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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnly=false, so the mutation profile is covered externally. The description adds genuinely useful context by disclosing that the rubric is regenerated from the type's AP rubric and point total, and that the previous prompt is returned for restoration. It never states what existing rubric/scoring data is discarded, so the destructive consequence remains under-explained.

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 tight sentences with the action front-loaded, followed by the effect and then the return value. No filler, and each sentence contributes a distinct fact.

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 nesting-heavy mutation tool, the description covers purpose, timing precondition, side effect and return. With an output schema present it rightly does not enumerate return fields, and the only real gap is silence on what happens to already-existing rubric data.

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 low (33%), so the description carries more burden. It clarifies the two prompt modes (a Fiveable question versus a teacher-provided prompt) and the role of the AP question type, which maps onto prompt/text, frqType and fiveableQuestionId. It adds nothing for sessionId or the nested images array, so it only partially compensates.

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 states a specific verb (Changes) and a precise resource: a session's question/teacher prompt and AP question type, plus the follow-on effect of regenerating the rubric. It is clearly distinguishable from read-only siblings like get_grading_rubric, though it never names the alternatives it competes with (e.g. update_assignment_draft).

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?

"before any essay is scored" gives a concrete timing precondition that tells the agent when this tool is applicable, which is more than mere implied usage. It stops short of naming exclusions or the alternative tools to use once scoring has begun, so it lands at clear-context-but-no-exclusions.

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