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

With no annotations, the description carries the full behavioral burden. It discloses the cost in sparks and a parked constraint, but omits authentication needs (api_key), whether the purchase is reversible, and what happens after buying—all critical for a mutation tool that spends currency.

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?

The description is very short and front-loads the core action and costs. The second sentence is terse but its 'Cars:' phrasing is ambiguous, which slightly hurts structural 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?

For a mutation tool with no annotations and no output schema, the description is incomplete. It provides cost and a condition but omits auth requirements, purchase side effects, and any indication of what the agent receives, leaving significant gaps for correct invocation.

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 compensate. It adds meaningful cost semantics for the tier enum (select 150, private 500) and a condition for the parked boolean, but it never mentions the required api_key parameter, leaving one of three parameters undocumented.

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?

The description states a clear verb (buy) and resource (income badge), and adds the currency and tier costs. However, the second sentence about 'Cars: only when parked' is cryptic and seemingly unrelated to badges, which slightly muddies the overall purpose.

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?

It gives one usage condition ('Cars: only when parked (parked: true)'), implying that the parked parameter matters only in a specific scenario. But it does not say when to choose this tool over alternatives or when not to use it, leaving overall usage mostly implied.

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