MinIO MCP Server

minio_list_objects

List files and directories in a MinIO bucket to manage object storage content. Filter by prefix or list recursively for organized access.

Instructions

List objects in a MinIO bucket

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "bucket_name": "<bucket_name>"
    },
    "name": "minio_list_objects"
  }
}

Input Schema

Name	Required	Description
`bucket_name`	Yes	Name of the bucket
`prefix`	No	Filter objects by prefix (optional)
`recursive`	No	List objects recursively (default: false)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Mar 9, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations provided, the description carries full burden for behavioral disclosure but offers minimal information. It doesn't mention whether this is a read-only operation, what permissions are required, how results are returned (e.g., pagination, format), or any rate limits. This leaves significant gaps for an agent to understand the tool's behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that communicates the core purpose without any wasted words. It's appropriately sized for a straightforward list operation and gets directly to the point.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 3 parameters, no annotations, and no output schema, the description is inadequate. It doesn't explain what the output looks like (e.g., list of object names, metadata), how errors are handled, or any behavioral nuances. The agent would struggle to use this effectively without trial and error.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds no parameter information beyond what's already in the schema, which has 100% coverage with clear descriptions for all three parameters. This meets the baseline score of 3 when schema coverage is high, but doesn't provide additional context like examples or edge cases.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('List objects') and target resource ('in a MinIO bucket'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'minio_list_buckets' or 'minio_stat_object', which prevents a perfect score.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives like 'minio_list_buckets' (for listing buckets instead of objects) or 'minio_stat_object' (for detailed info on a single object). The description only states what it does, not when it's appropriate.

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

Deploy Server