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

Annotations only declare readOnlyHint and openWorldHint; the description adds meaningful behavior beyond that — a 5–20 second latency window, a cap of 10 offers sorted by total price, a returned link to the full list/map, and a `guidance` field the agent is told to follow when answering. This is exactly the operational context annotations cannot convey.

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-loads the purpose, then the workflow instruction, then the runtime/return contract — a sensible order. The prose is tight and every sentence is actionable, though the three-block layout runs slightly long for the amount of information conveyed.

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 10-parameter, no-output-schema tool, the description covers the key gaps: how to source the ids, latency expectations, result count/sorting, and the `guidance` return value. The remaining battery/energy parameters are adequately covered by the schema, so nothing critical 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 70%, so the schema documents most parameters itself. The description reinforces the provenance of vehicle_id and card_ids (from find_vehicle / list_charging_cards) and implies the place-based 3 km search, but says nothing about battery_start_pct, battery_target_pct, energy_kwh, charger_speed, or accepts_operator_app beyond what the schema already states.

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 (find), resource (chargers), and scope (cheapest, within 3 km of a place, for this car and these cards). An agent can immediately tell this apart from the lookup siblings find_vehicle and list_charging_cards, which are named as inputs rather than alternatives.

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 explicit sequencing: before the first search of a conversation, ask the driver for car and cards in one question, then call find_vehicle and list_charging_cards, and reuse vehicle_id/card_ids afterwards. It names the prerequisite tools and the state to carry forward, leaving nothing to inference.

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