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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds only that the value reported is 'summed' duration over a window plus the backing endpoint, but says nothing about aggregation granularity, grouping of results, or rate limits — modest added context beyond the annotation.

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 with the core purpose front-loaded ahead of the filters. The trailing 'All Quiet: GET /v1/on-call-report/sum.' restates the operation as an endpoint reference, a minor redundancy, but the text is otherwise free of padding.

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 no output schema, the description should ideally indicate what the report returns (e.g., summed duration grouped by user/team/tier) and the window/format expectations beyond the schema's ISO8601 notes. It leaves the return shape entirely unspecified, which is the main remaining gap for a read-only report tool.

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 both required (start/end) and optional (teamId, userId, maxTier) parameters are already documented in the schema. The description's mention of user/team/escalation-tier filtering mirrors the schema without adding format or syntax detail beyond it.

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 a summed on-call duration report over a time window.' The scope (time window, optional user/team/tier filters) is explicit, and it is plainly distinguishable from siblings like allquiet_who_is_on_call and allquiet_list_on_call_overrides, which serve different purposes.

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 implies when the tool applies (reporting on summed on-call duration within a window) and notes the optional filtering dimensions, but gives no explicit when-to-use vs. when-not-to-use guidance and never names an alternative tool for related questions.

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