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

Annotations cover read-only/idempotent/non-destructive, and the description adds substantial non-obvious behavior: start is inclusive while end is EXCLUSIVE, results are overlap-based rather than containment-based, tz changes whether start/end are UTC instants or wall-clock, and a data-quality caveat flags zones whose upstream feed stopped (GB, 2021-06-15) so missing announcements are not mistaken for zero outages. That last item is exactly the kind of silent-failure disclosure an agent needs.

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?

Dense and front-loaded: the resource identification comes first, then boundary semantics, then the timezone rule, then the data-gap caveat. No filler, though the telegraphic phrasing and unexplained 'UMM' acronym cost a little clarity.

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?

Because an output schema exists, return values need not be described, and the description handles the trickiest aspects (boundary inclusion, overlap, timezone, stale feeds). It is incomplete on the non-time parameters (min_mw, kind, zone), which is the remaining gap for a 6-parameter 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 0%, so the description must carry all six parameters — it explains start, end, and tz well, but zone, kind (default 'generation', implying other values exist) and especially min_mw (units/meaning of the threshold) are undocumented anywhere. Partial compensation only.

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 the resource precisely — 'Generation-unit unavailability events (UMM)' — which clearly differentiates it from the sibling get_generation (actual generation output). It does not explicitly name the sibling it could be confused with, and the UMM acronym is left unexplained, so it falls just short of a 5.

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?

Usage is implied by the window semantics ('An outage is returned if it overlaps the window'), which tells the agent how to query but not when to prefer this tool over get_generation or compare_zones. No explicit when-to-use or exclusion guidance is given.

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