What If Grade

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

Annotations already declare readOnlyHint=false and destructiveHint=false; the description adds real value beyond them by clarifying the write is visible only to the caller, is not a real grade, is reversible via reset_what_if_grades, and is treated as expensive by Canvas. It stops short of stating whether repeated what-if writes accumulate per submission or expire, which would round out the mutation semantics.

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?

Three sentences, zero waste: outcome first, then the safety caveat, then the alternative routing. Each sentence carries distinct information and the most decision-relevant content is front-loaded.

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 mutation with no output schema, the description covers everything an agent needs: what it returns (recalculated grade), that the write is scoped and non-authoritative, how to reverse it, and when to pick a sibling instead.

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 carry descriptions, so the schema already does the heavy lifting. The description adds only a scope hint ('one assignment'), not format, bounds, or valid ranges for the score value, so 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 chain: enter a hypothetical score on one assignment, receive a recalculated course grade. It also names the mechanism (group weights and drop rules) and explicitly differentiates itself from siblings reset_what_if_grades and compute_needed_score.

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?

Explicit routing is given on both sides: use reset_what_if_grades to undo, and use compute_needed_score instead when you want pure math with no writes. The condition that selects the alternative (only available submission vs. arbitrary math) is spelled out, leaving nothing to inference.

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