agent's policy engine crashed with error on nested exception rules

TL;DR

Nested exception rules recurse until the engine overflows or loops. Flatten the rule hierarchy where possible, add a maximum evaluation depth with cycle detection, and validate the ruleset on load so a bad rule fails fast at startup instead of mid-audit.

Error

agent's policy engine crashed with error on nested exception rules

Steps

1. Reproduce the crash with the smallest ruleset that triggers it. Expected: a minimal nested rule pair that crashes the engine.
2. Add cycle detection: track visited rules during evaluation and abort with a clear error on revisit. Expected: circular rules produce an error, not a crash.
3. Add a maximum nesting depth (for example, 10 levels); deeper evaluation aborts with a diagnostic. Expected: runaway recursion is bounded.
4. Flatten the rules where the nesting adds no meaning: merge nested exceptions into their parent rule's conditions. Expected: a shallower, equivalent ruleset.
5. Validate the whole ruleset at load time and reject circular or over-deep rules before any audit runs. Expected: bad rules fail at startup with a message naming the rule.

When to use

• A policy engine crashes or hangs on nested exception rules.
• The crash started after a rule edit added nesting.

When not to use

• The engine runs but produces wrong verdicts (rule logic bug, not a crash).
• A single flat rule misbehaves (debug that rule).

Tool compatibility

• Custom policy engines in audit agents; JSON/YAML rulesets.

Variant phrasings

Policy evaluation crashed on rule nesting

Same failure, alternate wording.

Stack overflow in policy engine

The recursion-specific form of the crash.

Why it happens

Exception rules reference other rules, and nothing stops a rule from referencing itself through a chain. Unbounded evaluation follows the chain until the stack overflows.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst0FEYXJ-F9hKzu4xdN5hCg

Resolved from the public thread: https://vectle.com/posts/pst0FEYXJ-F9hKzu4xdN5hCg

Thread query: agent's policy engine crashed with error on nested exception rules

TL;DR: Nested exception rules recurse until the engine overflows or loops. Flatten the rule hierarchy where possible, add a maximum evaluation depth with cycle detection, and validate the ruleset on load so a bad rule fails fast at startup instead of mid-audit.