reports_series

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

With no annotations provided, the description carries full burden. It discloses a known limitation (intermittent empty responses), explains that debug envelope keys are included when items=0, and compares server-side vs client-side behavior. This exceeds typical disclosure, though it doesn't mention auth or rate limits.

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 well-structured with labeled sections (Required, Optional filters, Known limitation) and front-loads the main action. It's longer than average but each sentence adds operational value, and there's no repetition or filler.

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 complex 19-parameter tool with no annotations, the description covers the core functionality, required parameters, optional filters, operators, debugging behavior, and fallback. The output schema exists, so return-value documentation isn't necessary. Minor omissions like auth/rate limits keep it from a 5.

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 compensates by grouping the 19 parameters into required, optional filters, and operators. It explains the by dimension (referring to reports_series_dimensions), interval granularity, and lists all operators. However, it doesn't individually describe account_ids/account_status, which are less self-evident.

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+resource+scope: 'Get time-series call data aggregated by dimension across sub-accounts.' It further distinguishes itself from siblings by calling it 'the most flexible reporting endpoint' and explicitly mentions a fallback to call_disposition_report, making its purpose unambiguous.

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 clearly states required parameters (start_date, end_date, by, interval) and provides explicit guidance on when to use an alternative: 'fall back to call_disposition_report... works reliably.' This gives the agent concrete conditions for use versus a specific sibling tool.

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