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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered by structured data. The description adds nothing behavioral beyond that: no note on how it handles unreachable targets, invalid exam counts, or rounding, and the templated 'Returns: {error}' line conveys no real information.

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?

The description is short and leads with the core purpose, which is good. However, the second sentence is boilerplate: the 'Returns: {error}' placeholder is an unsubstituted template token, and the list_bundles cross-reference does little work here, so not every sentence earns 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 simple read-only calculator with a full parameter schema and an output schema, the description is close to adequate, but it leaves real gaps: it never states the expected unit convention (the schema's 0-20 bounds imply a French-style scale), and the placeholder return line adds confusion rather than clarity. An agent would still have to infer the grade-scale context from the schema alone.

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 100% with all four parameters documented in the schema, including the 0-20 range for averages and the exclusive minimum on exam counts. The description adds no syntax, ordering, or validation semantics beyond what the schema already states, so the baseline of 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: computes the score required on remaining exams to hit a target average. That is distinguishable from generic siblings like calculate_grade_average or calculate_average, though the description never explicitly names the neighboring grade/GPA calculators it could be confused with.

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?

There is no when-to-use or when-not-to-use guidance, and no naming of alternatives such as calculate_grade_average or calculate_gpa_french. The only routing hint, 'See list_bundles for related education calculators', is a discovery pointer, not a criterion for selecting this tool over a sibling.

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