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

With no annotations, the description carries the full burden and does excellently. It discloses that the operation is mutating (create/overwrite), requires admin privileges, never returns the stored value, and rejects temporary STS credentials. This goes beyond what the schema provides and clearly sets expectations.

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?

Three sentences, each earning its place: purpose, requirement/constraint, and return behavior. It is front-loaded with the core function and immediately provides essential usage details. No filler.

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 tool's simplicity (3 required params, no output schema), the description fully covers purpose, authentication requirements, parameter constraints, and expected response behavior. It lacks nothing critical for an agent to invoke the tool correctly and understand the outcome.

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 coverage is 100%, so the baseline is 3. The description adds valuable context beyond the schema by explaining that all three parameters are required and that accessKeyId and secretAccessKey must be from a permanent IAM user (not STS). This gives meaningful guidance for choosing correct parameter values.

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 ('Store') with explicit create/overwrite semantics, names the resource (AWS CloudWatch monitoring credentials), and clearly distinguishes from the sibling set_investigation_datadog_credentials by specifying 'CloudWatch'. It is unambiguous and precise.

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: ADMIN only, and requires permanent IAM keys rather than temporary STS credentials. It implies that this tool is for CloudWatch credentials specifically, but it does not explicitly mention alternatives like set_investigation_datadog_credentials or when to choose one over the other, so it misses the full when-not-to-use guidance.

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