get_volume_trends

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

The readOnlyHint annotation already signals a safe read, and the description adds meaningful behavioral context: it reads from the local index, auto-refreshes if stale or empty, and does not hit live IMAP, so results reflect the last sync. This goes beyond the annotation and helps set expectations about data freshness.

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 three sentences with no filler: purpose first, then use cases, then data-source caveat and alternative. Every sentence earns its place and the structure is easy to scan.

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 simple one-parameter, read-only tool with no output schema, the description is complete: it states the return value (daily inbound/outbound counts), the trailing-window scope, when to use it, and the data-source behavior. No critical context is missing.

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?

The single parameter 'days' is fully documented in the schema with a default and description. The tool description does not add extra meaning beyond the schema, so the baseline of 3 applies.

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 specific verb and resource: 'Return daily inbound and outbound message counts for a trailing window.' It clearly states what the tool does and differentiates it from the sibling get_email_analytics by noting that tool handles sender-level breakdowns and hourly patterns.

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?

Explicit use cases are provided: 'spot volume spikes, identify quiet periods, or track communication trends over time.' It also gives an explicit alternative: 'Prefer get_email_analytics for sender-level breakdowns and hourly patterns,' which tells the agent when not to use this tool.

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