monthly_trends

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

With no annotations, the description carries the full burden. It discloses relevant behavior: output includes mom_pct, dates use YYYY-MM-DD, and home_only removes travel days. It does not state that the operation is read-only, whether start/end are inclusive, or what happens when dates are omitted, leaving meaningful behavioral gaps for an aggregation tool.

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 short and front-loaded, leading with the output shape before parameter quirks. Each sentence adds information; it could be slightly more organized by grouping the date-format note with start/end, but there is no wasted text.

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?

An output schema exists, so return values need not be explained, and the description covers key quirks like mom_pct, home_only, and metric defaults. But with no annotations and 0% schema coverage, gaps remain around read-only status, date-boundary behavior, and when to use it versus siblings like compare_periods and rolling_baseline.

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 0%, so the description must compensate. It explains home_only semantics, the date format for start/end, and that metrics default to a core set with overview() for valid keys. It does not clarify omission behavior for start/end (e.g., whether null means all available history) or whether date bounds are inclusive, so coverage is partial.

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 states a specific resource and computation: monthly averages per metric with month-over-month percent change (mom_pct). It is clear what the tool produces. It does not explicitly distinguish itself from siblings like compare_periods or rolling_baseline, which keeps it from 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?

It gives useful context for two parameters: home_only=True drops travel days, and metrics default to the core set with overview() as the reference for all keys. However, it does not say when to choose this tool over compare_periods, rolling_baseline, or overview, nor does it describe exclusion cases.

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