close_browserCloses the browser when the user asks to cancel an active capture. Saved login sessions remain intact for future access.
Close the browser when the user asks to cancel. An active capture will fail; saved login sessions are retained. Do not call during capture unless cancellation is intended.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| message | Yes |
Changes observed during successful MCP inspections.
v4.0.0Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "message": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "message"
+ ],
+ "type": "object"
+}v2.0.7Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations, it discloses the key side effect (an active capture will fail) and the state that survives (saved login sessions are retained), plus the operational constraint about not closing mid-capture. This is precisely the behavioral context annotations cannot convey, and it does not conflict with destructiveHint=false since no persisted data is destroyed.
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?
Three short sentences, front-loaded with the primary action and followed by the side effect and the guardrail. Every sentence carries distinct information with no redundancy.
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 session-control tool with an output schema and full annotation coverage, the description supplies the trigger, the failure mode, and the persistence behavior. Nothing an agent needs to invoke it correctly 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 implies the operation is unconditional on input.
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 states a specific verb and resource ('Close the browser') and ties it to a user intent ('when the user asks to cancel'), so the action is unambiguous. It does not explicitly distinguish itself from the sibling tools, though none of them offer an overlapping close-session capability, so the gap is minor.
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?
It gives an explicit trigger ('when the user asks to cancel') and an explicit exclusion ('Do not call during capture unless cancellation is intended'), which is exactly the when/when-not guidance an agent needs. No alternative tool competes for this action, so no further routing is required.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.