Framework design upload

examples/tool-invocation.md

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+# Tool invocation (draft)
+
+## Scenario
+User asks for DNS lookup.
+
+## Flow
+- Intent: "resolve A/AAAA for example.com"
+- Constraints: no network egress beyond DNS, low risk, small budget
+- Tool broker requests cap for `dns_lookup` tool
+- Tool runner executes with only required network access
+- Output is validated, logged as an Event, and returned
+