Submit a message to an HCS topic. Messages up to 1KB are sent as single chunk. Larger messages automatically split into chunks (max 20). For private topics, provide submitKey or ensure operator key is in address book.
AI agents invoke message_submit to trigger actions in HashPilot. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool triggers an external blockchain operation by submitting messages to Hedera Consensus Service (HCS) topics. It causes real effects on the Hedera network (on-chain transactions), which incur fees and are immutable once submitted. While it doesn't directly move money, it executes transactions on a live blockchain.
From the tool's definition Submit a message to an HCS topic... Larger messages automatically split into chunks... For private topics, provide submitKey
Attacks that exploit this kind of access
Submit a message to an HCS topic. Messages up to 1KB are sent as single chunk. Larger messages automatically split into chunks (max 20). For private topics, provide submitKey or ensure operator key is in address book. It is categorised as a Execute tool in the HashPilot MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the HashPilot MCP server in PolicyLayer and add a rule for message_submit: 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 HashPilot. Nothing to install.
message_submit is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the message_submit 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 message_submit. 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.
message_submit is provided by the HashPilot MCP server (justmert/hashpilot). 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.
Teams ship this data inside their own products. See what a licence covers →