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. It successfully communicates the write-operation nature via the readonly mode constraint, but omits other critical behavioral details such as fan-out delivery semantics, message durability guarantees, retry behavior, or what constitutes a successful return value.

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 exactly two sentences with zero wasted words. The first sentence establishes purpose immediately; the second sentence provides the critical environmental constraint. Every word earns its place in guiding agent selection.

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 this is a 5-parameter write operation with no output schema and no annotations, the description meets minimum viability by stating core purpose and the readonly constraint. However, for a destructive/operational tool, it should ideally disclose success indicators, potential errors (e.g., topic not found), or delivery semantics to be fully complete.

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%, establishing a baseline of 3. The description mentions 'target ARN' which clarifies that the topic_arn parameter can accept SNS target ARNs (for platform endpoints), adding slight semantic value beyond the schema's 'SNS topic ARN' description, but does not elaborate on parameter interactions or validation rules.

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 states a specific verb ('Publish') and resource ('SNS topic or target ARN'), clearly distinguishing this from sibling read operations like aws_sns_list_topics or aws_sns_get_topic_attributes. It accurately scopes the operation to messaging functionality.

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'), which functions as a when-not-to-use signal. However, it lacks positive guidance on when to choose this over alternatives like aws_sqs_send_message or aws_lambda_invoke, and does not mention prerequisites such as topic existence or IAM permissions.

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