omp's resolveApproval resolves in three layers: tool declaration → user override → mode tier. Undeclared or malformed approvals default to exec (fail-closed). Tool declares tier + optional policy/override/reason/policyKey; user overrides via tools.approval.<tool>; mode (always-ask/write/yolo) sets auto-allow tier ceiling. Iron laws: tool-side deny and user-side deny can never be crossed by mode; yolo ignores override: true but still honors policy: deny|allow|prompt. bash tokenizes approval: allow must cover whole line, deny/prompt match per segment. Same tool switches read/write via policyKey. checkpoint/rewind are paired sisters. subagent runs headless yolo; parent task is the only auth boundary.
omp's bash approval engine tokenizes commands into segments via a shared shell tokenizer (split on `;`, `&&`, `||`, `|`, `&`, newline, subshell). deny/prompt rules match glob against each segment individually — any hit triggers. allow rules require whole-line match AND no shell control syntax, preventing `cd x && rm -rf /` from slipping through. CRITICAL_BASH_PATTERNS hardcodes 45 dangerous command regexes (`rm -rf /`, `chmod -R 777 /`, `curl | bash`, `kill -9 1`, etc.) that fire before user patterns and cannot be disabled. Design tradeoff: allow is strict for safety, deny/prompt permissive for catch-all.
Looplane now grades effects as read/modify/modify_execute/execute and fails closed on unclassified tools. Native MCP tools default to execute unless trusted read-only metadata lowers them. Approval events still land in events.jsonl first and grants can scope to one change set or backend; general command rules and universal sandbox coupling remain unfinished.
All five projects combine allow/ask/deny decisions, compound-command inspection, and fail-closed behavior. looplane now has a deny-first classifier, critical floor, shell segmentation, timeout-deny, configured allow/deny rules, and visible policy reasons. Broader syntax coverage and live interactive validation remain open.
The biggest problem when an agent enters CI is approval: no TTY, nobody to click approve. The five reference projects converge on two strategies — delegate permission decisions to the calling program (claude-code's control protocol), or replace approval semantics entirely (codex defaults to Never plus sandboxing, opencode auto-rejects). looplane keeps one AgentRunner loop and injects a different ApprovalPolicy: headless uses HeadlessApprovalPolicy, which never reads stdin so it cannot hang the pipeline, and denies EXECUTE by default — fail closed.