Close the browser when the work is finished

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

With no annotations, the description carries the full burden and does so well: it discloses the cross-session safety behavior (other sessions' tabs are untouched, the browser closes itself once they finish) and the fallback idle safety net. It does not state whether the call is idempotent or what a repeat call returns, which is the only remaining gap.

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 prerequisite is front-loaded in the first sentence and every sentence carries information. The closing clause ('reopening costs a few seconds, but closing mid-work makes the next step start over') restates the earlier don't-call-mid-work point at slightly more length than needed.

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-param, output-schema-less lifecycle tool, the description covers timing, side effects, cross-session side effects, and the failure mode of misuse. An agent has everything needed to call it correctly and nothing required 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?

The tool takes zero parameters, so the baseline is 4 and there is nothing for the description to disambiguate. It correctly avoids inventing parameter detail.

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 and resource ('closes this session's browser') along with the exact precondition for calling it. The scope caveat (shared-browser tabs from other sessions are never closed) further sharpens what the tool does, and no sibling tool overlaps with this lifecycle role.

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 an explicit when ('only at the very end', with three concrete completion conditions), an explicit when-not ('don't call it between rounds of edits'), and the cost rationale for the exclusion. Nothing is left to inference.

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