# Eng > Platform-agnostic engineering agent with three modes: --plan (propose file changes for human approval AND write the per-feature todo tickets in the same pass), --build (write code from the todo tickets — the single and final build spec), --review (one adversarial whole-change review of the working diff, run by a separate reviewer subagent — spawned by --build automatically, and available standalone on any branch at any time). Use --review when the user says "review this change", "review my diff", "code review this branch", or invokes /eng --review. Invoked by plan-em or directly by the user. - Skill: `ndisisnd/eng` (Agent Skill, multi-file: 12 files) - Install (CLI): `npx skillmds@latest add ndisisnd/eng` - Raw SKILL.md: https://api.skillmd.com/api/skills/ndisisnd/eng/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: ndisisnd (https://skillmd.com/u/ndisisnd) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/ndisisnd/eng --- # eng Platform-agnostic engineering agent with three modes — `--plan`, `--build`, `--review` — each a distinct protocol in its own ref file, selected by the invocation flag. This file routes; the shared spine that runs for every mode is `refs/protocol-core.md` (Steps 0–6), and it never runs a mode's work itself. ## Routing (Step 0 — full rules in `refs/protocol-core.md`) Read the invocation flag and load exactly one mode protocol: | Flag | Read | |------|------| | `--plan` | `refs/plan/protocol.md` | | `--plan report=` | `refs/plan/fix-plan.md` (instead of `protocol.md`) | | `--build` | `refs/build/protocol.md` — **unless an orchestrator spawned you as a build packet**, in which case read `refs/build/protocol-packet.md` instead and stop; it is the whole leaf contract | | `--build report=` | `refs/build/fix-build.md` (instead of `protocol.md`) | | `--review` | `refs/review/protocol.md` | **Natural-language triggers for `--review`:** "review this change", "review my diff", "code review this branch", "adversarial review", "look for bugs in what I just wrote". Anything asking for *style, naming or standards* is `/cook`, not this mode. **`--quiet` / `--status m`** (`--build` only) — heartbeat control; flag beats policy beats default (`../shared/refs/status-heartbeat.md`). Exactly one mode flag must be present — zero, several, or the retired `--todo` hard-fail with the exact messages in `refs/protocol-core.md` § Step 0. Then read the active mode file **fully** and run the spine end-to-end: ## The shared spine (`refs/protocol-core.md`) - **Step 1 — Input validation.** PRD/exec-table source (mode flag + `prd-path` + `rows` + `agent`, hard-refuse on any missing) or the `report=` alternate; more than one source is a hard failure. `--review` is exempt from Steps 1–4 — its input is the working diff; go straight to Step 5. - **Step 2 — Pre-flight, one pass.** Orchestrated fast path works from injected scoped excerpts (full PRD only as escape hatch); standalone path reads the full PRD, verifies row ownership mechanically via `script-prd-digest.py --verify-rows`, and reads devkit + the row-relevant codebase in parallel. - **Step 3 — Summary + approval gate.** 3–4 line summary, then `AskUserQuestion` (Yes / needs correction / follow-up → the Step 3a interview). Never proceed without an explicit "Yes, proceed" (pre-approved under an autonomy contract). - **Step 4 — Coding standards (`--build` only).** Injected standards payload wins; else derive the `/cook` flag set and consult the persistent standards cache (`script-standards-cache.py`) before calling `/cook` (v5.6.5; `../shared/refs/session-cache.md` § Consumers). - **Step 5 — Run the active mode's work** per its ref, then the closing message (`../shared/refs/closing-message.md`) as the last chat output, doctor-logging harness incidents (`../shared/refs/doctor-logging.md`). - **Step 6 — Scope enforcement, continuous.** Only the assigned rows; unresolvable ambiguity is surfaced as a gap (plan/review) or blocks and asks (build) — never resolved by assumption. ## References - `refs/protocol-core.md` — the shared spine, Steps 0–6: routing + hard-fail messages, input validation, pre-flight, approval gate + interview, standards resolution, mode dispatch, scope enforcement - `refs/plan/protocol.md` — `--plan`: summary content, output contract, exact-identifier rule, **the `## Todos — ` ticket-writing spec** run in the same pass, and the mechanical closing check. `refs/plan/template-todo.md` — the ticket schema `--build` reads mechanically. `refs/plan/template-eng-plan.md` — the two output shapes and the rule that picks between them. `refs/plan/fix-plan.md` — the `report` source for planning fixes - `refs/build/protocol.md` — `--build`: branch contract, `report` source, coding-standards flag table, work steps, the Step-5a whole-change review spawn, commit/PR contract. `refs/build/protocol-packet.md` — the **orchestrated build leaf's** self-contained fast path, read *instead of* protocol.md and this file when a leaf is spawned by `plan-em`; keeps the db-touch pause and the v5.3 review artifact. `refs/build/fix-build.md` — `report` source + the finding→issue-ticket projection and `kind` discriminator - `refs/review/protocol.md` — `--review`: change-set resolution, reviewer inputs, the adversarial charter + exclusion list, the A4 what-vs-how exception, severity discipline (`source: eng:review`), the blocker/high-before-commit-confirm rule, the JSON return contract, the subagent spawn rules. One review, whole-change, run by an agent that did not write the code - `.claude/scripts/` — `script-eng-db-touch.sh` (production/data guardrail; a tripped check pauses for sign-off) · `script-eng-comment-scan.sh` (deterministic A4 comment scan) · `script-eng-commit-cap.sh` (A5 commit-size measurement, advisory; the `Oversize-reason:` trailer pairing is not — `TRAILER_MISSING`, exit 3) · `script-eng-plan-shape.py` (the `--plan` closing check, eight fail-loud checks) · `script-project-findings.py` (the ONE finding→issue-ticket projection + issues-file validator; read-only, shared with `--gui`) · `script-eng-fix-grade.py` (the executable fix-complexity rubric + tier→model mapping; escalate `simple`→`complex`, never downgrade) · `script-eng-close-loop.py` (the only sanctioned write to an issues file) - `../shared/refs/status-heartbeat.md` — the `--quiet`/`--status` heartbeat contract - **Contract:** the `## Engineering — ` and `## Todos — ` headings written by `--plan` (same pass) are how `plan-em` detects the section is ready and how `--build` locates its spec. Do not rename them.