AI agents use tool_replace_block to create or update resources in UltimateCoder — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your UltimateCoder environment.
The tool name 'replace_block' implies modifying or overwriting a specific block of code or text within a file, which is a reversible write operation. Given the server's focus on code manipulation and file handling, and the presence of file-modification sibling tools, this is best classified as Write rather than Destructive (since replacement of a specific block is theoretically reversible, unlike deletion).
From the tool's definition T ool na me 'tool_repl ace_bl ock' s u gg est s mo di fyi ng co nt ent wit hi n a fil e; si bli ng to ol s in clu de 'tool_appl y_pat ch' and 'tool_del et e_pat h' wh ich a re Write/Destra cti ve, con fi rmi ng this is a fil e-ma nip ul ati on server.
Documented attack patterns abuse exactly the kind of access tool_replace_block gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and UltimateCoder, and nothing reaches the server without passing your rules. This is the rule we recommend for tool_replace_block:
{
"version": "1",
"default": "deny",
"tools": {
"tool_replace_block": {
"limits": [
{
"counter": "tool_replace_block_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}tool_replace_block 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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tool_replace_block. It is categorised as a Write tool in the UltimateCoder MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the UltimateCoder MCP server in PolicyLayer and add a rule for tool_replace_block: 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 UltimateCoder. Nothing to install.
tool_replace_block 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 tool_replace_block 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 tool_replace_block. 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.
tool_replace_block is provided by the UltimateCoder MCP server (m-ahmed-elbeskeri/ultimatecodermcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from UltimateCoder, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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23 UltimateCoder tools catalogued and risk-classified — across an index of 43,000+ MCP servers.