Check whether a list of translation keys exist in a namespace. Returns: found keys, missing keys. Use this to verify that all t() calls in a component are backed by server entries.
AI agents call check_keys_exist to retrieve information from Localization without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
env | string | — | Which environment to check against (default: sandbox) |
keys | array | Yes | List of translation keys to check |
namespace | string | Yes | Namespace slug |
projectSlug | string | Yes | Project slug |
Parameters from the server's own tool schema.
This tool only queries and verifies the existence of translation keys without modifying, creating, or deleting any data. It is a read-only verification operation with no side effects. The low severity reflects minimal blast radius—a malicious agent could only probe the translation key namespace.
From the tool's definition Tool description states it 'Check[s] whether a list of translation keys exist' and 'Returns: found keys, missing keys.' The verb is 'check' and the return values are informational (what exists/what's missing).
Attacks that exploit this kind of access
Check whether a list of translation keys exist in a namespace. Returns: found keys, missing keys. Use this to verify that all t() calls in a component are backed by server entries. It is categorised as a Read tool in the Localization MCP Server, which means it retrieves data without modifying state.
check_keys_exist accepts 4 parameters: env, keys, namespace, projectSlug. Required: keys, namespace, projectSlug. The full parameter table on this page comes from the server's own tool schema.
Register the Localization MCP server in PolicyLayer and add a rule for check_keys_exist: 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 Localization. Nothing to install.
check_keys_exist is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the check_keys_exist 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.
Set action: deny in the PolicyLayer policy for check_keys_exist. 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.
check_keys_exist is provided by the Localization MCP server (localization-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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