Compares each day's metric to your personal trailing average and returns a z-score, flagging values beyond ±2 as unusual for you.
Each day's value against your own trailing baseline, with a z-score. |z| > 2 is unusual for you.
| Name | Required | Description | Default |
|---|---|---|---|
| metric | No | steps | |
| window_days | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden, and it does add useful behavioral meaning by explaining the z-score threshold for unusual values. However, it does not state whether the tool is read-only, what data source it uses, or any access constraints, leaving operational transparency incomplete.
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 two short sentences with no wasted language, and the core concept plus the interpretation threshold are front-loaded. It is appropriately sized for a simple analytics tool.
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?
The tool is simple and has an output schema, so the description need not explain return shape. Still, for a two-parameter tool with 0% schema description coverage and no annotations, the description leaves important invocation details and sibling differentiation unaddressed.
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 0%, so the description must explain the two parameters. It only vaguely implies a daily metric and a trailing baseline window, without clarifying what `metric` accepts, what `window_days` controls, or what the defaults mean.
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 communicates that the tool computes each day's value against a personal trailing baseline and returns a z-score. It does not explicitly distinguish this from siblings such as monthly_trends or compare_periods, so it stops 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?
The description gives an interpretation rule for the output (|z| > 2 is unusual), but it does not say when to use this tool versus alternatives like monthly_trends or compare_periods. There are no exclusions or context-setting instructions for selecting this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.