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

With no annotations, the description carries full behavioral burden. It usefully discloses two traits: the output is unsigned (no transaction is sent) and it is permissionless ('anyone can send it'). It does not state what happens if the drand round is not yet out, whether the payload expires, or the shape of the returned unsigned transaction.

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?

A single front-loaded sentence with no filler; the resource prefix comes first and the timing condition second. Minor density cost from jargon ('drand round') that is never unpacked.

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 two-parameter prepare tool with full schema coverage and no output schema, the description covers purpose, timing, and permission model adequately. It leaves a gap on error behavior and on how this stage relates to the launch/claim siblings, which is the main thing an agent must get right.

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%, including a note that attemptId comes 'from the launch' and that wallet is used only for reads/simulation, so the schema does the heavy lifting. The description adds no parameter meaning beyond what is already documented, so baseline 3 applies.

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 action (prepare an unsigned reveal) on a specific resource (a vehicle heist attempt), with the actor constraint ('anyone can send it'). However, it never differentiates itself from the adjacent sibling tools prepare_vehicle_heist_launch and prepare_vehicle_heist_claim, so an agent must infer which stage this belongs to.

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?

'Once its drand round is out' gives a concrete gating condition for when the tool is callable, which is real usage context. It stops short of naming when-not or pointing to prepare_vehicle_heist_launch / prepare_vehicle_heist_claim as the alternative stages.

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