Mixpanel MCP Server

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It mentions the time scope ('last day') and ranking behavior ('ranked by volume'), but lacks critical details like whether this is a read-only operation, potential rate limits, authentication requirements, or what happens if no events exist. For a tool with no annotation coverage, this is insufficient.

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 extremely concise—two sentences with zero waste. It front-loads the core purpose and efficiently adds output details. Every word earns its place, making it easy to parse quickly.

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 no annotations, no output schema, and 2 parameters with full schema coverage, the description is minimally adequate. It covers the basic purpose and output format but lacks behavioral context (e.g., safety, limits) and detailed usage guidelines. For a simple read tool, it meets the bare minimum but leaves gaps.

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%, so the schema fully documents both parameters ('type' with enum/default and 'limit'). The description adds no parameter-specific information beyond implying ranking by volume, which doesn't clarify parameter usage. Baseline 3 is appropriate when the schema does the heavy lifting.

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: 'Get the most common events over the last day. Returns event names ranked by volume.' It specifies the verb ('Get'), resource ('most common events'), time scope ('last day'), and output format ('ranked by volume'). However, it doesn't explicitly differentiate from sibling tools like 'query_events' or 'frequency_report', which prevents a perfect 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 'frequency_report', nor does it specify prerequisites, exclusions, or appropriate contexts. The user must infer usage from the purpose alone.

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