AWS MCP Server

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

Annotations provide readOnlyHint=false (mutation), openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds that this updates descriptions specifically for ingress rules, which is useful context beyond annotations. However, it doesn't mention what happens to existing descriptions not updated, whether this requires specific IAM permissions, or any rate limits.

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?

The description is a single, efficient sentence that gets straight to the point. There's no wasted verbiage, though it could benefit from slightly more detail given the tool's complexity.

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 complex nested parameters (SecurityGroupArgs with multiple sub-properties), 50% schema coverage, no output schema, and no sibling differentiation, the description is inadequate. It doesn't explain what the tool returns, how to identify which rules to update, or the relationship between the two parameter structures.

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?

With schema description coverage at 50% (only 1 of 2 parameters has descriptions in schema), the description fails to compensate. It mentions 'region' and 'security group rule ingress' but doesn't explain the complex SecurityGroupArgs structure, the relationship between GroupId/GroupName, or what IpPermissions/SecurityGroupRuleDescriptions arrays should contain.

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 ('Update the description') and target resource ('security group rule ingress'), making the purpose understandable. However, it doesn't differentiate from its sibling 'update-security-group-rule-descriptions-egress' beyond specifying 'ingress', which is minimal differentiation.

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?

The description provides no guidance on when to use this tool versus alternatives like 'modify-security-group-rules' or the egress version. It mentions 'in the given region' but doesn't explain why region matters or any prerequisites for using this tool.

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