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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description contributes the navigation model (one level at a time, is_location marker semantics, path continuity from a previous response's children[].path), which is behavior an agent can't infer from the annotations or a single-parameter schema.

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?

Two densely packed sentences that are front-loaded with the browsing model and end with the sibling routing rule. Nearly every clause earns its place; the example paths are load-bearing rather than filler, though the wording is compact enough to require careful reading.

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 single-optional-parameter, read-only browse tool with an output schema, the description supplies everything else needed: hierarchy depth, path derivation from prior responses, how to recognize restaurant nodes (is_location), and the correct next tool. Return-value details are legitimately delegated to the output schema.

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 100% and the schema already documents path, but the description reinforces the semantics with concrete formats ("il", "il/chicago") and states what omitting the parameter yields (the root state index). This is slightly more than the schema provides, though the schema carries most of the load.

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 (browse/enumerate) and resource (Five Guys US restaurant directory) and explains the three-level hierarchy: states at root, cities under a state path, restaurants under a city path. It explicitly names the sibling alternatives (fiveguys_store for restaurants, fiveguys_search/fiveguys_nearby for query or coordinate lookups), so an agent can distinguish it from those tools without opening any 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?

Gives explicit routing: use this tool to enumerate or browse, use fiveguys_search/fiveguys_nearby to find by query or coordinate. It also states the hand-off rule that children marked is_location are restaurants whose path should be passed to fiveguys_store, covering when-to-use and the follow-up call.

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