aws-s3-connector-mcp

list_objects

List objects in an S3 bucket with file name, size, last modified date, and presigned URL. Filter by prefix or limit results.

Instructions

List all objects in the connected S3 bucket. Returns each object's file name, size, last modified date, and a presigned URL. Optionally filter by prefix (folder path) or limit the number of results.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_objects"
  }
}

Input Schema

Name	Required	Description
`prefix`	No	Filter by prefix/folder path (e.g. 'data/' or 'reports/2026/').
`bucket_name`	No	Override the connected bucket name (optional).
`max_results`	No	Maximum number of objects to return (default: 100).

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 1, 2026

TDQS

A4/5.0

Behavior3/5

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

No annotations provided, so description must disclose behavioral traits. It implies a prior connection ('connected S3 bucket') and is read-only, but does not explicitly state safety or any side effects. This is adequate but not thorough.

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?

Two sentences, no wasted words, front-loaded with action and result. Efficient and clear.

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

Completeness4/5

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

No output schema, but description lists return fields. Lacks details on ordering, pagination beyond max_results, and root behavior. Sufficient for a simple list tool but could be more complete.

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?

Schema coverage is 100% (all parameters have descriptions). The description adds minimal extra context (e.g., 'folder path' for prefix). No significant added value beyond the schema.

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

Purpose5/5

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

Description clearly states 'List all objects in the connected S3 bucket' and specifies return fields (name, size, date, presigned URL). It is distinct from siblings like connect_s3, read_object, and upload_object.

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

Usage Guidelines4/5

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

While no explicit when-to-use or alternatives are mentioned, the purpose is clear. The context of sibling tools makes usage self-evident: use this to browse objects, not to connect, read a single object, or upload.

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

Deploy Server