get_volume_trends

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

The annotations already declare readOnlyHint=true, so the description does not need to state safety. The description adds behavioral context by specifying the output (daily counts) and the time scope (trailing window). This is sufficient for a simple read tool, but it does not disclose potential rate limits or pagination, which keeps it from a 5.

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 sentences with no extraneous information. The first sentence defines the purpose, and the second provides usage guidance and an alternative. Every word contributes value.

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 has one optional parameter, no output schema, and is read-only. The description fully covers what the tool does (returns daily counts), when to use it, and how it differs from a sibling. There is no missing information for an agent to invoke it correctly.

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 input schema has 100% coverage for the single parameter 'days,' including a description and default value. The tool description does not add additional semantics beyond 'trailing window,' which echoes the schema. Since schema coverage is high, a baseline score of 3 is appropriate.

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 states the tool returns 'daily inbound and outbound message counts for a trailing window,' which is a specific verb-resource combination. It distinguishes itself from the sibling 'get_email_analytics' by noting that this tool is for volume trends while the alternative is for 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?

The description explicitly says to use this tool to 'spot volume spikes, identify quiet periods, or track communication trends' and advises to 'prefer get_email_analytics for sender-level breakdowns and hourly patterns.' This provides clear when-to-use and when-not-to-use guidance, including a specific alternative.

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