AI agents use set_chunk_option to create or update resources in Ast Editor — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ast Editor environment.
The tool modifies code or configuration by setting chunk options (likely in contexts like R Markdown, Jupyter notebooks, or similar structured code). This is a Write operation as it creates or modifies data reversibly, typical of AST-based surgical edits. Severity is medium because misconfigured chunk options could affect code execution behavior but are typically reversible.
From the tool's definition Tool name 'set_chunk_option' combined with server description's emphasis on 'edit files surgically via Abstract Syntax Trees' and sibling tools like 'add_cell', 'add_field', 'add_method' which modify code/data structures.
Documented attack patterns abuse exactly the kind of access set_chunk_option gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Ast Editor, and nothing reaches the server without passing your rules. This is the rule we recommend for set_chunk_option:
{
"version": "1",
"default": "deny",
"tools": {
"set_chunk_option": {
"limits": [
{
"counter": "set_chunk_option_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_chunk_option 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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set_chunk_option. It is categorised as a Write tool in the Ast Editor MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Ast Editor MCP server in PolicyLayer and add a rule for set_chunk_option: 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 Ast Editor. Nothing to install.
set_chunk_option 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 set_chunk_option 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 set_chunk_option. 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.
set_chunk_option is provided by the Ast Editor MCP server (kambleakash0/agent-skills). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Ast Editor, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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59 Ast Editor tools catalogued and risk-classified — across an index of 43,000+ MCP servers.