AWS MCP Server

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

Annotations provide readOnlyHint=false (correct for a mutation), idempotentHint=true (reboots are idempotent), and destructiveHint=false (reboot preserves data). The description adds the regional context but doesn't explain what 'reboot' means operationally (e.g., temporary interruption vs. data loss, instance state transitions). No rate limits, authentication needs, or error conditions are described.

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, zero waste. Front-loaded with the core action. Every word earns its place with no redundant information or unnecessary elaboration.

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 mutation tool with no output schema and incomplete parameter documentation, the description is inadequate. It doesn't explain what happens during reboot, expected response format, error conditions, or permissions needed. The annotations help but don't compensate for missing operational context.

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% (region has description, Ec2Args object doesn't). The description mentions 'region' but doesn't explain its role beyond 'given region'. It doesn't clarify InstanceIds format or DryRun purpose. With medium schema coverage, the description adds minimal value beyond what's already documented in the schema.

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 ('Reboot') and resource ('EC2 instance'), and specifies the region context. It distinguishes from siblings like start-ec2-instance and stop-ec2-instance by focusing on reboot, but doesn't explicitly contrast with terminate-ec2-instance which is more destructive.

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 terminate-ec2-instance. The description mentions region but doesn't explain when region parameter is necessary versus using defaults. No prerequisites or permissions requirements are mentioned.

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