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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds only the provenance note about where ids come from; it says nothing about output shape, caching, or failure behavior, and an output schema exists so return values need not be explained.

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?

One compact sentence with no filler, front-loading the resource and the lookup key. The phrasing 'looked up directly by store id' is slightly awkward but costs nothing.

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-parameter read-only lookup with a fully documented schema and an output schema, this is nearly complete: the agent knows the key, its source, and the safety profile. Only the absence of any routing hint away from arbys_menu/arbys_directory leaves a small gap.

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 description coverage is 100% and the schema itself is unusually informative, explicitly distinguishing the real store ids used here from the 0-3 reference-catalog ids accepted by arbys_menu's store_id. The description adds no parameter detail beyond what the schema already states, so baseline 3 applies.

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: fetching one Arby's restaurant by store id. It also names the sibling arbys_locations as the source of valid ids, which helps disambiguate from arbys_directory/arbys_menu, though it doesn't differentiate from those 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 parenthetical 'e.g. one found via arbys_locations' implies the intended workflow (get an id from the list tool, then fetch the detail), but there is no explicit when-to-use statement, no exclusions, and no mention of what to do without a known id.

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