Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description fully explains output structure, execution model (agent executes, no caching), concurrency (parallel_group), and a key requirement (browser). Minor omission: no explicit statement about side effects, but the tool appears read-only.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.