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

The description contributes real behavior beyond the annotations: taking control pauses the character's autopilot. That is useful since the annotations only declare destructiveHint=true, openWorldHint=true, and idempotentHint=false without explaining consequences. It remains silent on cost/rental terms implied by 'rent', duration, and what exactly the destructive hint covers (displacing another controller or losing control on expiry).

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?

Two short sentences, front-loaded with the primary action and immediately followed by the key side effect. Nothing is redundant and nothing could be removed without losing information.

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?

With no parameters and no output schema, the definition is nearly sufficient, but a destructive, non-idempotent, open-world action warrants at least a note on what is lost or displaced and how control ends. The autopilot detail is the only behavioral disclosure provided.

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?

The tool takes zero parameters and the schema is empty, so there is nothing for the description to clarify; baseline 4 applies. No parameter-level ambiguity is introduced.

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 specific verb and resource: 'Take control of a character that lives in the world,' plus the repeat-use case ('renew the one you hold'). It is clearly distinguishable from siblings like release_bot and autopilot through the note that autopilot pauses, though it never names those alternatives directly.

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?

The parenthetical 'or renew the one you hold' tells the agent this tool is also used to extend an existing rental, which is genuine usage guidance. However, it never states when NOT to use it or points to release_bot/autopilot as the alternative paths, leaving routing to inference from the sibling names.

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