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

Annotations already declare read-only, idempotent, non-destructive behavior. The description adds meaningful calculation behavior: the exact grade mapping, optional honors/AP bonuses for passing grades, and a caveat that school conventions vary. This goes beyond the safety profile in annotations.

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 with no wasted words. It packs the core formula, bonus rules, and caveat efficiently.

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?

Given the low complexity, existing output schema, and rich annotations, the description is nearly complete for calling the tool correctly. The main gap is the absence of explicit usage guidance or sibling differentiation, which is minor for a simple calculator.

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 description coverage is 50%, so the description must add meaning. It contributes the bonus values for honors and AP levels (+0.5 / +1.0) and clarifies that credit weighting is used, which are not fully documented in the schema's level or top-level parameters. It partially repeats the grade scale already detailed in the schema.

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 (computes) and resource (credit-weighted GPA), and includes the base scale and bonus conventions. It is clear what the tool does, but it does not distinguish itself from likely siblings such as grade_calculator or average_calculator.

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 description offers no guidance on when to use this tool versus alternatives, nor any exclusions or prerequisites. Usage is only implied by the tool name and purpose statement.

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