Compose a XCP-420 compliant fair launch. XCP-420 is a community standard that enforces fixed parameters: 10M supply, 4.2M soft cap, 0.1 XCP per mint, 1000 tokens per mint, 1000 block duration, no premine, no commission, burn payment, locked supply. Only the asset name, start block, and descriptio...
AI agents invoke compose_xcp420_fairminter to trigger actions in 21e14. 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
asset | string | Yes | Asset name to create (4-12 uppercase chars, cannot start with A) |
address | string | Yes | Source Bitcoin address |
inputs_set | string | — | Comma-separated UTXOs to use as inputs (txid:vout) |
description | string | — | Asset description |
start_block | integer | Yes | Block height when minting starts. Must be a future block. Minting runs for exactly 1000 blocks. |
sat_per_vbyte | number | — | Fee rate in satoshis per virtual byte (e.g. 1, 5.5, 0.15). Check get_fee_estimate for current market rates. |
Parameters from the server's own tool schema.
This tool composes a blockchain transaction that launches a token fair minter on the Counterparty/Bitcoin network. While 'compose' suggests transaction construction rather than broadcast, it creates an on-chain financial instrument (token issuance with XCP payments and burn mechanics). It involves financial commitments (0.1 XCP per mint, burn payment) and triggers external blockchain operations.
From the tool's definition Compose a XCP-420 compliant fair launch... enforces fixed parameters: 10M supply, 4.2M soft cap, 0.1 XCP per mint, 1000 tokens per mint, 1000 block duration, no premine, no commission, burn payment, locked supply
Documented attack patterns abuse exactly the kind of access compose_xcp420_fairminter gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and 21e14, and nothing reaches the server without passing your rules. This is the rule we recommend for compose_xcp420_fairminter:
{
"version": "1",
"default": "deny",
"tools": {
"compose_xcp420_fairminter": {
"limits": [
{
"counter": "compose_xcp420_fairminter_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}compose_xcp420_fairminter stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Compose a XCP-420 compliant fair launch. XCP-420 is a community standard that enforces fixed parameters: 10M supply, 4.2M soft cap, 0.1 XCP per mint, 1000 tokens per mint, 1000 block duration, no premine, no commission, burn payment, locked supply. Only the asset name, start block, and description are configurable. It is categorised as a Execute tool in the 21e14 MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
compose_xcp420_fairminter accepts 6 parameters: asset, address, inputs_set, description, start_block, sat_per_vbyte. Required: asset, address, start_block. The full parameter table on this page comes from the server's own tool schema.
Register the 21e14 MCP server in PolicyLayer and add a rule for compose_xcp420_fairminter: 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 21e14. Nothing to install.
compose_xcp420_fairminter 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 compose_xcp420_fairminter 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 compose_xcp420_fairminter. 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.
compose_xcp420_fairminter is provided by the 21e14 MCP server (@21e14/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from 21e14, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
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