List S3 objects under a bucket or prefix, returning up to 1000 keys per page with continuation tokens for pagination.
List a scoped prefix, at most 1000 objects per page.
| Name | Required | Description | Default |
|---|---|---|---|
| bucket | Yes | ||
| prefix | No | ||
| max_keys | No | ||
| continuation_token | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses a page limit of 1000 objects and implies pagination, but doesn't explain that continuation_token is used for pagination, what happens when no prefix is given, or any permissions or rate limits. This is insufficient for a tool with four parameters.
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 sentence with no wasted words, though it could benefit from being more front-loaded with essential information about pagination.
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?
Given four parameters, no annotations, and no output schema, the description is too sparse. It fails to explain pagination, the role of continuation_token, or how to correctly scope the listing, leaving an agent likely to misuse the tool.
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?
Schema description coverage is 0%, so the description must compensate. It only mentions 'scoped prefix' and '1000 objects per page', which loosely maps to prefix and max_keys, but provides no meaning for bucket or continuation_token, leaving critical parameters undocumented.
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 states the operation (list) and the resource (objects under a scoped prefix), and mentions a page limit of 1000. However, it doesn't clearly distinguish itself from sibling list tools like s3_list_object_versions or s3_list_parts, and lacks explicit S3 context.
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?
There is no guidance on when to use this tool versus alternatives such as s3_prefix_usage or s3_largest_objects. The mention of a 'scoped prefix' implies usage but doesn't specify when or why to choose this over other listing methods.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.