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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, yet the description adds substantial context: est_revenue is gross, energy-only, excludes FCAS, and is not MLF-adjusted, and per-interval dispatch is deliberately not exposed. That is real behavioral disclosure beyond the annotations, though it doesn't discuss auth or rate limits.

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?

Purpose and scope are front-loaded in the first sentence, then the dense field glossary follows. It is long, but with no output schema each clause about return fields and their semantics earns its place; only the packed listing of unit_class/peer_comparable feels slightly dense.

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?

There is no output schema, so the description must carry the return-value burden, and it does: it enumerates every battery row field, defines the response code meanings, sign conventions, and caveats on revenue and FCAS. An agent has everything needed to interpret the response 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 a single required id parameter, so the baseline is 3. The description goes further by telling the agent where the value comes from ('take the id from list_events'), adding sourcing semantics the schema alone does not convey.

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+resource: 'One price event by event_id', immediately distinguishing it from the sibling list_events by being the single-event lookup. The scope (all online batteries, ranked by est_revenue) is also made explicit.

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?

Gives clear sourcing guidance — 'take the id from list_events' — which directs the agent to the prerequisite tool, and warns to check the field labels before comparing units. It stops short of stating when NOT to use this tool versus e.g. get_battery_detail, so it lacks full exclusion guidance.

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