AWS MCP Server

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

Annotations already indicate destructiveHint=true and idempotentHint=true, which cover key behavioral traits. The description adds minimal context beyond this, such as the region scope, but doesn't detail consequences (e.g., data loss, billing implications) or rate limits. No contradiction with annotations.

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, front-loaded with the core action, and no wasted words. It efficiently conveys the essential purpose without redundancy or fluff.

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?

For a destructive tool with no output schema and moderate schema coverage, the description is minimal. It covers the basic action but lacks details on outcomes, error handling, or integration with sibling tools, leaving gaps in contextual understanding.

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 50%, with 'region' and 'DryRun' documented but 'InstanceIds' lacking a description in the schema. The description doesn't add parameter details beyond implying region usage, so it partially compensates but leaves 'InstanceIds' semantics unclear. Baseline 3 is appropriate given the mixed coverage.

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 clearly states the action ('terminate') and resource ('EC2 instance'), with the region constraint adding specificity. It distinguishes from siblings like 'stop-ec2-instance' or 'delete-*' tools by specifying termination, though it doesn't explicitly contrast with them.

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 guidance on when to use this tool versus alternatives like 'stop-ec2-instance' or 'delete-*' tools for other resources. The description mentions the region but doesn't provide context about prerequisites, permissions, or typical workflows.

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