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

The readOnlyHint annotation already declares this is a safe read operation. The description adds useful behavioral context beyond that: it is scoped to agencies accessible by the API key and returns UIDs, currency, and default check-in/out times. It does not cover pagination or rate limits, so it falls short of the highest transparency tier.

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?

The description is only three short sentences, front-loads the purpose, then the usage cue, then the endpoint. Every sentence earns its place with no redundant or vague phrasing.

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 zero-parameter, read-only list tool with no output schema, the description provides enough context: it states access scope, returned fields, and when to call it. There is no output schema to require explanation, and no missing behavioral detail that would prevent correct invocation.

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 description has no parameter semantics to explain. Per the baseline for zero-parameter tools, this dimension is naturally well-covered without additional text.

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 states a specific verb and resource ('List the agencies'), names the scope ('this API key can access'), and enumerates returned fields including UIDs and check-in/out times. It is easily distinguishable from sibling list tools, which cover guests, jobs, messages, orders, owners, properties, reviews, services, and threads.

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 gives clear usage context: 'Start here to find the agency_uid other tools need.' This tells the agent when to call it relative to other tools. It does not include explicit when-not conditions or name alternatives, but no sibling tool lists agencies, so the guidance is strong without being exhaustive.

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