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

Annotations declare idempotentHint=true and destructiveHint=false, but the description goes further by explaining the mechanism that makes retries safe (caller-generated itemIds reused on retry) and the exact error-recovery path for version conflicts. It also discloses the 100-item ceiling, none of which is in 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?

The what, the idempotency contract, the limits, and the failure-handling rule are packed into five tight sentences with the primary action front-loaded and no filler.

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 mutation tool with no output schema, it covers the essentials an agent needs: batch limits, version preconditioning, retry safety, and error recovery. Nothing required 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% and the schema already documents itemId reuse semantics, listId provenance, and expectedVersion opaque format. The description's guidance on where to obtain listId/expectedVersion and the 'in order' constraint largely restates what the schema already says, so it earns baseline rather than added value.

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 (add), resource (several items), and scope (an owned Library List, in one call, in order) that an agent can act on directly. It also excludes trip checklists, which cleanly separates it from the many checklist_* and library_list_item_* siblings.

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 prescribes the workflow: fetch listId and expectedVersion from library_list_get, split lists over 100 items, and handle library_version_mismatch by re-reading rather than blindly retrying. It also names the boundary case (Library Lists, not trip checklists), 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.