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

Despite annotations already flagging destructiveHint=true, the description adds rich behavior beyond them: per-learner partial-failure semantics, that an unexpected server error aborts the batch with no per-learner results but prior enrollments persist, that already-enrolled learners keep enrollment with created:false while invites are re-sent and sign-in links replaced, and that a full-failure batch errors. This is substantial disclosure well beyond the structured fields.

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?

It is a single dense paragraph but well front-loaded: purpose first, then the sibling alternative, then failure/retry behavior, then return shape. Every clause carries operational meaning, though the length pushes the limit of tightness.

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 no output schema, the description fully explains the return value ('Enrolled N, failed M' plus per-learner fields and the all-failed error case), and it covers idempotency, retry safety, and prerequisite behavior. Nothing an agent needs to call it correctly is missing.

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%, so the baseline is 3, but the description adds cross-parameter meaning not in the schema: that sendInvite suppresses email unless true, that it overrides issueMagicLink, and that emails/learners follow the same account-creation and prerequisite rules as enrollment_create. This is genuine added value on top of a fully documented schema.

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+resource+scope ('Enroll up to 100 learners in one course in a single call') and explicitly contrasts itself with the sibling enrollment_create, naming the exact conditions that select the other tool (one learner, redirectTo, externalReference). An agent can differentiate it from enrollment_create without opening any 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?

It gives explicit when-to-use-this vs when-to-use-the-alternative guidance: 'use enrollment_create for one learner or to pass redirectTo or externalReference.' It also notes the cap of 100 and the course-id source (course_list), 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.