create_signed_save
Generate a tamper-evident, versioned save-system component (sealed, owner-only). The SaveData payload POCO is serialized to JSON (Sandbox.Json), FNV-1a-64 hashed over payload + version + salt, and written as a signed envelope { Version, Payload, Signature } to FileSystem.Data. Load() re-verifies:...
This record as markdown: /tools/sbox/create-signed-save.md
What create_signed_save does on Sbox
AI agents use create_signed_save to create or update resources in Sbox, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Sbox environment.
Why create_signed_save is rated Medium
Writes game save data reversibly; destructive reset only on detected tampering, not routine use.
From the tool's definition creates signed save-system component, serializes to JSON, writes FileSystem.Data
Attacks that exploit this kind of access
The rule that runs create_signed_save safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Sbox, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For create_signed_save, this is the rule to start with:
create_signed_save 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Sbox, apply this rule, and every create_signed_save call is checked against it from then on.
Questions about create_signed_save
Generate a tamper-evident, versioned save-system component (sealed, owner-only). The SaveData payload POCO is serialized to JSON (Sandbox.Json), FNV-1a-64 hashed over payload + version + salt, and written as a signed envelope { Version, Payload, Signature } to FileSystem.Data. Load() re-verifies: a signature mismatch (hand-edited/corrupt file) triggers a FORCED RESET — the save file is DELETED, defaults are used, and the static OnTampered(reason) event fires (destructive and deliberate; tell the player). A version mismatch starts fresh without the tamper event (add migrations in Load). Loaded values pass a Sanitize() clamp hook so even a re-signed save can. It is categorised as a Write tool in the Sbox MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Sbox MCP server in PolicyLayer and add a rule for create_signed_save: 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 Sbox. Nothing to install.
create_signed_save 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 create_signed_save 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 create_signed_save. 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.
create_signed_save is provided by the Sbox MCP server (sbox-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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