compare_zonesCompare one endpoint across multiple zones.
start/end default to UTC; start inclusive, end EXCLUSIVE.
tz="local" is rejected (zones may differ); pass an explicit IANA
tz like "Europe/Berlin" if you need wall-clock alignment.
| Name | Required | Description | Default |
|---|---|---|---|
| tz | No | ||
| end | Yes | ||
| start | Yes | ||
| zones | Yes | ||
| endpoint | Yes | ||
| aggregation | No | daily |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds non-obvious behavioral details beyond the readOnlyHint/idempotentHint annotations: UTC defaults, start inclusive/end exclusive boundaries, and rejection of tz='local'. These are exactly the kind of edge-case behaviors an agent needs to avoid incorrect calls.
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 compact and well structured: one core sentence followed by three terse lines of boundary/timezone semantics. Every sentence adds useful information and there is no filler or repetition of the schema.
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 that output schema covers return shape and annotations cover safety, the description covers the main calling gotchas around timezone handling and interval boundaries. The main missing piece is aggregation semantics, but the tool remains usable for typical calls.
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?
With 0% schema description coverage, the description partly compensates by explaining start, end, and tz semantics, and lightly defining endpoint/zones via the first sentence. However, aggregation is not described at all, and endpoint/zones are not tied to the list_endpoints/list_zones tools, leaving a partial gap.
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 opens with a concrete verb and object: 'Compare one endpoint across multiple zones.' This clearly states the tool's action, resource, and scope, and distinguishes it from sibling tools like get_series or list_zones that are not specifically about cross-zone comparison.
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 does not say when to choose this tool over alternatives or when not to use it. The only usage-related note is the tz caveat, which is about parameter formatting rather than tool selection, so an agent gets no explicit routing guidance among the sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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