Add a saved item to a collection. Both the item and collection must already exist.
| Name | Required | Description | Default |
|---|---|---|---|
| reason | No | Why this change was made (shown to user in change history) | |
| item_id | Yes | The item ID to add | |
| collection_id | Yes | The collection ID |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide idempotentHint, destructiveHint, and readOnlyHint, covering the safety profile. The description adds useful behavioral context by stating that the item and collection must already exist, clarifying that this operation does not create new entities. 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 a single, front-loaded sentence with no fluff. Every word contributes to understanding the tool's function and prerequisites.
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 simple mutation tool with no output schema, the description covers the essential context: action and preconditions. It doesn't explain error behavior or return values, but those are not required given the tool's simplicity and existing 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?
The input schema has 100% coverage, with descriptions for all parameters (item_id, collection_id, reason). The description itself does not add parameter-specific information beyond what the schema already provides, so the baseline score of 3 is appropriate.
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 saved item to a collection.' It uses a specific verb and resource, and the requirement that both must already exist distinguishes it from sibling tools like add_item (which creates a new item) and create_collection.
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?
The description gives clear context by stating that both the item and collection must already exist, which serves as a prerequisite and implies when to use the tool (not for creation). It does not explicitly name alternative tools or exclusions, but it is sufficient for this straightforward operation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools have clearly distinct purposes with no obvious duplicates. The only potential overlap is between update_item and update_price, but the descriptions clarify that update_price is specifically for manual price corrections with history tracking.
All tool names follow the snake_case verb_noun pattern consistently (e.g., add_item, create_collection, get_item_graph). Slight deviations like add_to_collection and ping are still predictable and conventional.
With 23 tools, the server sits in the heavy range (16-25). While each tool serves a distinct purpose, the count is higher than typical for a shopping-save app and may feel overwhelming, though not excessive.
The tool surface covers full CRUD for items and collections, relations, history, activity, and utilities. Minor gaps exist—such as no dedicated 'move item between collections' tool—but workarounds are possible using existing tools.
