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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds only 'Query API: GET /funnels,' which restates the endpoint rather than disclosing anything behavioral. It says nothing about auth requirements, rate limits, or the shape/cost of returned conversion data.

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?

Two short sentences with the purpose front-loaded and no wasted words. The trailing 'Query API: GET /funnels' is mildly redundant but cheap.

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 an 8-parameter read-only query tool with full schema coverage and no output schema, the definition covers the core action and the funnel_id sourcing. It leaves conversion-window semantics to the schema, which is acceptable, though a bit more guidance on interpretation would help.

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 every parameter (unit, limit, length, interval, length_unit, dates) is already documented in the schema. The description adds no parameter meaning beyond that, making the baseline 3 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?

States a specific verb+resource: 'Get conversion data for a saved funnel.' It also points to mixpanel_list_funnels as the source of funnel_id, which helps an agent place it in the workflow. It does not explicitly contrast with mixpanel_segmentation or mixpanel_retention, so it falls just short 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?

Provides one useful prerequisite: use mixpanel_list_funnels to obtain funnel_id. However, it gives no guidance on when to choose this over mixpanel_segmentation or mixpanel_retention, which analyze related but different things.

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