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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is covered. The description adds no further behavioral context (e.g., that it is a pure stateless computation returning a required score, or edge cases like unreachable targets), so it merely meets the lower bar set by 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?

Two tight sentences with a leading worked example that conveys the calculation immediately. The trailing 'Web page: https://calcbright.com/grade-calculator' link does not help an agent invoke the tool and is mild promotional filler.

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?

With 100% schema coverage, three optional defaulted parameters, and readOnly/idempotent annotations, the definition covers what the agent needs. Since no output schema exists, the phrase 'see the score you need' adequately signals the return value, though it does not clarify formatting or failure cases.

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 all three parameters carry their own descriptions, so the baseline would be 3. The description adds real meaning beyond the schema by demonstrating how current, weight, and target combine into the output ('At 88% with a final worth 25%, you need 96%'), clarifying the relationship between inputs.

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 ('see the score you need' on the final), with a concrete worked example (88%, 25% weight, 96% needed). It is distinguishable from gpa_calculator in inferring the goal is a required final-exam score rather than a GPA, though no sibling is named 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?

Usage context is only implied through the example scenario; there is no explicit 'use this when...' statement, no prerequisites, and no pointer to the closely related gpa_calculator to help an agent choose between them.

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