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

Annotations already cover read-only, idempotent, closed-world safety. The description adds genuinely useful business context: prices only exist for certain plan/medication combinations (naltrexone has quarterly and annual, varenicline only quarterly), which prevents the agent from promising an annual varenicline plan. Return structure is described conceptually rather than field-by-field.

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?

Two dense sentences, front-loaded with what is returned and immediately qualified by the per-medication plan structure. No filler or restatement of the title.

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-enum-parameter read with no output schema, the description effectively supplies the return shape (one-time assessment fee plus per-plan prices) and the variation across medications. Nothing an agent needs to call or interpret this correctly is missing.

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 coverage is 100% with an enum and per-value descriptions, so the baseline is 3. The description earns an extra point by mapping each enum value to the specific plans available, giving the agent meaning the schema doesn't carry.

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: returns treatment costs, including the $20 assessment fee and per-plan prices. The subject matter is clearly distinct from the siblings (check_state, get_medication_info, get_start_link), though it never names them 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?

Usage is only implied — an agent infers it should call this when a user asks about cost. There is no explicit when-to-use/when-not-to-use statement and no pointer to alternatives for related questions like medication details or eligibility.

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