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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds genuine business context beyond that: plan tiers and discount rates, six-month validity, upfront payment, and the separate pricing of in-person Kakkanad clinic sessions. It does not describe the response shape, but the annotations carry most of the remaining burden.

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?

Front-loaded with purpose, then the call-ordering rule, then the plan economics — a sensible information hierarchy with no filler. The plan-detail sentence is dense but earns its place by pre-empting follow-up questions about discount tiers and validity.

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 no input schema, no output schema and rich annotations, the description is the only source of return-content information, and it delivers: session types, prices, plan structures and a pricing exception. Only the exact response envelope is unspecified, which is a minor gap for a zero-parameter catalog 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?

There are zero input parameters, so there is nothing to document in the schema and the baseline is 4. The description does useful work by naming the output fields the agent will need downstream (session_type, plan_code), bridging into the booking call.

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 ("List session types, prices and plans") plus the domain (booking therapy with ElloMind), which cleanly separates it from the booking-mutation siblings. An agent immediately knows this is the read-only reference catalog tool.

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?

"Call before creating a booking so you use a valid session_type and plan_code" gives an explicit sequencing precondition tied to a named sibling workflow. It stops short of naming the sibling tool (create_booking_draft) or stating when not to call it, but the usage context is unambiguous.

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