AI agents use write to create or update resources in Astrograph — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Astrograph environment.
This tool modifies files (reversible operation), placing it in the Write category rather than Read or Execute. It is not Destructive because writes are reversible and the tool doesn't delete or overwrite without recovery options. Severity is medium because unintended file writes could corrupt source code or configs, but the blocking mechanism on duplicates and warnings on similarity provide some protection.
From the tool's definition 'Write file' - the tool creates or modifies file contents. The description explicitly states it 'Write[s] file', which is a reversible data modification operation. The blocking/warning mechanisms do not change the fundamental write capability.
Documented attack patterns abuse exactly the kind of access write gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Astrograph, and nothing reaches the server without passing your rules. This is the rule we recommend for write:
{
"version": "1",
"default": "deny",
"tools": {
"write": {
"limits": [
{
"counter": "write_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}write 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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Write file. Blocks if duplicate exists, warns on similarity. It is categorised as a Write tool in the Astrograph MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Astrograph MCP server in PolicyLayer and add a rule for write: 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 Astrograph. Nothing to install.
write 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 write 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 write. 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.
write is provided by the Astrograph MCP server (thaylo/astrograph). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Astrograph, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
12 Astrograph tools catalogued and risk-classified — across an index of 43,000+ MCP servers.