Attendance frequency

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds behavior beyond that: ratios are bounded 0-1 and are null when undefined, and totals are aggregated per semester and year rather than per lesson. It doesn't discuss pagination or account scoping, but the output schema covers return shape.

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, the core behavior and output fields front-loaded, with the sibling routing sentence last. No filler and nothing duplicated from structured fields beyond brief field naming.

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?

Single-parameter read tool with an output schema and annotations already in place; the description supplies the aggregation scope, ratio semantics, and the alternative route. Nothing an agent needs in order to call it 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?

There is a single required parameter (account_alias) whose schema description (100% coverage) already says 'Login alias from list_accounts.' The description adds nothing about that parameter, so the schema does all the work and baseline 3 applies.

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 ('Get attendance totals') plus the exact scope (each semester and the year) and enumerates the returned measures (attended, total, excluded, unknown lessons). It explicitly names the sibling get_subject_frequency as the different case, so the agent can tell the two apart without opening a 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?

The final sentence gives explicit routing: use get_subject_frequency for a per-subject breakdown. However, it does not distinguish this aggregated-frequency tool from the many related attendance siblings (get_attendance, get_attendance_window, get_attendance_detail), so some ambiguity remains.

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