Perform a surgical text replacement in a file. Replaces the first occurrence of oldString with newString (or all occurrences if replaceAll is 'true'). This is safer than rewriting the entire file because it only touches the specific text you want to change. The oldString must match exactly (inclu...
Accepts file system path (path); Bulk/mass operation — affects multiple targets
Part of the ArcAgent MCP MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use workspace_edit_file to create or modify resources in ArcAgent MCP. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call workspace_edit_file repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach ArcAgent MCP.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
workspace_edit_file:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full ArcAgent MCP policy for all 45 tools.
Agents calling write-class tools like workspace_edit_file have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
Perform a surgical text replacement in a file. Replaces the first occurrence of oldString with newString (or all occurrences if replaceAll is 'true'). This is safer than rewriting the entire file because it only touches the specific text you want to change. The oldString must match exactly (including whitespace and indentation). Paths relative to /workspace.. It is categorised as a Write tool in the ArcAgent MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Add a rule in your Intercept YAML policy under the tools section for workspace_edit_file. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the ArcAgent MCP MCP server.
workspace_edit_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 workspace_edit_file rule in your Intercept 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 Intercept policy for workspace_edit_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.
workspace_edit_file is provided by the ArcAgent MCP MCP server (arcagent-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept