Lists every collection in the connected MongoDB database, providing a clear overview of existing data stores to help select targets for queries, counts, or aggregations.
List all collections in the database
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly conveys a read-only enumeration behavior with no visible side effects. It does not mention edge cases like system collections or exact return shape, but for such a simple operation the core behavior is transparent.
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, clear sentence with no filler or redundant wording. Every word contributes meaning, and the key information is front-loaded.
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 zero-parameter read-only listing tool, the description is largely complete: it states the action, the resource, and the scope. The only minor gap is that it does not specify the return format, though 'list all collections' conventionally implies a list of collection names.
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 tool has zero parameters, so there is nothing for the description to add beyond what the empty schema conveys. This matches the baseline of 4 for parameter-less tools.
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 uses a specific verb ('List') and resource ('collections') with a clear scope ('all in the database'). It also differentiates from sibling tools like find, count, and aggregate, which operate on documents inside collections rather than enumerating collections themselves.
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 implies the tool is for database-level enumeration rather than document-level operations, but it does not explicitly state when to use it over the sibling tools. There is no mention of alternatives or conditions that would select a different tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.