create_item

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

Beyond annotations (destructiveHint=false, readOnlyHint=false), the description adds valuable behavioral details: it is 'safe' because it creates a brand-new key, and it states that invalid fields 'raises an error naming the problem'. This gives the agent confidence about failure modes and side effects. No contradiction with annotations.

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 efficiently organized with an initial clarity sentence followed by a clean parameter-by-parameter breakdown. Every sentence adds value: examples, validation rules, and a pointer to list_collections. No fluff or redundant content.

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?

All five parameters are covered, error behavior is mentioned, and the description references list_collections for key sources. However, it does not state what the tool returns (e.g., the new item key), which could be useful given there is no output schema. Still, for a create operation, the description is largely complete for usage.

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?

Despite schema description coverage being 0%, the description thoroughly explains every parameter with examples: item_type with valid values, fields with a JSON example and dependency on item_type, creators with structure, tags as plain strings, and collections as keys from list_collections. This fully compensates for the schema's lack of descriptions.

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 the action: 'Add a new item to the library' with a specific resource and verb. It further distinguishes itself from update operations by explicitly noting 'never touches an existing one', which differentiates it from sibling tools like update_item or trash_item.

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 provides clear context for when to use the tool (creating a new item) and explicitly says it does not touch existing items, implying you should not use it for updates. However, it does not explicitly name alternative tools or provide exclusions; the guidance is implicit rather than explicit.

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