AWS MCP Server

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

No annotations provided, so description carries full burden. It successfully discloses return attributes (size, throughput mode, lifecycle state), but omits behavioral details like pagination behavior (despite max_items parameter), cost/performance implications of listing all EFS systems, or error conditions.

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?

Single 9-word sentence with action verb front-loaded. Every word earns its place: identifies resource type and specific return attributes without redundancy.

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?

With 100% schema coverage and explicit mention of return attributes (compensating for missing output schema), description is adequate for tool selection. Minor gap: lacks pagination behavior explanation despite max_items parameter.

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 has 100% coverage with clear descriptions for all 4 parameters (profile, region, file_system_id, max_items). Description adds no parameter-specific semantics beyond the schema, earning baseline 3.

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?

Description uses specific verb 'List' with explicit resource 'EFS file systems' and distinguishes from siblings (e.g., aws_efs_describe_access_points, aws_efs_describe_mount_targets) by clearly targeting file systems specifically rather than access points or mount targets.

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?

Provides no guidance on when to use the file_system_id filter versus returning all systems, nor when to prefer this over sibling EFS tools like aws_efs_describe_access_points. No mention of use cases or prerequisites.

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