List EC2 key pairs in a given AWS region to retrieve key_name values for launching instances with aws_run_instances.
List EC2 key pairs registered in the given region. Use the key_name values returned here as the key_name argument to aws_run_instances.
| Name | Required | Description | Default |
|---|---|---|---|
| region | Yes | AWS region (e.g. us-east-1). | |
| account | No | AWS account label to act in; omit for the default account. |
Changes observed during successful MCP inspections.
v2.28.0Input schema / properties / accountAdded value: +{
+ "description": "AWS account label to act in; omit for the default account.",
+ "type": "string"
+}v2.24.0v2.23.8v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It discloses region scoping and the intended chaining use, but says nothing about read-only nature, permission/account requirements beyond the schema's 'account' field, or the shape of returned data.
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?
Two short sentences, zero filler, with the core action stated first and the chaining hint second. Nothing needs trimming.
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 simple two-parameter read tool with no output schema, the description covers purpose and the key downstream use. It is a bit thin on behavioral details (permissions, return contents), which is the only real gap.
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 100%, so both parameters are already documented in the schema. The description adds no syntax or format detail for 'region' or 'account' beyond what the schema provides, so the baseline 3 applies.
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?
States a specific verb and resource ('List EC2 key pairs') and scopes it to the given region. The resource is distinctive enough to separate it from sibling listing tools, but the description never explicitly contrasts itself with alternatives like aws_list_amis or aws_run_instances.
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?
Explicitly tells the agent when to use the result: feed key_name values into aws_run_instances. It gives a clear forward path but offers no when-not-to-use conditions or comparison to other key/credential-related tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.