Load of a trainer

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful behavior beyond that: the start-month attribution rule and the data-coverage cutoff ('engagements are recorded up to mid-October 2026: a later month returns zero'), which prevents an agent from misreading a zero as no activity.

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?

Two short sentences, front-loaded with what is counted, followed by the two rules an agent needs (month attribution, data cutoff). No filler or restatement of the title.

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 two-parameter aggregate tool with annotations and an output schema, the description covers the computation, the temporal attribution rule, and the dataset limitation. Nothing an agent needs to call it correctly and interpret a zero result 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?

Schema coverage is 100%, so the baseline is 3; the description earns a bump by clarifying the semantics of the month parameter — a session counts in the month it starts, not the month it spans. It adds no format detail beyond the schema's YYYY-MM pattern, but the attribution rule is meaning the schema does not carry.

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 computed resource: count sessions a trainer is engaged for in one month plus days billed. This is clearly an aggregate per-trainer/per-month metric, which an agent can distinguish from the sibling session-listing tools (session_detail, sessions_in_week) without opening any schema.

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?

It gives real usage context: the count is drawn 'from the trainer engagements' and a session is attributed to the month it starts in, which tells the agent how to choose the month argument. It stops short of naming an alternative or stating when not to use it, so no explicit routing guidance.

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