get_call_start_distribution

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

No annotations are provided, so the description carries the full burden. It correctly implies a read operation but does not disclose any behavioral traits such as authentication requirements, rate limits, or whether the data is live or cached. For a simple aggregation, the description is adequate but minimal.

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 consists of two sentences with no redundancy. The verb and resource are front-loaded, and every word contributes to understanding. It is appropriately sized for the tool's simplicity.

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 low complexity (2 parameters, no output schema), the description is complete. It explains the input (date), optional filter (agent_id), output format (hourly counts), and use case. No additional details are needed for an AI agent to invoke this tool 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?

Schema coverage is 100% with both parameters described in the schema. The description adds value by explaining the output format ('each hour (0-23)') and reinforcing the date parameter's role. This goes beyond the baseline of 3 by providing additional context not in the schema.

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 uses a specific verb ('Get') and resource ('call start distribution') with clear scope ('by hour for a specific date'). It explicitly states the output ('how many calls started in each hour (0-23)'), which distinguishes it from sibling tools like get_call_counts_by_day or get_call_volume that aggregate differently.

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 provides a usage hint ('Useful for scheduling and capacity planning') but does not explicitly state when not to use this tool or compare it to alternatives. This is implied usage guidance, not explicit exclusion or context for tool selection.

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