browser_open

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

With no annotations, the description bears the full disclosure burden, but it mostly restates the schema's headless default and adds only the 'point by hand' rationale. It does not say what happens if a browser is already open, whether reopening restores state, what the call returns, or how it can fail.

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 one tight, front-loaded sentence with no filler. The semicolon cleanly separates the open action from the headless/visible guidance, even if the headless default also appears in the schema.

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 tool with seven parameters, nested objects, no output schema, and no annotations, this description is too thin. It omits tool-level behavior around existing browser instances, session restore, return values, and failure modes, so an agent cannot fully predict the tool's effect beyond what the schema implies.

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 schema already covers most parameter meanings and defaults, and the description adds a useful behavioral gloss for headless via 'visible only when you need to point by hand.' However, it does not help with the schema's undocumented parameters like timezoneId or geolocation, leaving the semantics only partially enriched.

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 names a specific verb and resource: 'Open (or reopen) the controlled browser,' so the core action is unmistakable. It does not explicitly contrast itself with sibling tools like browser_status or tab_open, so differentiation comes from the clear verb rather than an explicit comparison.

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 headless/visible guidance is a concrete decision rule: use headless by default, switch to visible only when manual pointing is needed. It does not mention alternatives or exclusion conditions, such as when to use browser_status or tab_open, so it stops short of full routing guidance.

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