Fetch the contents of a list by its ID to inspect items, verify membership, or confirm the list exists before processing.
Retrieves the items in an existing list by its ID.
WHEN TO USE:
To inspect the contents of a list before processing
To verify which items are in a list
To check if a list exists
| Name | Required | Description | Default |
|---|---|---|---|
| list_id | Yes | The list ID returned by create_list. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It implies a read-only operation ('retrieves') but does not explicitly state non-destructiveness, authentication needs, or behavior on missing list IDs. While adequate for a simple get, it lacks depth.
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 very concise: a single sentence followed by three bullet points. All information is front-loaded and every sentence serves a purpose with no wasted words.
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 retrieval tool with one parameter and no output schema, the description is largely complete. It covers purpose and usage context. However, it omits details about return format, error handling, and pagination, which would raise it to a 5.
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 schema already describes the only parameter (list_id) as 'The list ID returned by create_list' with 100% coverage. The description adds no additional meaning beyond the schema, so baseline 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 'Retrieves the items in an existing list by its ID,' specifying the action (retrieves), resource (items in a list), and method (by ID). This distinguishes it from sibling tools like create_list or list_all_lists.
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?
Includes a 'WHEN TO USE' section with three bullet points (inspect contents, verify items, check existence), providing clear context for when the tool is appropriate. However, it does not explicitly state when not to use or mention alternatives, so it falls 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.