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

Adds auth/role requirements, default and max days, and behavior when class_id is omitted (worst-first rollup). Annotations already indicate read-only and idempotent, so description adds valuable context.

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?

Two sentences, front-loaded with constraints, no redundant information. Every word adds value.

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?

Covers auth, role, time window, and usage with/without class_id. No output schema, so return values not required. Adequate for a retrieval tool with good annotations.

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 covers both parameters with descriptions; description adds meaningful context for class_id (behavior when omitted) and reaffirms defaults for days. No contradictions.

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 clearly states 'Aggregate class-level trends across the tutor's classes' with specific time window and optional class_id. It distinguishes from sibling 'get_session_trends' by specifying class-level aggregation and auth role.

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?

Explicitly states 'Auth-only. Tutor-only.' and provides guidance on when to pass class_id vs omit it to get a rollup. No explicit alternatives listed, but context is clear.

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