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 disclosure burden for this mutation operation. It successfully communicates the critical safety constraint (--readonly mode), but omits other behavioral details such as rate limits, delivery idempotency, synchronous vs asynchronous behavior, or cost implications that would aid an agent in invoking the tool safely.

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 consists of two efficient sentences totaling nine words. The first sentence front-loads the core purpose, while the second conveys a critical runtime constraint. No redundancy or filler content is present.

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?

Given the complete parameter schema (100% coverage) and straightforward purpose, the description is minimally adequate. However, for a mutation operation with no output schema and no annotations, it lacks completeness regarding error handling, return values, or AWS-specific constraints (e.g., sending limits, identity verification prerequisites).

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 (profile, region, source, etc. are all well-documented in the schema). The description adds no specific parameter semantics beyond the schema, which aligns with the baseline score of 3 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?

The description uses a specific verb 'Send' with clear resource 'email' and context 'via SES'. It effectively distinguishes this from sibling SES tools (aws_ses_get_*, aws_ses_list_*) which are read-only operations, making it immediately clear this is the action tool for sending.

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 one explicit constraint ('Blocked in --readonly mode'), indicating when the tool cannot be used. However, it offers no guidance on when to prefer this over similar messaging tools like aws_sns_publish or aws_sqs_send_message, nor does it mention prerequisites like AWS credentials or SES verification requirements.

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