AI agents use linear_addProjectMember to create or update resources in Linear — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Linear environment.
This tool creates a new relationship (project membership) which is a reversible modification of data. It does not execute arbitrary code, delete data permanently, or move money. The action can typically be undone by removing the member.
From the tool's definition Tool name: linear_addProjectMember. Description: 'Add a member to a project'. The verb 'add' indicates a write operation that modifies project membership state by creating a new association between a user and a project.
Documented attack patterns abuse exactly the kind of access linear_addProjectMember gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Linear, and nothing reaches the server without passing your rules. This is the rule we recommend for linear_addProjectMember:
{
"version": "1",
"default": "deny",
"tools": {
"linear_addProjectMember": {
"limits": [
{
"counter": "linear_addprojectmember_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}linear_addProjectMember 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.
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Add a member to a project. It is categorised as a Write tool in the Linear MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Linear MCP server in PolicyLayer and add a rule for linear_addProjectMember: 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 Linear. Nothing to install.
linear_addProjectMember 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 linear_addProjectMember 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 linear_addProjectMember. 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.
linear_addProjectMember is provided by the Linear MCP server (tacticlaunch/mcp-linear). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 182 Linear tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
182 Linear tools catalogued and risk-classified — across an index of 42,500+ MCP servers.