Store a knowledge item in the shared knowledge base. Use for bug fixes, patterns, decisions, and conventions that should be available to all agents.
AI agents use corn_knowledge_store to create or update resources in CornMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your CornMCP environment.
This tool writes data to a shared knowledge base, creating or modifying entries. It affects a shared resource accessible to all agents, meaning misuse could pollute the knowledge base with incorrect information, but the action is reversible (entries can be deleted or corrected). No code execution, financial transactions, or irreversible destruction is implied.
From the tool's definition 'Store a knowledge item in the shared knowledge base'
Documented attack patterns abuse exactly the kind of access corn_knowledge_store gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and CornMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for corn_knowledge_store:
{
"version": "1",
"default": "deny",
"tools": {
"corn_knowledge_store": {
"limits": [
{
"counter": "corn_knowledge_store_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}corn_knowledge_store 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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Store a knowledge item in the shared knowledge base. Use for bug fixes, patterns, decisions, and conventions that should be available to all agents. It is categorised as a Write tool in the CornMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Corn MCP server in PolicyLayer and add a rule for corn_knowledge_store: 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 CornMCP. Nothing to install.
corn_knowledge_store 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 corn_knowledge_store 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 corn_knowledge_store. 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.
corn_knowledge_store is provided by the Corn MCP server (yuki-20/cornmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 18 CornMCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
18 CornMCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.