Create or update a Solidity file in the workspace
AI agents use create_solidity_file to create or update resources in Foundry MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Foundry MCP Server environment.
This tool creates or updates Solidity source files, which are reversible write operations. It does not delete data (Destructive), execute code (Execute), or involve financial transactions (Financial). The severity is medium because modifying Solidity files could introduce vulnerabilities if an AI agent writes malicious contract code, but the impact is limited to the workspace until the code is deployed on-chain.
From the tool's definition Tool description explicitly states 'Create or update a Solidity file', indicating reversible file creation/modification operations. The name 'create_solidity_file' and description 'Create or update a Solidity file in the workspace' confirm write semantics.
Documented attack patterns abuse exactly the kind of access create_solidity_file gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Foundry MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_solidity_file:
{
"version": "1",
"default": "deny",
"tools": {
"create_solidity_file": {
"limits": [
{
"counter": "create_solidity_file_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_solidity_file 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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Create or update a Solidity file in the workspace. It is categorised as a Write tool in the Foundry MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Foundry MCP Server MCP server in PolicyLayer and add a rule for create_solidity_file: 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 Foundry MCP Server. Nothing to install.
create_solidity_file 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 create_solidity_file 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 create_solidity_file. 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.
create_solidity_file is provided by the Foundry MCP Server MCP server (praneshasp/foundry-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 16 Foundry MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
16 Foundry MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.