Get the custom field values that are currently set on a specific issue
AI agents call linear_getIssueCustomFields to retrieve information from Linear without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves custom field data from an existing issue in Linear. It performs a read-only query operation that returns information without creating, modifying, deleting, or executing any actions. The verb 'Get' and the absence of any state-changing language confirm this is a Read category tool with low severity risk.
From the tool's definition Tool name 'getIssueCustomFields' and description 'Get the custom field values that are currently set on a specific issue' indicate a retrieval operation with no modification or side effects.
Documented attack patterns abuse exactly the kind of access linear_getIssueCustomFields 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_getIssueCustomFields:
{
"version": "1",
"default": "deny",
"tools": {
"linear_getIssueCustomFields": {}
}
}linear_getIssueCustomFields is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get the custom field values that are currently set on a specific issue. It is categorised as a Read tool in the Linear MCP Server, which means it retrieves data without modifying state.
Register the Linear MCP server in PolicyLayer and add a rule for linear_getIssueCustomFields: 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_getIssueCustomFields 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 linear_getIssueCustomFields 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_getIssueCustomFields. 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_getIssueCustomFields 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.