add_class_students

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

With no annotations, the description must carry the full behavioral burden. It does so by stating the permission requirement ('Requires PS_ENABLE_WRITES'), the concurrency constraint ('Never call ... in parallel ... use one call at a time'), and the side-effect guarantees ('without disturbing the students already in the class or their other classes'). It also notes idempotency, which is crucial for safe re-invocation.

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 moderately long but well-structured with a safety header, behavior explanation, usage example, and arg list. Every section serves a purpose, and the safety warning is front-loaded. It is not bloated; the extra length is justified by the complexity of the write operation.

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?

The description covers the tool's function, permission needs, idempotency, concurrency constraints, and parameter sourcing. Given the operation's complexity and the presence of an output schema (which presumably documents return values), this is nearly complete. It might note failure modes, but that is a minor omission.

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 0%, so the description must add meaning. It provides explicit arg descriptions: 'section_id: Class/section ID (from list_classes)' and 'student_ids: One or more student IDs (from list_students)'. This goes beyond the schema's type/title and tells the agent exactly where to obtain valid inputs, which is high-value guidance.

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 opens with 'Enroll students in a class,' a specific verb plus resource that clearly distinguishes it from siblings like list_class_students or remove_class_students. It avoids tautology and names the operation precisely.

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?

The description gives a concrete use case: 'To assign a whole grade at the start of the year, call this once per classroom with that classroom's students.' It also explains idempotency ('Students already enrolled are skipped, so re-running is safe') and warns about parallel calls. It does not explicitly mention alternatives, but the context is sufficient for an agent to decide when to use it.

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