add_to_collection

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

The description adds behavioral context beyond annotations by explaining the operation is 'safe, key-preserving reorganization within the same library' and that it adds to existing collection memberships. It also explains the version parameter's role as the 'current version.' Annotations already cover idempotency and non-destructiveness, so the additional context is meaningful but not overly detailed.

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 three sentences, each serving a clear purpose: stating the action, providing usage guidance with an alternative, and defining the version parameter. It is front-loaded and contains no redundant or filler 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?

For a relatively simple tool with annotations and no output schema, the description covers the essential aspects: what it does, when to prefer it over an alternative, and the key nuance of the version parameter. It does not mention return values or prerequisites, but the absence of an output schema and the presence of sibling tools lessen the need. Minor gaps remain, such as behavior if the collection does not exist.

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 description coverage is 0%, so the description must compensate. It explicitly defines 'version' as the item's current version and refers to 'update_item' for more context. However, 'key' and 'collection_key' are not explained, though their meanings are reasonably inferable from the parameter names and tool purpose. This partial compensation warrants a mid-range score.

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 tool's function: 'File an item into a collection, in addition to any it's already in.' It also differentiates it from a sibling by naming 'move_item_to_different_library' and describing this as a safe, same-library reorganization. This gives a specific verb, resource, and scope.

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?

Explicit usage guidance is provided: 'prefer this over move_item_to_different_library whenever the goal is just organizing, not actually relocating to a different library.' This tells the agent when to use this tool and when to consider an alternative. It also implies that for cross-library moves, the alternative should be used.

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