kpi_new_users

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

No annotations are provided, so the description carries the full behavioral burden. It says nothing about whether this is a read-only query, what permissions or API key are required, rate limits, or what granularity/format the time series returns.

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 single sentence is front-loaded and free of filler, which is good. However, it is terse to the point of under-specification for a 5-parameter analytics tool, so it earns only a middling score.

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?

With 5 parameters, no annotations, no output schema, and two undocumented parameters, the description leaves too much unexplained. An agent cannot determine the returned granularity, the time-range semantics, or the authentication expectations from this definition alone.

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 coverage is only 60% and the description adds no parameter meaning at all. It does not explain 'length' (days), 'ending_at' (undocumented in schema), 'app_id' (undocumented), or how they shape the returned series.

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 ('Get') and resource ('new users count') with a temporal scope ('over time'), which cleanly separates it from siblings like kpi_dau, kpi_mau, and kpi_uninstalls. It does not explicitly name those siblings, so it falls short of a 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?

There is no indication of when to use this tool versus the other KPI tools (kpi_dau, kpi_mau) or the users_* analytics tools. No prerequisites, exclusions, or alternatives are given; usage is only weakly implied by the name.

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