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 upsert nature ('Create or update') and the runtime constraint ('Blocked in --readonly mode'). Missing details on permissions requirements, versioning behavior, or return values.

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 sentences, zero waste. Front-loaded with the core action, followed by operational constraint. Every word earns its place.

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 but minimal for a 7-parameter mutation tool with no output schema. Relies heavily on the complete input schema. Could benefit from mentioning success indicators, parameter versioning implications, or AWS credentials requirements.

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 100% schema description coverage, the structured schema fully documents all 7 parameters. The description adds no explicit parameter semantics beyond what the schema provides, earning the baseline score for high-coverage schemas.

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?

Clear verb-resource combination ('Create or update an SSM parameter') that accurately describes the upsert operation. Distinguishes reasonably from read-focused siblings (aws_ssm_get_parameter, aws_ssm_describe_parameters) through the write verbs, though it doesn't explicitly reference 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?

Provides critical environmental constraint ('Blocked in --readonly mode') telling agents when the tool will fail. However, lacks explicit guidance on when to use this vs. read-only alternatives or AWS Secrets Manager for sensitive data.

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