Get Oncall Schedule Summary

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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), and the description adds real behavioral context beyond them: the auto-splitting/merging of ranges that exceed the upstream cap, and the guarantee that response size is stable regardless of range length. It stops short of describing pagination, error behavior, or what the 'warnings' look like, so it is not exhaustive.

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?

Front-loaded with the core behavior, then a bulleted decision list, then the fallback rule — easy to scan. There is minor redundancy between 'one entry per user per schedule (not raw shifts)' and the later restatement, though the second instance adds the size-stability point.

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?

With an output schema present, the description need not detail return fields, and it still conveys aggregation semantics, constant response size, and range-splitting behavior. Combined with full schema coverage and read-only annotations, an agent has everything needed to call 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?

Schema description coverage is 100%, so all five parameters are already documented in the schema, which sets the baseline at 3. The description only reinforces the date-range semantics (long ranges split and merged) and does not touch team_ids, schedule_ids, or the include_user_ids toggle, so it adds little parameter-level meaning.

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?

States a specific verb and resource ('Get compact on-call schedule summary for a date range') and immediately defines the return granularity ('one entry per user per schedule, not raw shifts') with aggregated hours. It is clearly differentiated from list_shifts, so an agent can pick between them without opening either 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?

Explicitly enumerates the three conditions that select this tool (aggregated hours, coverage overview, responder load analysis) and names the alternative with the inverse condition ('For individual shift times, or for one person's schedule, use list_shifts instead'). Both when-to-use and when-not-to-use are covered.

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