucks_stores'). It also states when scoping applies and the tradeoff (scoped menu flags NotAvailableHere vs unscoped reports everything Available).

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