Vflow

RTL Flow Orchestrator

Overview

Two responsibilities:

1. State scan — inspect project directories to determine each phase's completion for one IP, then write ./flow_status.md.
2. Flow execution — drive the flow by invoking the right skill at the right time, pausing at checkpoints, and looping the debug-fix-retest cycle.

Input is an IP name, optionally followed by a mode keyword.

Resolve the IP name before anything else — never guess across IPs. flow_status.md and every downstream skill operate on exactly one IP.

Single-IP-repo assumption. The bundled scanner assumes the repo holds one IP: its Phase 2 and Phase 3 checks scan all of ddoc/*_req.md and rtl/ rather than scoping to _top's hierarchy. With one IP this is exact. If a repo ever holds two IPs, those two phase counts would mix submodules across IPs — scope them to the _top instantiation hierarchy before relying on the scan (see the note in scan.sh).

• Name given → use it.
• Not given, exactly one candidate top-level requirement .md in the project root (a .md that is not CLAUDE.md, flow_status.md, or other generated/status doc) → use it.
• Not given, two or more candidates → stop and ask the user which IP (list the candidates). No heuristic pick; never run more than one IP per invocation.
• Not given, no candidate → stop and report none found.

Invocation modes

| Invocation | Behavior | |------------|----------| | vflow [] | Scan and execute (default): Step 1 → Step 2 → Step 3. | | vflow [] status (also scan, --scan-only, --dry-run) | Scan only: Step 1 → Step 2, present flow_status.md, then stop. Touch no file but flow_status.md; invoke no downstream skill. |

Step 1 - Scan Project State

Never Read a whole .md to compute a status symbol. All status comes from existence / mtime / grep/awk counts, which the bundled scanner already does. (Enumerating RTL_BUG locations for the Step 2 open-issues display is a targeted grep of debug_summary.md, not a whole-file read — that is allowed.) Run the scanner once from the project root; do not reissue per-check commands inline:

bash /scan.sh 

` is the directory containing this SKILL.md (the running copy — repo skills/vflow/ or the global ~/.claude/skills/vflow/). Resolve scan.sh` as the sibling of this file. If it cannot be located or it errors out, fall back to performing the same existence/mtime/count checks inline rather than skipping the scan.

Greenfield is normal. A brand-new IP has only ./ddoc/.md and no ./rtl yet (Phase 1 creates rtl/). The scanner treats a missing ./rtl as the pre-architecture state and reports P1 PENDING (everything downstream PENDING) — it does not error. ERR: is emitted only when ./ddoc itself is absent (you are not at a project root). So on a greenfield run, proceed straight to Phase 1 (varch); do not treat P1 PENDING as a problem.

It prints one compact line per phase signal: P1 DONE|PENDING, P2 d/n, P3 left=N, P4 DONE|PENDING, P5 RUN|SCAFFOLDED|NONE, P7 DONE|PENDING, and (only when a run exists) FAILED=N, DEBUG=current|stale|none, plus RTLBUG=N when DEBUG=current. A ? value (FAILED=?, RTLBUG=?) means the count row was malformed/absent in run_summary.md/debug_summary.md — inspect that file's breakdown manually rather than assuming 0. RTLBUG is read from the classification breakdown in debug_summary.md's Results section; it depends on that section listing a per-class count. If it prints ERR: …, you are not at a project root or the layout is non-standard — stop and resolve that.

Phase status from the scan output

| Phase | DONE | Otherwise | |-------|------|-----------| | 1 – Architecture | P1 DONE | PENDING | | 2 – Design | P2 d/n with n>0 && d==n | ⚠ IN PROGRESS (d/n); n==0 means nothing to design yet → PENDING (Phase 1 not DONE), never DONE | | 3 – Implementation | P3 left=0 (and Phase 2 DONE) | ⚠ IN PROGRESS (markers remain) | | 4 – Synthesis | P4 DONE | PENDING | | 5 – IP Testing | P5 RUN | ⚠ IN PROGRESS if SCAFFOLDED, else PENDING | | 6 – Debug | FAILED=0, or DEBUG=current with RTLBUG=0 | failures + DEBUG=none/stale → debug pending; DEBUG=current with RTLBUG>0 → ⚠ IN PROGRESS (awaiting fix) | | 7 – Documentation | P7 DONE | PENDING |

Caveats (one rule each):

• Phase 3 reports marker state only — absence of //@ is not proof lint/sim passed. Sim-pass is enforced at execution time (Phase 3 pauses on failure), so a re-scan must not upgrade a module on marker absence alone while a known sim failure is unresolved.
• Phase 6 currency — vtestrun overwrites run_summary.md each re-test while a prior debug_summary.md lingers; DEBUG=stale means that report predates the latest run and does NOT satisfy Phase 6. Treat debug as not-yet-run for the current failures.

Step 2 - Write flow_status.md

Overwrite ./flow_status.md (a live snapshot, not history).

• Header — IP name and scan date.
• Phase table — one row per phase. Symbols: ✓ DONE, ⚠ IN PROGRESS (N/M), ✗ PENDING, ✗ BLOCKED (), ✗ ERROR (). BLOCKED = a prerequisite phase isn't DONE; ERROR = the phase's skill aborted (see Orchestration Rules).
• Next action — one line for the immediate next step. Normally a skill invocation + target (e.g. vfill → rtl/foo_ctrl.v). May instead be a non-skill state: wait (parked at a user gate, e.g. WAITING on user RTL fix (Phase 6B)), blocked (what must finish first), or error (which phase errored).
• Open issues (only if run_summary.md shows FAILED>0) — the Failed count. If DEBUG=current, list each RTL_BUG root-cause location (one line per unique location); if stale, note debug must be re-run.

Step 3 - Execute the Flow

Scan-only mode stops here — present flow_status.md and invoke no skill.

Otherwise execute the next incomplete phase. A DONE phase is skipped entirely.

---

Phase 1 — Architecture [CHECKPOINT]

When: Phase 1 PENDING.

Run varch on the IP requirement file; it writes ddoc/_arch.md and derives the per-submodule _req.md files and rtl/_top.v.

Checkpoint: present the module decomposition and interfaces; wait for explicit approval. On change requests, edit ddoc/_arch.md and re-run varch (it regenerates only affected submodules and reports the change set), then re-present. No advance without approval.

---

Phase 2 — Design [CHECKPOINT per submodule]

When: Phase 2 PENDING or IN PROGRESS.

For each submodule in ddoc/ lacking rtl/.v:

1. Run vdesign on ddoc/_req.md.
2. Checkpoint: present that proposal; wait for approval before the next submodule. Revise and re-present on change requests.

One at a time. Do not batch-approve.

---

Phase 3 — Implementation [AUTO]

When: Phase 3 PENDING or IN PROGRESS.

Run vfill on each rtl/.v (not _top.v) that still has //@ markers. The top skeleton's //@ are integration notes, not fill directions — never vfill it.

Process pending submodules sequentially, no checkpoints. If vfill fails lint or sim, report and pause — do not continue while errors are unresolved.

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Phase 4 — Synthesis [AUTO]

When: Phase 3 DONE, Phase 4 PENDING.

Run vsynth on the full IP — target the top module _top, so the report lands at synth/_top/synth_report.md (the path the scan checks). No checkpoint; include the Fmax/utilization one-liner in the status and continue.

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Phase 5 — IP Testing [AUTO]

When: Phase 4 DONE, Phase 5 PENDING or IN PROGRESS.

Run vtestgen (scaffold + generate the suite), then vtestrun. If the bench is already scaffolded with tc_list.md (was IN PROGRESS), resume — don't re-scaffold. After vtestrun, read FAILED:

• 0 → skip Phase 6, go to Phase 7.
• >0 → Phase 6.

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Phase 6 — Debug and Fix Loop [AUTO + GATE]

When: Phase 5 DONE and failures exist.

6A — Debug

Run vdebug in batch mode on the IP.

6B — Gate: await user RTL fix

Present: total open failures; every RTL_BUG (classification, file, module, block, one-line description); TC_BUG entries (need testcase fixes); DOC_AMBIGUITY entries (need clarification). State explicitly: "RTL fixes are required before the flow can continue. Signal when fixes are applied."

TC_BUG/DOC_AMBIGUITY don't block. If no RTL_BUG remains, skip the gate and go to Phase 7.

6C — Re-test after fix

On the user's signal:

1. Run vtestrun again — the test result is ground truth that the fix took effect. vtestrun rebuilds every testcase whose RTL/TB sources are newer than its last simulate.log; an RTL fix touches rtl/, so all dependent testcases re-simulate (a regression in a previously-passing testcase is caught, not skipped) while unrelated results are reused. (This overwrites run_summary.md, making the old debug_summary.md stale per the currency rule.)
2. New failures → run vdebug on them (writes a current debug_summary.md) and return to 6B.
3. None → Phase 7.

Repeat until clear or the user stops.

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Phase 7 — Documentation [AUTO]

When: all prior phases DONE and no open RTL_BUG. That precondition is established by 6B/6C, or by Phase 5 with zero failures — Phase 7 is reachable only those ways; by any other path, return to Phase 6.

Run vdoc on the IP. Then re-run Step 1–2 (scan + write flow_status.md) — not the whole skill — and present the all-DONE status as the completion summary.

---

Orchestration Rules

• Never skip a CHECKPOINT.
• Never re-run a DONE phase unless asked.
• Never proceed past a Phase 3 lint/sim failure.
• Stop on any phase abort. A result (skill completed, reported failures/timing miss) is handled by the phase's rules; an abort (missing input, crashed tool, exception, malformed artifact) is not — stop, mark the phase ✗ ERROR (), surface the skill's output verbatim, never advance. Applies to the [AUTO] phases too. (Tool-unavailable is the one pre-classified abort → ✗ BLOCKED, below.)
• No RTL probe cleanup needed. vdebug never edits rtl//lib/; its probes live only in a disposable testbench include and vdebug removes them.
• Always update flow_status.md after each phase.
• Never fabricate tool output. If a required tool is absent (Vivado for P4, xsim for P5), mark that phase ✗ BLOCKED (tool unavailable: ), report it, and continue scanning the rest.

Known Issues and Fixes

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: phamcuong21478
• Source: phamcuong21478/rtl-skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.