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

With no annotations, the description carries the full burden and does disclose the key side effect: it writes a lead into Pool Founder, and a duplicate is created if a booking already happened via the webhook. That is a genuinely valuable behavioral hazard. It does not mention permission/auth requirements or what the response contains, so it stops short of a 5.

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 sentences, no filler. The positive scope comes first and the critical 'do not call before book_appointment' warning is front-loaded in the second sentence where it will be read.

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 six-parameter mutation tool with no annotations and no output schema, the description covers purpose, correct sequencing, and the duplicate-lead side effect. It omits return-value expectations and permission needs, but those are minor relative to the sequencing guidance it provides.

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% (all six parameters are documented, including examples for 'service'), so the schema already does the heavy lifting. The description adds no formatting, validation, or optionality guidance beyond it, which is the baseline 3 case.

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 names a specific verb and resource ('Create a Pool Pro Florida service lead in Pool Founder') plus the qualifying condition ('customer is interested in service but is not yet booking an appointment'). That condition alone lets an agent distinguish it from book_appointment without opening either 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?

It gives an explicit prohibition ('Do not call this before book_appointment for the same inquiry') and the underlying reason (the Cal.com booking webhook already creates the lead), which is exactly the routing information an agent needs. The alternative tool is named, so there is no inference required.

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