MCP Datadog Server

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

No annotations are provided, so the description carries the full burden. It discloses that the tool checks API key validity and returns a 403 for invalid keys, which is useful behavioral context. However, it doesn't cover other aspects like rate limits, side effects, or response format for valid keys. The description adds some value but leaves gaps.

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 is two sentences, front-loaded with the core purpose and followed by error behavior. Every word earns its place—no redundancy or fluff. It's efficiently structured and appropriately sized for the tool's simplicity.

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 low complexity (0 parameters, no output schema, no annotations), the description is somewhat complete but lacks depth. It covers the basic operation and error case but doesn't explain what a successful validation returns or any broader context. For a validation tool with no structured fields, more detail on outcomes would be helpful.

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?

The tool has 0 parameters, and schema description coverage is 100%. The description doesn't need to explain parameters, and it correctly implies no inputs are required. Baseline is 4 for zero-parameter tools, as there's no parameter information to add beyond the schema.

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 clearly states the tool's purpose: 'Check if the API key (not the APP key) is valid.' It specifies the verb ('check') and resource ('API key'), and distinguishes between API and APP keys. However, it doesn't explicitly differentiate from sibling tools, as there are no obvious validation siblings in the list.

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 minimal guidance: it mentions checking API key validity and notes a 403 error for invalid keys. However, it doesn't specify when to use this tool versus alternatives (e.g., other authentication checks), prerequisites, or integration context. No explicit when/when-not instructions are given.

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