browser_open

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

With no annotations, the description carries the full behavioral burden and does so unusually well: it discloses refusal on blocked sites, the return payload (tab id, past_routes with best-first ordering, mine/shared attribution, map_traps), the side effect that all activity is recorded and judged, that the verdict arrives via browser_close, and the exact judging rubric including that safety stops and 'no control' answers are free.

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 correctly with the action in the first sentence, followed by return shape and then the judging rubric. It is dense and jargon-heavy ('map_traps', 'mine/shared', 'one to explore') and the judging clause is long, but every sentence carries operational information rather than filler.

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?

No output schema and no annotations exist, yet the description explains the return values, the feedback loop through browser_close, and the scoring semantics an agent needs to interpret outcomes. For a 5-parameter navigation tool with this much stateful behavior, nothing essential 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 80%, so the schema already documents goal, port, wait_css, and wait_text with real detail including the 9222/9223 warning. The description adds no parameter-level meaning beyond mentioning that past_routes relate to the goal, which the schema itself states. Baseline 3 is appropriate.

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 opening sentence gives a specific verb and resource (open a URL) plus a scoping constraint (in a NEW tab) that implicitly separates it from browser_goto, which presumably reuses the current tab. It stops short of naming that sibling outright, so the differentiation is inferred rather than stated.

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?

Usage is implied rather than prescribed: the goal parameter returning 'past routes' and 'one to explore' hints this is the entry point for starting work on a site. But there is no explicit statement of when to pick this over browser_goto, browser_tabs, or browser_launch, and no prerequisites (port, launch order) are spelled out in the description.

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