Switch the page's identity by loading saved cookies + storage. Use only when switching identity mid-page; for first navigation, pass identity_name to browser.open instead.
| Name | Required | Description | Default |
|---|---|---|---|
| page_id | Yes | ||
| in_workspace | No | Run this one call in this workspace id instead of the session's. Nothing is stored; other sessions are not affected. | |
| identity_name | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / in_workspaceAdded value: +{
+ "description": "Run this one call in this workspace id instead of the session's. Nothing is stored; other sessions are not affected.",
+ "type": "integer"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly/idempotent/non-destructive, and the description usefully adds the mechanism (cookies + storage are loaded). It does not say what happens to the page's existing session/identity data, whether the switch is reversible, or whether the target identity must already exist — which matters for a stateful page mutation.
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 sentences, zero filler, with the operational constraint front-loaded ahead of the redirect to browser_open. Every clause earns its place.
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 three-parameter tool with no output schema and annotations covering the safety profile, the description gives enough to call it correctly and to not confuse it with browser_open. The one remaining gap is what happens to prior page state when the identity is swapped.
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 33% (only in_workspace is documented in the schema). The description implies identity_name refers to a saved identity by referencing saved cookies/storage, but adds no format, discovery, or failure semantics, and page_id is left entirely to the schema. Partially compensates for the coverage gap, no more.
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 and resource — switching the page's identity — and explains the mechanism (loading saved cookies + storage). It also distinguishes itself from browser_open, which handles first navigation, so an agent can route correctly without opening a schema.
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?
Explicitly scoped: 'Use only when switching identity mid-page' tells the agent the trigger condition, and 'for first navigation, pass identity_name to browser.open instead' names the alternative and the condition that selects it. Nothing is left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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