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 key behavioral traits: pagination ('Results are paginated') and rate limiting ('rate limited to 300 requests per hour'). This adds valuable context beyond basic functionality, though it could mention authentication needs or error handling. There is no contradiction with annotations since none exist.

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 concise and well-structured: three sentences covering purpose, usage, and behavioral details, with a reference link for pagination. Each sentence adds value, and it's front-loaded with the core purpose. It could be slightly more streamlined by integrating the link more seamlessly, but it's efficient overall.

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 complexity (a read-only list tool with pagination and rate limits), no annotations, and no output schema, the description is moderately complete. It covers key behaviors but lacks details on authentication, error responses, or example outputs. It's adequate for basic use but has gaps for full agent guidance, especially without an output schema to clarify return values.

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 input schema has 0 parameters with 100% description coverage, so no parameter documentation is needed. The description does not discuss parameters, which is appropriate. Baseline is 4 for 0 parameters, as it avoids unnecessary detail and focuses on other aspects.

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: 'List endpoint returns spans that match a span search query.' It specifies the verb ('List'), resource ('spans'), and scope ('match a span search query'), which is specific and informative. However, it does not explicitly distinguish this tool from sibling tools like 'search_spans_events' or 'aggregate_spans_analytics', which limits the score to 4 instead of 5.

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 some usage guidance: 'Use this endpoint to see your latest spans.' This implies a context for viewing recent data but does not explicitly state when to use this tool versus alternatives (e.g., 'search_spans_events' for filtered searches or 'aggregate_spans_analytics' for aggregated data). It lacks clear exclusions or named alternatives, so it's only implied usage.

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