Pay: trial enable

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

Annotations already declare this is a mutation (readOnlyHint=false) that is non-destructive, but the description goes further by disclosing scope ('Changes only this project setting and leaves the others as they were') and the exact reversal path (undo with pay_trial_disable). It doesn't discuss permissions or propagation timing, but the added scoping and reversibility detail is meaningful beyond the annotations.

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?

Three sentences, front-loaded with the core action first, then the effect on end users, then the undo/disambiguation tail. Every sentence carries distinct information with no redundancy.

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 parameterless toggle with no output schema, the description covers the action, its user-visible consequence, its scope of change, and its reversal, plus sibling disambiguation. An agent has everything needed to call it correctly and safely.

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, which is the baseline-4 case per the rubric, and there is no parameter syntax for the description to elaborate. Nothing is missing or misrepresented on this dimension.

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 ('Enable') and resource ('app engagement trial') and explains the effect precisely: project-wide trial so users without a subscription get free app access at the longest trial length among active plans. It also distinguishes itself from siblings by pointing to pay_trial_disable as the undo and explicitly separating itself from pay_offers_create.

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?

Provides clear context by naming the counterpart tool (`pay_trial_disable`) for reversal and flagging that this is unrelated to offer trial rewards (`pay_offers_create`), which steers the agent away from a plausible wrong sibling. It stops short of spelling out a full set of preconditions or an explicit 'use this when X' rule, so it isn't a 5.

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