Analytics over time

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety and repeatability are covered for the agent. The description adds only that results are time-bucketed series, with no mention of default interval behavior, range limits, or aggregation windows. Some added context, but not rich beyond the annotations.

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?

Labelled sections (Purpose / Not for / Returns / Use when) with the scope statement front-loaded and zero redundant sentences. Every line earns its place.

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 a read-only analytics tool with no output schema, the definition covers purpose, exclusions, and use conditions well; the 'Returns: Time-bucketed metric series' line is thin on which metrics are included and what the default bucketing is, leaving a small gap an agent might need.

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 67%: from/to carry ISO-date descriptions, and interval is a self-documenting enum, so the schema largely carries the load. The description never mentions the parameters, adds no format or default guidance (e.g., default interval, max range) that the schema lacks.

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 (email metrics bucketed) and resource (analytics over time), and explicitly distinguishes itself from plunk_get_campaign_stats and plunk_get_top_campaigns by shape of output (trend vs. total vs. ranking). An agent can route without opening the schema.

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?

Contains both a 'Not for' exclusion naming the two relevant siblings and a 'Use when' condition (direction/trend questions: rising opens, bounce spikes, a given week). The selection logic is fully spelled out.

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