Create (or upsert) an environment variable on a Vercel project. Target defaults to production, preview, and development. Use type='plain' for non-secret values, 'encrypted' or 'sensitive' for secrets.
AI agents use vercel_create_env to create or update resources in UnClick — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your UnClick environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
key | string | Yes | |
type | string | — | plain | encrypted | sensitive | secret | system. Defaults to plain. |
value | string | Yes | |
target | string | — | CSV of environments: 'production,preview,development'. Defaults to all three. |
upsert | boolean | — | Overwrite existing value for same key/target. Default true. |
api_key | string | — | |
comment | string | — | |
team_id | string | — | |
git_branch | string | — | |
project_id | string | Yes |
Parameters from the server's own tool schema.
This tool creates or modifies environment variables on a live Vercel project deployment. While reversible (upsert means it can be updated), it affects production, preview, and development targets by default. Misuse could compromise application secrets, API keys, or critical configuration. The ability to set encrypted/sensitive values increases risk.
From the tool's definition Tool description explicitly states 'Create (or upsert) an environment variable on a Vercel project', indicating reversible creation/modification of configuration data. Supports both plain and encrypted/sensitive values.
Risk signalsHandles credentials or secrets (api_key) · High parameter count (10 properties)
Attacks that exploit this kind of access
Create (or upsert) an environment variable on a Vercel project. Target defaults to production, preview, and development. Use type='plain' for non-secret values, 'encrypted' or 'sensitive' for secrets. It is categorised as a Write tool in the UnClick MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
vercel_create_env accepts 10 parameters: key, type, value, target, upsert, api_key, comment, team_id, git_branch, project_id. Required: key, value, project_id. The full parameter table on this page comes from the server's own tool schema.
Register the UnClick MCP server in PolicyLayer and add a rule for vercel_create_env: 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 UnClick. Nothing to install.
vercel_create_env is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the vercel_create_env 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 vercel_create_env. 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.
vercel_create_env is provided by the UnClick MCP server (@unclick/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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