browser_tab_close
Close a shared browser tab, defaulting to the active one, to end its session and free resources.
Instructions
Close a shared tab (default: the active one).
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| id | No |
Close a shared browser tab, defaulting to the active one, to end its session and free resources.
Close a shared tab (default: the active one).
| Name | Required | Description | Default |
|---|---|---|---|
| id | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. 'Shared tab' hints at a shared browsing context but the description never says whether closing destroys state, whether it affects other clients sharing the tab, what happens to the active tab pointer afterward, or how an invalid/absent id is handled.
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?
A single short sentence with the default behavior front-loaded in parentheses; nothing is wasted. It is terse to the point of under-specification, but brevity itself is handled well.
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 one-optional-parameter tool this is roughly the minimum viable, but with no output schema and no annotations the description leaves return behavior, failure modes, and destructive impact of closing a shared tab unexplained.
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 0% for the single 'id' parameter, so the description must compensate. It does add one meaningful fact — omitting id closes the active tab — which the schema alone does not convey, but it says nothing about accepted id formats or what happens if the id is stale or unknown.
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 (close) and resource (shared tab), which cleanly separates it from siblings like browser_tab_new and browser_tab_select. It does not explicitly name those siblings or describe scope beyond 'shared tab', so differentiation is inferable 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?
There is no guidance on when to close a tab, prerequisites, or what to do instead (browser_tabs, browser_tab_select). The only usage-relevant detail is the default-target note, which is about the parameter rather than about selecting this tool over alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.