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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so 'Read only' in the description is pure repetition with no added value. What does add value is disclosing that each result carries a price per class and that results are scoped to a single student and month. No mention of pagination, ordering, or what makes a class tab-eligible.

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?

A single front-loaded sentence covering scope and payload, with no filler. The only waste is the trailing 'Read only', which merely echoes the annotations instead of earning 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?

For a two-parameter read-only list tool with a fully documented schema and no output schema, the essentials are present. However, the defining concept — what makes a class eligible to be added to a tab — is never explained, which is the one thing an agent cannot derive from structured fields.

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% and both parameters are documented in the schema, including the YYYY-MM format and the default-to-current-month behavior. The description adds no format or semantics beyond that, so the 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?

The description names a specific verb (list) and a well-scoped resource: classes of one student in a month that are eligible to be added to a tab, including the price per class. This is clearly distinct from list_tabs (tabs themselves) and distinguishable from list_student_classes by the 'can be added to a tab' scoping, though it never names the nearest siblings 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?

The phrase 'can be added to a tab' implies the workflow (call this before populating a tab), but the description never states when to prefer it over list_student_classes, list_tabs, or list_student_sessions, nor does it give prerequisites. Usage is inferable rather than stated.

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