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

Annotations already declare readOnly=false, idempotent=true, destructive=false, but the description adds substantial context beyond them: the admin-role gate (same as patch drafting/publishing), the fact that this initiates recurring unattended email delivery, and that the operation is free with no provider call or credit spend. That is exactly the kind of side-effect and cost disclosure annotations cannot carry.

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 dense sentences, front-loaded with the replacement scope, then prerequisites, then cost. No filler and no repetition of schema or annotation content for its own sake.

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 write tool with no output schema and safety fully covered by annotations, the description supplies the remaining essentials: auth gate, side effect (recurring email), cost profile, and full-replace semantics. Nothing an agent needs to call it correctly appears to be 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 earns an extra point by clarifying replacement semantics — the recipient array and interval are submitted as a whole and overwrite rather than merge, which an agent needs to know when forming the payload. It adds no per-field syntax beyond the 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?

States a specific verb (creates or replaces) and resource (a report definition's schedule) and immediately scopes it: the whole interval + recipient list, not individual fields. That distinguishes it from sibling tools like create_report_definition, set_report_widgets, and delete_report_schedule without the agent 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?

Gives clear context: use it to set the entire schedule, it requires admin role, and it starts unattended recurring email delivery. It does not explicitly name alternative tools (e.g. delete_report_schedule for removal, or how to edit a single field) or state when-not-to-use, so it stops short of a 5.

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