s3_list_bucketsList all S3 buckets accessible with your configured credentials, so you can discover available object storage before managing, reading, or inspecting objects.
List all available S3 buckets visible to the configured credentials.
| 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?
Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds meaningful context beyond that: results are limited to buckets visible to the configured credentials, which tells the agent why the list may be partial.
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?
A single front-loaded sentence with no filler; the resource and its scoping constraint are both stated immediately.
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 tool with full annotation coverage and no output schema, the description is nearly sufficient. It does not state what the response contains (e.g., bucket names) or whether large accounts are truncated, a minor gap.
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 takes zero parameters, so per the baseline this scores 4. The empty schema and the description agree that no filtering or paging inputs are accepted.
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?
States a specific verb (List) and resource (S3 buckets) with scope ('visible to the configured credentials'). The bucket-level resource naturally distinguishes it from the object-level siblings such as s3_list_objects and s3_head_object.
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?
No explicit when-to-use statement, no exclusions, and no named alternatives. Usage is implied by the resource scope — an agent would reasonably call this to discover buckets before listing objects — but the description never says so.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.