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

Adds substantial behavior beyond the thin annotations (destructiveHint only): asynchronous earning-rule evaluation that may issue points or rewards, idempotency semantics with the specific rejection case for duplicate token+distinct_id, plan gating, and required scope. This tells the agent the side effects and failure mode of a write it cannot see from the schema.

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-loaded with 'WRITE:' and the core action, then packed with operational constraints in a few dense sentences; little is wasted. It is information-heavy rather than elegantly trimmed, but every sentence carries weight.

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 output schema, no return-value description is strictly required, and the description covers async processing, idempotency, scope, and plan requirements for a 5-parameter write tool. Only a note on what the call returns or how the async outcome is observed 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 100%, so the baseline is 3, but the description adds real meaning: token is a token configured in Smile Admin, distinct_id is exemplified as an order number, and the customer_id/customer_email mutual-exclusivity rule is stated. It extends rather than repeats the schema.

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?

Opens with an explicit verb+resource ('WRITE: record that a customer performed an action') and pins the resource to a configured activity type token, finishing with the underlying call (Smile: POST /activities). This is clearly distinguishable from the points-transaction and rewards siblings, which record different resources.

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 concrete conditions: exactly one of customer_id or customer_email, use distinct_id to make the call idempotent, custom activity types require Plus/Enterprise, and the activity:write scope is needed. It stops short of naming a sibling alternative (e.g. when to reach for smile_create_points_transaction instead), so it is strong but not exhaustively routing.

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