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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds little behavioral context beyond restating that it returns counts and properties, and the output schema presumably covers return shape. No contradiction exists, but the description does not add significant behavioral detail such as pagination, date-inclusivity, or rate limits.

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: one purpose sentence, one output sentence, and a compact example. It is front-loaded and avoids filler, though the example is somewhat redundant with the schema examples.

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?

For a read-only query tool with full schema coverage, rich annotations, and an output schema, the description covers the essentials: purpose, input shape via example, and output type. It does not explicitly distinguish from sibling analytics tools, but this is a minor gap given the tool's simplicity and the structured metadata available.

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%, with every parameter already documented in the input schema. The description's example repeats those values but does not add new semantic meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 and resource ('Query event data from Mixpanel') and states the output ('event counts and properties'). It does not explicitly name sibling tools like get_funnels or get_retention, but the general event-query focus is clear enough to distinguish it from those specialized analytics tools.

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 clearly states the tool is for querying Mixpanel event data within a date range, and the example demonstrates a realistic invocation. It does not explicitly mention when not to use it or point to alternatives, but the context is clear and sufficient for a straightforward data-query tool.

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