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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description still adds substantive context: reads send no messages and confirm no appointments, hidden prices come back as null, starting prices are not firm quotes, durations are not reservations, and returned customer content is untrusted data rather than instructions. Only the prompt-injection caveat alone would be worth the sentence; the data-interpretation caveats make this a genuinely informative definition.

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 payload is front-loaded in the first clause, with caveats and the safety note following in a single dense block. Every sentence carries information, though the 'reads do not change records' clause partially restates the readOnly annotation and the paragraph is long enough that a reader must parse multiple ideas in one breath.

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?

With an output schema present the description need not catalogue return fields, yet it still explains the ambiguous ones (null amounts for hidden prices, starting vs. exact vs. quote). Combined with 100% schema coverage and annotations covering safety, an agent has everything needed to call and interpret this tool.

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%, so limit and cursor are fully documented in the schema (range, default, opaque-token semantics). The description reinforces that results are paginated but adds no syntax or format detail beyond the schema, so the 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?

Names a specific verb and resource ('List active, approved services') and enumerates the payload the agent gets back: descriptions, estimated durations, and USD pricing with its three forms. It is trivially separable from siblings like list_calls and list_requests, which deal with different resources.

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 description implies the use case (browsing the approved service catalog) and gives operating guidance for paging and for interpreting price/duration fields, but it never states when to pick this tool over a sibling or what the caller must already know (e.g. auth or business context). Usage is inferable but not spelled out.

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