AWS MCP Server

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

With no annotations provided, the description carries the full burden. It successfully discloses the default scope behavior (customer-managed only), but omits other key behavioral traits like pagination/truncation behavior, rate limiting, or explicit read-only safety confirmation.

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 tightly constructed sentences with zero waste. The first establishes purpose; the second immediately addresses the most important parameter (scope) and its default value. Well front-loaded.

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?

Adequate for a straightforward list operation with four parameters and no output schema. Covers the essential functionality and the key behavioral quirk (default scope). Could be improved with pagination/truncation notes but complete enough for correct invocation.

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?

Input schema has 100% description coverage, establishing a baseline of 3. The description adds semantic clarity by mapping 'Local' to 'customer-managed' and explaining the default behavior, though it largely restates schema information.

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?

Clearly states the specific action (List) and resource (IAM policies), including the critical behavioral detail that it defaults to customer-managed only. Does not explicitly differentiate from sibling IAM list tools (aws_iam_list_roles, aws_iam_list_users), though the resource type is distinct.

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?

Provides clear context for the tool's primary filtering dimension by explaining the three scope options (default 'Local'/'AWS'/'All') and when to use each. Lacks explicit comparison to alternative tools, but the scope guidance effectively constrains appropriate usage.

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