AWS MCP Server

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

No annotations are provided, so the description carries the full burden of disclosure. It lists example target types (Lambda, SQS) but fails to disclose safety characteristics (read-only vs destructive), pagination behavior, or error handling when rules don't exist.

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 with zero waste. Front-loaded with action verb and key nouns. Every word earns its place by conveying the exact operation and resource type.

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 100% schema coverage and the straightforward nature of the operation, the description is minimally viable. However, with no output schema or annotations, it could improve by indicating what information is returned about targets (ARNs? configuration?) or mentioning pagination limits.

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% with clear parameter descriptions. The description adds valuable semantic context by clarifying this is specifically for 'EventBridge' rules and giving examples of target types (Lambda, SQS) that help interpret the 'rule' parameter's domain.

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 uses a specific verb (List) with clear resource (targets) and scope (attached to an EventBridge rule). It effectively distinguishes from siblings like aws_events_list_rules (lists rules) and aws_events_describe_rule (describes rule configuration) by explicitly focusing on '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?

No explicit when-to-use guidance or alternative tools are mentioned. While the name implies usage context, the description does not state prerequisites (e.g., needing the rule name first) or distinguish when to use this versus describe_rule if targets are included there.

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