AI agents use linear_add_comment to create or update resources in Sage MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Sage MCP environment.
This tool creates new data (a comment) in a reversible manner. Comments can be edited or deleted, making it a Write operation rather than Destructive. The severity is medium because while it modifies project data, the blast radius is limited to adding potentially misleading or spam comments to issues, which could disrupt workflows but doesn't cause data loss or financial impact.
From the tool's definition Tool name 'linear_add_comment' combined with description 'Add a comment to a Linear issue' indicates creation of new comment data on an issue tracking system.
Documented attack patterns abuse exactly the kind of access linear_add_comment gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sage MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for linear_add_comment:
{
"version": "1",
"default": "deny",
"tools": {
"linear_add_comment": {
"limits": [
{
"counter": "linear_add_comment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}linear_add_comment 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 comment to a Linear issue. It is categorised as a Write tool in the Sage MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Sage MCP server in PolicyLayer and add a rule for linear_add_comment: 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 Sage MCP. Nothing to install.
linear_add_comment 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_add_comment 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_add_comment. 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_add_comment is provided by the Sage MCP server (sagemcp/sagemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 359 Sage MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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359 Sage MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.