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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false, which is a slightly unusual profile for something called a 'preview'; the description resolves that tension by explaining that it creates a bound confirmation artifact and that nothing is transmitted yet. It also discloses the payload contents (included/excluded counts, point scale). It does not state how long the preview remains valid or what approval requires.

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 short sentences, front-loaded with the action and scope, then the no-side-effect guarantee, then the returned contents. No filler and nothing important buried.

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 an output schema present, return structure need not be explained, and the description still sketches what the preview contains. The remaining gap is the unstated handoff to the confirmation sibling and any preview lifetime/authorship constraints ('owner-bound' is asserted but not elaborated).

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% and the single sessionId parameter already carries its own description pointing to list_grading_sessions/create_grading_session; the description adds no syntax, format, or constraint detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 (creates) and resource (an owner-bound confirmation preview for exporting grading-session scores to the source Google Classroom assignment), and implicitly contrasts with the confirm_push_grades_to_google_classroom sibling by labeling itself a preview. An agent can tell this apart from the actual send operation without opening a schema.

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?

"No grades are sent until approved preview execution" clearly frames this as the pre-approval step, giving the agent the usage context. It stops short of naming the confirm_push_grades_to_google_classroom sibling as the explicit follow-up, so routing is inferred rather than stated.

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