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

Annotations already cover read-only, idempotent and open-world. The description adds two things annotations can't: the local-time basis for "not started" and an explicit call budget (one cached site lookup, then 1 per 200 classes, capped at 11). The API-cost disclosure is a strong addition for an open-world tool.

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 with the returned content front-loaded before alternatives and cost. No filler. The headline phrase is slightly cryptic and has to be decoded by the clause that follows, which costs a little immediate clarity.

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?

There is no output schema, so the description carries the burden of saying what comes back, and it does so by naming all three lists. Combined with the call-budget note and local-time clarification, an agent has everything needed to call this correctly and know what to expect.

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%, so every parameter is already documented, and the baseline applies. The description adds only indirect meaning — that minSpotsLeft feeds the 'open spots' list and that dates are interpreted in studio local time — without covering limit, siteId, or date-window interaction beyond what the schema says.

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 opening line is a bit oblique ("What on a short schedule needs a person"), but the colon-clause enumerates exactly what the tool returns: future classes with open spots, classes with a waitlist, and classes with a substitute teacher. That enumeration distinguishes it from find_classes and class_attendance_summary, which are named.

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 explicitly routes the agent elsewhere: find_classes to browse the schedule or look for open spots, class_attendance_summary for fill rates and busiest times. That is real when-to-use guidance. It doesn't state when-not to call it or any prerequisites, so it stops short of a 5.

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