Get Volume Trends

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

Annotations already indicate readOnlyHint=true and openWorldHint=true. The description adds behavioral context by specifying that it returns daily counts and does not include unread counts, which aligns with the read-only nature. There is no contradiction with annotations, and the description adds value beyond what annotations provide.

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 extremely concise, consisting of two short sentences that convey the core purpose, output, and a key exclusion. It is front-loaded with the main action and contains no unnecessary words or redundancy.

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 the tool's simplicity (2 optional parameters, output schema exists), the description is complete. It explains what the tool returns (daily counts of received and sent messages) and what it does not return (unread counts), which is sufficient for an agent to decide when to use it. The output schema handles return value details, so no further description needed.

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?

Both parameters (days and account_id) have detailed descriptions in the input schema (100% coverage). The tool description does not add any additional meaning beyond the schema, such as explaining defaults or behavior when account_id is omitted. Following the guidelines, baseline 3 is appropriate when schema coverage is high and description provides no extra parameter info.

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 it retrieves daily send/receive volume over a time window, indicating the specific output (daily counts). It distinguishes itself from get_unread_count by explicitly noting what it does not include. However, it does not differentiate from other sibling tools like get_email_stats or get_correspondence_profile, which may also provide volume-related data.

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 tells the agent not to use this tool for unread counts and directs to get_unread_count as an alternative. This is a clear exclusion and alternative for one specific case. However, it provides no guidance on when to use this tool over other analytics tools in the sibling list.

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