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

With readOnlyHint and openWorldHint already declared, the description adds useful context beyond annotations: the exact return shape (id value + name label) and the underlying GET endpoint. It does not cover auth, rate limits, or pagination, but for a simple read-only list it adds meaningful operational detail.

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 tightly packed sentences with zero waste: purpose and output first, then the key usage insight, then the endpoint. The most important routing advice is front-loaded and easy to scan.

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 parameterless list tool with no output schema, the description supplies the missing return shape, the endpoint, and the integration role ('most other tools take a location_id'). An agent has everything needed to call it and use its result correctly.

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 has zero parameters, so the baseline is 4. The description adds no parameter semantics because none exist, but it does clarify the output mapping of id and name, which helps the agent use the result.

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 (List) and resource (locations/facilities of this Gingr app) and specifies the returned shape (id as value, name as label). It also positions the tool relative to its siblings as the prerequisite call for any tool needing a location_id, so an agent can identify it without opening the 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?

The phrase 'Good first call: most other tools take a location_id' gives clear usage context and a strong routing signal to call this before other operations. It lacks explicit when-not-to-use guidance and does not name specific alternatives, keeping it short of 5.

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