AWS MCP Server

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

No annotations provided, so description carries full burden. States 'List' implying read-only, but doesn't confirm safety, disclose return format/schema, pagination behavior, or permission requirements. Minimal behavioral disclosure for a read operation.

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 sentence of 9 words. Front-loaded with action and resource. No redundancy or waste. Appropriate density for the tool's scope.

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?

Adequate for a 5-parameter discovery tool with well-documented schema. Covers primary use cases (listing by filesystem or VPC). Could improve by noting that parameters are optional filters or explaining behavior when called without filters (returns all mount targets in account?).

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 coverage is 100%, so baseline applies. Description mentions 'file system or VPC subnet' which conceptually maps to file_system_id and vpc_id parameters, adding context about their relationship. However, doesn't mention mount_target_id parameter for singleton lookups.

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', clear resource 'EFS mount targets', and specifies scope 'for a file system or VPC subnet'. Distinct from sibling aws_efs_describe_file_systems (which returns file system metadata, not mount targets) and aws_efs_describe_access_points.

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?

Implies usage context by mentioning 'for a file system or VPC subnet', indicating it filters by these resources. However, lacks explicit when-to-use guidance, prerequisites (e.g., needing one filter parameter), or alternatives for different query patterns (e.g., querying by mount_target_id).

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