close_browser

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

With no annotations provided, the description must carry the behavioral burden. It does disclose the side effect of serializing a trace transition before closing, which is useful. However, it does not mention irreversibility, session teardown, or what happens to unsaved trace data, leaving some behavior implicit.

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?

The description is a single sentence with no filler. 'Close the brwoser' is front-loaded, and the qualifying serialization behavior is placed at the end, making the core purpose immediately clear.

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 zero-parameter close action with no output schema, the description covers the action and the key ordering constraint. It is complete enough to call correctly; minor details like return value or failure behavior are absent but not critical for this simple operation.

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 has zero parameters and the schema coverage is effectively 100%, so there are no parameter semantics for the description to add. Per the rubric, zero parameters earn a baseline of 4.

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 uses a specific verb ('Close') with a clear resource ('the browser') and adds a sequencing detail ('after serializing any native trace transition'), so an agent knows exactly what action occurs. It does not explicitly compare against sibling tools, but no sibling shares the close-browser action, so it is distinguishable.

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 phrase 'after serializing any native trace transition' gives a clear procedural condition for when it is safe to call this tool. It does not name exclusions or alternatives, but the action itself (closing the browser) is distinct enough that no alternative routing is needed.

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