browser_set_localstorage

A write tool on the Looking Glass MCP server.

SERVERLooking Glass SOURCElooking-glass-mcp

Medium RISK CLASS

Category Write

Parameters 22 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-sahib-sawhney-wh-looking-glass-mcp/browser-set-localstorage.md

WHAT IT DOES

What browser_set_localstorage does on Looking Glass

AI agents use browser_set_localstorage to create or update resources in Looking Glass, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Looking Glass environment.

Parameter	Type	Required	Description
`key`	string	Yes	Storage key
`value`	string	Yes	Storage value

Parameters from the server's own tool schema.

RISK

Why browser_set_localstorage is rated Medium

Setting localStorage values modifies client-side persistent data reversibly. This is a Write operation—data can be changed or cleared. Severity is medium because localStorage modifications could affect application behavior, session state, or persistence of sensitive data, but the blast radius is limited to the current browser context and the operation is reversible (unlike Destructive actions).

From the tool's definition Tool name 'browser_set_localstorage' indicates modification of browser local storage; sibling tools like 'browser_clear_storage' and 'browser_clear_mocks' confirm this server manipulates browser state. The 'set' verb denotes data creation/modification.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs browser_set_localstorage safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Looking Glass, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For browser_set_localstorage, this is the rule to start with:

browser_set_localstorage Rate-limited

browser_set_localstorage stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "browser_set_localstorage": {
      "limits": [
        {
          "counter": "browser_set_localstorage_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Looking Glass, apply this rule, and every browser_set_localstorage call is checked against it from then on.

FAQ

Questions about browser_set_localstorage

What does the browser_set_localstorage tool do? +

browser_set_localstorage is a write tool on the Looking Glass MCP server. It is categorised as a Write tool in the Looking Glass MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does browser_set_localstorage accept? +

browser_set_localstorage accepts 2 parameters: key, value. Required: key, value. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on browser_set_localstorage? +

Register the Looking Glass MCP server in PolicyLayer and add a rule for browser_set_localstorage: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Looking Glass. Nothing to install.

What risk level is browser_set_localstorage? +

browser_set_localstorage is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit browser_set_localstorage? +

Yes. Add a rate_limit block to the browser_set_localstorage rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block browser_set_localstorage completely? +

Set action: deny in the PolicyLayer policy for browser_set_localstorage. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides browser_set_localstorage? +

browser_set_localstorage is provided by the Looking Glass MCP server (looking-glass-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Looking Glass, and thousands of servers like it.

This server

All 71 Looking Glass tools →

Across the catalogue

emit_assumption_set on 0sec →set-prioity on Kanban MCP Server →team_manager_set_sources on Team Manager MCP → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →