AI agents use set_default_cwd to create or update resources in Coding Tools MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Coding Tools MCP environment.
The tool modifies the default working directory state for subsequent operations, which is a reversible configuration change rather than data creation/modification or code execution. This is Write-category because it alters system state, but severity is low because: (1) the change is reversible (can be reset), (2) it affects only the agent's session scope, (3) it lacks destructive or execute-level impact.
From the tool's definition Tool name 'set_default_cwd' indicates modification of runtime state (default current working directory). No description provided to confirm scope.
Documented attack patterns abuse exactly the kind of access set_default_cwd gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Coding Tools MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for set_default_cwd:
{
"version": "1",
"default": "deny",
"tools": {
"set_default_cwd": {
"limits": [
{
"counter": "set_default_cwd_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_default_cwd 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_default_cwd. It is categorised as a Write tool in the Coding Tools MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Coding Tools MCP server in PolicyLayer and add a rule for set_default_cwd: 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 Coding Tools MCP. Nothing to install.
set_default_cwd 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_default_cwd 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_default_cwd. 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_default_cwd is provided by the Coding Tools MCP server (xytom/coding-tools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 18 Coding Tools MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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18 Coding Tools MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.