Mixpanel MCP 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 of behavioral disclosure. It mentions the tool 'Returns recent events for a specific user,' which implies a read-only operation, but doesn't cover critical aspects like authentication requirements, rate limits, pagination, error handling, or the format of the returned events. This leaves significant gaps for a tool with no annotation support.

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 front-loaded, consisting of two clear sentences that directly state the tool's purpose and output. There's no wasted verbiage, making it efficient for quick understanding, though it could be slightly more structured with bullet points or explicit sections for better readability.

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 complexity (retrieving user activity data with three required parameters), lack of annotations, and no output schema, the description is incomplete. It fails to address behavioral aspects like authentication, rate limits, or return format, and doesn't provide usage guidelines relative to siblings. This leaves the agent under-informed for effective tool invocation.

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 100% description coverage, clearly documenting all three required parameters (distinct_id, from_date, to_date). The description adds no additional parameter semantics beyond what's in the schema, such as explaining the meaning of 'distinct_id' or date format nuances. With high schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate but also doesn't detract.

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 with a specific verb ('Get') and resource ('user's activity stream'), and specifies what it returns ('recent events for a specific user'). However, it doesn't explicitly differentiate from sibling tools like 'query_events' or 'export_events', which might also retrieve event data, so it doesn't reach the highest score.

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 no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'query_events' or 'export_events', nor does it specify any prerequisites, exclusions, or contextual cues for usage, leaving the agent without clear direction.

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