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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds genuine behavioral context by stating the fallback: it returns the default Free plan when none is active, which an agent would not infer from annotations or schema.

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 sentences, no waste, and the usage trigger is front-loaded before the return description and the exclusion. Every clause earns its place.

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?

An output schema exists so return values need not be enumerated, and the annotations cover the safety/idempotency profile. The description supplies the remaining missing piece (the Free-plan fallback), making the definition complete for a single-parameter read 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 is one parameter with 100% schema description coverage, including a hex pattern, so the schema fully documents it. The description adds no extra meaning about clinicId beyond what the schema provides, which is the expected baseline-3 case when structured data already carries the load.

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?

Specific verb+resource: retrieves a practice's DoctoFam plan, its status, billing frequency and plan caps. It also explicitly carves out sibling territory ('Not for invoices or amounts billed'), so the agent can distinguish it from billing-related tools without opening any 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?

Strong when-to-use triggers are given ('when someone asks which plan a practice is on, whether it is active, or how many appointments, patients, rooms or users it allows'), plus one exclusion for invoices. It does not name a specific alternative tool for the billing case, so it stops short of full routing guidance.

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