zen_sync_barrier

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

Covers blocking behavior, polling, and timeout, but with no annotations, missing details on error handling (e.g., timeout expiration), side effects, or what happens if a tab is closed.

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?

Highly concise with front-loaded summary, a practical note, and a clear parameter list. No unnecessary words.

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?

Covers main purpose and parameters but does not specify return value or error scenarios. For a 4-parameter tool with no output schema, this leaves some gaps.

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?

With 0% schema coverage, description compensates effectively: clearly explains each parameter's purpose, provides an example for predicate, and notes defaults for timeout and poll_interval.

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?

Description clearly states the core function: block until a JS predicate returns truthy on every listed tab. It differentiates from hand-rolled loops but does not explicitly distinguish from sibling wait tools like zen_wait_for_element.

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?

Implies use for synchronizing multiple tabs and replacing manual loops, but lacks explicit when-to-use vs alternatives, prerequisites, or exclusions like closed tabs or timeout behavior.

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