Replaces the active browser proxy and recreates the context; use a persistent profile to keep state, otherwise cookies are lost when switching mid-session.
Replace the current proxy. This recreates the BrowserContext (state is preserved if --profile-dir was used; otherwise cookies are lost).
| Name | Required | Description | Default |
|---|---|---|---|
| proxy | Yes | New proxy URL. Switching mid-session recreates the context. |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose the critical side effect: the BrowserContext is recreated, so state survives only if --profile-dir was used, otherwise cookies are lost. That is exactly the kind of destructive consequence an agent needs. It omits proxy URL format/validation and return behavior, but the main behavioral trait is covered.
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?
Two tight sentences with the action front-loaded and the side effect following immediately. Every clause earns its place; nothing is padded.
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-parameter mutation tool with no annotations and no output schema, the description covers the essential behavioral consequence and the state-preservation condition. It could say more about proxy URL expectations, but nothing critical for correct invocation 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 description coverage is 100%, so the single 'proxy' parameter is already documented as a URL string with the context-recreation note. The description only restates the mid-session recreation effect, adding no syntax, format, or validation detail beyond the schema.
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 ('Replace') and resource ('the current proxy'), and is immediately distinguishable from sibling setters like cloak_set_fingerprint or cloak_set_timezone. An agent can tell exactly what this tool mutates.
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 description implies this is the tool to call to change the active proxy, but gives no explicit when-to-use guidance, no prerequisites (e.g. whether a proxy must already exist, whether it should be called before navigation), and no alternatives to weigh. Usage is implied by the verb rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.