Fork a knowledge base scope — creates an independent copy of all facts in the source scope under a new target scope name. Use for hypothetical reasoning ('What if Alice moves to London?') without modifying the main knowledge base. Similar to git branch for knowledge. Side effects: mutates state (...
Part of the Nocturnusai MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents call fork_scope to retrieve information from Nocturnusai without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though fork_scope only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
tools:
fork_scope:
rules:
- action: allowSee the full Nocturnusai policy for all 16 tools.
Agents calling read-class tools like fork_scope have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Read risk category across the catalogue. The same policy patterns (rate-limit, allow) apply to each.
Fork a knowledge base scope — creates an independent copy of all facts in the source scope under a new target scope name. Use for hypothetical reasoning ('What if Alice moves to London?') without modifying the main knowledge base. Similar to git branch for knowledge. Side effects: mutates state (additive) — creates a new scope with copied facts; source scope is unchanged. Auth: requires X-Tenant-ID header; FACT_WRITE permission when auth is enabled. Rate-limited per principal. Errors: VALIDATION_ERROR if targetScope is blank or already exists.. It is categorised as a Read tool in the Nocturnusai MCP Server, which means it retrieves data without modifying state.
Add a rule in your Intercept YAML policy under the tools section for fork_scope. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Nocturnusai MCP server.
fork_scope is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the fork_scope 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 fork_scope. 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.
fork_scope is provided by the Nocturnusai MCP server (nocturnusai-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