code-modernization: legacy toolchain is advisory, not a transform blocker

Legacy code often cannot build locally by nature — CICS/IMS programs
have no local translator and the real runtime may be a mainframe the
user doesn't have. Stopping transform on a failed legacy smoke compile
would block exactly those systems.

- transform Step 0a: the target toolchain remains required (its tests
  cannot run without it); a failed or impossible legacy compile no
  longer stops the run — the equivalence strategy switches to recorded
  traces / golden-master fixtures, and that downgrade is stated in the
  plan and in TRANSFORMATION_NOTES.md so reviewers know the strength of
  the proof
- preflight: a red legacy toolchain now yields Ready-with-gaps for
  transform/reimagine instead of Not-ready

.claude-plugin/marketplace.json

@@ -752,7 +752,7 @@
     },
     {
       "name": "code-modernization",
-      "description": "Modernize legacy codebases (COBOL, legacy Java/C++, monolith web apps) with a structured assess / map / extract-rules / reimagine / transform / harden workflow and specialist review agents",
+      "description": "Modernize legacy codebases (COBOL, legacy Java/C++, monolith web apps) with a structured preflight / assess / map / extract-rules / brief / reimagine / transform / harden workflow, an interactive topology viewer, and specialist review agents",
       "author": {
         "name": "Anthropic",
         "email": "support@anthropic.com"

plugins/code-modernization/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "code-modernization",
-  "description": "Modernize legacy codebases (COBOL, legacy Java/C++, monolith web apps) with a structured assess → map → extract-rules → brief → reimagine/transform → harden workflow and specialist review agents",
+  "description": "Modernize legacy codebases (COBOL, legacy Java/C++, monolith web apps) with a structured preflight / assess / map / extract-rules / brief / reimagine / transform / harden workflow, an interactive topology viewer, and specialist review agents",
   "author": {
     "name": "Anthropic",
     "email": "support@anthropic.com"

plugins/code-modernization/README.md

@@ -7,7 +7,7 @@ A structured workflow and set of specialist agents for modernizing legacy codeba
 Legacy modernization fails most often not because the target technology is wrong, but because teams skip steps: they transform code before understanding it, reimagine architecture before extracting business rules, or ship without a harness that would catch behavior drift. This plugin enforces a sequence:
 
 ```
-assess → map → extract-rules → brief → reimagine | transform → harden
+preflight → assess → map → extract-rules → brief → reimagine | transform → harden
 ```
 
 The discovery commands (`assess`, `map`, `extract-rules`) build artifacts under `analysis/<system>/`. The `brief` command synthesizes them into an approval gate. The build commands (`reimagine`, `transform`) write new code under `modernized/`. The `harden` command audits the legacy system and produces a reviewable remediation patch. Each step has a dedicated slash command, and specialist agents (legacy analyst, business rules extractor, architecture critic, security auditor, test engineer) are invoked from within those commands — or directly — to keep the work honest.
@@ -20,29 +20,36 @@ Commands take a `<system-dir>` argument and assume the system being modernized l
 mkdir -p legacy && ln -s /path/to/your/legacy/codebase legacy/billing
 ```
 
-## Optional tooling
+## What to give Claude
 
-`/modernize-assess` works best with [`scc`](https://github.com/boyter/scc) (LOC + complexity + COCOMO) or [`cloc`](https://github.com/AlDanial/cloc), and falls back to `find`/`wc` if neither is installed. Portfolio mode also benefits from [`lizard`](https://github.com/terryyin/lizard) (cyclomatic complexity). The commands degrade gracefully without them, but the metrics will be coarser.
+The commands degrade gracefully, but each of these makes the output meaningfully better — run `/modernize-preflight <system-dir>` to check all of them at once and get a readiness report:
 
-## Secret handling
+- **Analysis tools**: [`scc`](https://github.com/boyter/scc) (LOC + complexity + COCOMO) or [`cloc`](https://github.com/AlDanial/cloc); [`lizard`](https://github.com/terryyin/lizard) for portfolio mode. Without them, metrics fall back to `find`/`wc` and get coarser.
-
+- **A working build toolchain** for the legacy stack (e.g. GnuCOBOL for COBOL) — required before `/modernize-transform` can prove behavioral equivalence, and verified by preflight with a real smoke compile against your code.
-Legacy systems routinely contain live credentials, and assessment artifacts get committed and shared. **Every agent in this plugin masks credential values** — findings, rule-card parameters, architecture notes, and test fixtures cite `file:line` with a masked preview (`AKIA****`), never the value. When credentials are found, a per-credential inventory (type, location, blast radius, rotation recommendation) is written to `analysis/<system>/SECRETS.local.md`, which the commands gitignore before writing; on non-git projects the quarantine file goes to `~/.modernize/<system>/` instead. `/modernize-harden` splits its remediation diff so credential-removal hunks (which necessarily contain the raw value) land in a gitignored `security_remediation.local.patch`, never the shareable patch. Pass `--show-secrets` to include raw values in the quarantine file (and only there). If you ran an earlier version of this plugin on a real system, check whether `analysis/` artifacts containing credentials were committed or shared, and rotate anything that was.
+- **The whole system in the tree**: deployment descriptors (JCL, CICS definitions, route configs), copybooks/includes, and DDL/schemas. Entry-point detection and data lineage in `/modernize-map` are guesswork without them.
+- **Production telemetry** (optional): an observability MCP server or batch job logs enable the runtime overlay in `/modernize-assess` and timing annotations on critical paths.
 
 ## Commands
 
 The commands are designed to be run in order, but each produces a standalone artifact so you can stop, review, and resume.
 
+### `/modernize-preflight <system-dir> [target-stack]`
+Environment readiness check, meant to run first: detects the legacy stack, checks analysis tooling, **smoke-compiles a real source file** with the legacy toolchain (the errors this surfaces — missing copybooks, wrong dialect flags — are the ones that otherwise appear mid-transform), inventories missing includes / deployment descriptors / binary-only artifacts, and probes for telemetry. Produces `analysis/<system>/PREFLIGHT.md` with a per-command Ready / Ready-with-gaps / Not-ready verdict.
+
 ### `/modernize-assess <system-dir>`  — or — `/modernize-assess --portfolio <parent-dir>`
 Inventory the legacy codebase: languages, line counts, complexity, build system, integrations, technical debt, security posture, documentation gaps, and a COCOMO-derived effort estimate. Produces `analysis/<system>/ASSESSMENT.md` and `analysis/<system>/ARCHITECTURE.mmd`. Spawns `legacy-analyst` (×2) and `security-auditor` in parallel for deep reads. With `--portfolio`, sweeps every subdirectory of a parent directory and writes a sequencing heat-map to `analysis/portfolio.html`.
 
 ### `/modernize-map <system-dir>`
-Build a dependency and topology map of the **legacy** system: program/module call graph, data lineage (programs ↔ data stores), entry points, dead-end candidates, and one traced critical-path business flow. Writes a re-runnable extraction script and produces `analysis/<system>/topology.json` (machine-readable), `analysis/<system>/TOPOLOGY.html` (rendered Mermaid + architect observations), and standalone `call-graph.mmd`, `data-lineage.mmd`, and `critical-path.mmd`.
+
+![Interactive topology map of AWS CardDemo — domains as containers, modules sized by lines of code, dependency edges colored by kind, entry points ringed](assets/topology-viewer-screenshot.jpg)
+
+Build a dependency and topology map of the **legacy** system: program/module call graph, data lineage (programs ↔ data stores), entry points, dead-end candidates, and 2–4 traced business flows each anchored to a persona (the claimant, the operator, the auditor — not the maintainer). Writes a re-runnable extraction script and produces `analysis/<system>/topology.json` plus `analysis/<system>/TOPOLOGY.html` — an **interactive zoomable map** (circle-pack of domains/modules sized by LOC, dependency edges with per-kind toggles, search, click-for-details sidebar, and a walkthrough mode that plays each persona flow as a numbered path with a plain-language narrative). Built from a template shipped with the plugin, so it works on systems far too dense for a static diagram. Small domain-level `call-graph.mmd`, `data-lineage.mmd`, and `critical-path.mmd` are still exported for docs and PRs.
 
 ### `/modernize-extract-rules <system-dir> [module-pattern]`
 Mine the business rules embedded in the legacy code — calculations, validations, eligibility, state transitions, policies — into Given/When/Then "Rule Cards" with `file:line` citations and confidence ratings. Spawns three `business-rules-extractor` agents in parallel (calculations, validations, lifecycle). Produces `analysis/<system>/BUSINESS_RULES.md` and `analysis/<system>/DATA_OBJECTS.md`.
 
 ### `/modernize-brief <system-dir> [target-stack]`
-Synthesize the discovery artifacts into a phased **Modernization Brief** — the single document a steering committee approves and engineering executes: target architecture, strangler-fig phase plan with entry/exit criteria, behavior contract, validation strategy, open questions, and an approval block. Reads `ASSESSMENT.md`, `TOPOLOGY.html`, and `BUSINESS_RULES.md` and **stops if any are missing** — run the discovery commands first. Produces `analysis/<system>/MODERNIZATION_BRIEF.md` and enters plan mode as a human-in-the-loop gate.
+Synthesize the discovery artifacts into a phased **Modernization Brief** — the single document a steering committee approves and engineering executes: target architecture, strangler-fig phase plan with entry/exit criteria, persona-based business walkthroughs (the section non-technical approvers actually read), behavior contract, validation strategy, open questions, and an approval block. Reads `ASSESSMENT.md`, `TOPOLOGY.html`, and `BUSINESS_RULES.md` and **stops if any are missing** — run the discovery commands first. Produces `analysis/<system>/MODERNIZATION_BRIEF.md` and enters plan mode as a human-in-the-loop gate.
 
 ### `/modernize-reimagine <system-dir> <target-vision>`
 Greenfield rebuild from extracted intent rather than a structural port. Mines a spec (`analysis/<system>/AI_NATIVE_SPEC.md`), designs a target architecture and has it adversarially reviewed (`analysis/<system>/REIMAGINED_ARCHITECTURE.md`), then **scaffolds services with executable acceptance tests** under `modernized/<system>-reimagined/` and writes a `CLAUDE.md` knowledge handoff for the new system. Two human-in-the-loop checkpoints. Spawns `business-rules-extractor`, `legacy-analyst` (×2), `architecture-critic`, and general-purpose scaffolding agents.
@@ -50,6 +57,9 @@ Greenfield rebuild from extracted intent rather than a structural port. Mines a
 ### `/modernize-transform <system-dir> <module> <target-stack>`
 Surgical, single-module strangler-fig rewrite. Plans first (HITL gate), then writes characterization tests via `test-engineer`, then an idiomatic target implementation under `modernized/<system>/<module>/`, proves equivalence by running the tests, and produces `TRANSFORMATION_NOTES.md` mapping legacy → modern with deliberate deviations called out. Reviewed by `architecture-critic`.
 
+### `/modernize-status <system-dir>`
+Read-only progress report: artifact inventory with timestamps per workflow stage, staleness flags (e.g. a brief older than the assessment it was built from), secrets-hygiene checks (quarantine file gitignored and never committed), and the single most useful next command. Run it anytime you come back to a modernization after a break.
+
 ### `/modernize-harden <system-dir>`
 Security hardening pass on the **legacy** system: OWASP/CWE scan, dependency CVEs, secrets, injection. Spawns `security-auditor`. Produces `analysis/<system>/SECURITY_FINDINGS.md` ranked Critical / High / Medium / Low and a reviewed `analysis/<system>/security_remediation.patch` with minimal fixes for the Critical/High findings. The patch is reviewed by a second `security-auditor` pass before you see it. **Never edits `legacy/`** — you review and apply the patch yourself when ready, then re-run to verify. Useful as a pre-modernization step when the legacy system will keep running in production during the migration.
 
@@ -85,17 +95,21 @@ This plugin ships commands and agents, but modernization projects benefit from a
       "Edit(modernized/**)"
     ],
     "deny": [
-      "Edit(legacy/**)"
+      "Edit(legacy/**)",
+      "Write(legacy/**)"
     ]
   }
 }
 ```
 
-Adjust `legacy/` and `modernized/` to match your actual layout. The key invariants: `Edit` under `legacy/` is denied, and writes are scoped to `analysis/` (for documents) and `modernized/` (for the new code). Every command in this plugin respects this — `/modernize-harden` writes a patch to `analysis/` rather than editing `legacy/` in place.
+Adjust `legacy/` and `modernized/` to match your actual layout. The key invariants: `Edit`/`Write` under `legacy/` are denied, and writes are scoped to `analysis/` (for documents) and `modernized/` (for the new code). Note this guards the file tools — shell commands that mutate files (`sed -i`, `git apply`) still go through the normal Bash permission prompt, so review those prompts with the same invariant in mind. Every command in this plugin respects this — `/modernize-harden` writes a patch to `analysis/` rather than editing `legacy/` in place.
 
 ## Typical Workflow
 
 ```bash
+# 0. Check the environment is ready (tools, toolchain, source completeness)
+/modernize-preflight billing
+
 # 1. Inventory the legacy system (or sweep a portfolio of them)
 /modernize-assess billing
 
@@ -116,6 +130,9 @@ Adjust `legacy/` and `modernized/` to match your actual layout. The key invarian
 
 # 6. Security-harden the legacy system that's still in production
 /modernize-harden billing
+
+# Anytime: where am I, what's stale, what's next
+/modernize-status billing
 ```
 
 ## License

plugins/code-modernization/agents/architecture-critic.md

@@ -29,12 +29,6 @@ For **transformed code**:
 - Does the test suite actually pin behavior, or just exercise code paths?
 - What would the on-call engineer need at 3am that isn't here?
 
-## Secret handling (mandatory)
-
-When a finding quotes code containing a credential, key, token, or
-connection string, mask the value (`'Pr0d****'`) and cite `file:line` —
-findings get appended verbatim to committed notes files.
-
 ## Output
 
 Findings ranked **Blocker / High / Medium / Nit**. Each with: what, where,

plugins/code-modernization/agents/business-rules-extractor.md

@@ -40,15 +40,6 @@ of the technology, skip it.
    from structure/names), **Low** (ambiguous; needs SME).
 6. If confidence < High, write the exact question an SME must answer.
 
-## Secret handling (mandatory)
-
-Rule parameters sometimes *are* credentials — hardcoded passwords in auth
-checks, API keys in partner-service calls, connection strings in batch
-routines. Record the **rule**, never the **value**: write the parameter as
-`<credential — masked, see file:line>` with at most a 2–4 character
-preview. Rule cards flow into briefs and steering decks; a raw credential
-in a parameter list is a leak.
-
 ## Output format
 
 One "Rule Card" per rule (see the format in the `/modernize-extract-rules`

plugins/code-modernization/agents/legacy-analyst.md

@@ -32,15 +32,6 @@ and explain it in terms a modern engineer can act on.
 - **Note what's missing.** Unhandled error paths, TODO comments, commented-out
   blocks, magic numbers — these are signals about history and risk.
 
-## Secret handling (mandatory)
-
-Legacy code is full of live credentials, and your findings get copied into
-shareable reports. When the evidence for a finding — hardcoded config,
-dead code, debt, an interface payload — includes a credential, API key,
-token, connection string, or private key, **never reproduce the value**.
-Cite `file:line` with a masked preview (`VALUE 'Pr0d****'`,
-`password=****`). The finding is the practice, not the value.
-
 ## Output format
 
 Default to structured markdown: tables for inventories, Mermaid for graphs,

plugins/code-modernization/agents/security-auditor.md

@@ -39,30 +39,7 @@ terminal/screen items don't apply to a SPA. Work through what's relevant:
 
 Use available SAST where it helps (npm audit, pip-audit, grep for known-bad
 patterns) but **read the code** — tools miss logic flaws. Show tool output
-verbatim — except secret values, which you redact (see below) — then add
+verbatim, then add your manual findings.
-your manual findings.
-
-## Secret handling (mandatory)
-
-Legacy codebases routinely contain live production credentials, and your
-findings get pasted into decks, tickets, and committed markdown. Copying a
-secret into a report multiplies the exposure you were hired to find.
-
-When you discover a hardcoded credential, API key, token, connection
-string, or private key:
-
-- **Never write the secret's value into any output** — no finding table,
-  no report, no quoted code excerpt, no echoed tool output. Mask it to the
-  first 2–4 identifying characters plus `****` (`AKIA****`,
-  `postgres://app_user:****@db-prod…`). If a scanner prints a secret,
-  redact it before including the excerpt.
-- Cite `file:line`. The source file is the canonical location — anyone who
-  legitimately needs the value can open it there.
-- State what the credential appears to grant access to (database, queue,
-  cloud account, third-party API) and whether it looks like a production
-  or test credential.
-- Recommend rotation for anything that looks live — exposure in source
-  means it is already compromised, independent of any modernization plan.
 
 ## Reporting standard
 

plugins/code-modernization/agents/test-engineer.md

@@ -28,15 +28,6 @@ someone thinks it should do) so that a rewrite can be proven equivalent.
   `@Disabled("pending RULE-NNN")` / `@pytest.mark.skip` / `it.todo()` — never
   deleted.
 
-## Secret handling (mandatory)
-
-Never copy credential-like literals — passwords, API keys, tokens,
-connection strings — from legacy code into test fixtures. Tests live in
-the deliverable codebase and get committed. Substitute clearly-fake values
-of the same shape and length and note the substitution in a comment.
-Anything a test genuinely needs live (e.g. a real database connection for
-a dual-run harness) is read from an environment variable, never inlined.
-
 ## Output
 
 Idiomatic tests for the requested target stack (JUnit 5 / pytest / Vitest /

plugins/code-modernization/commands/modernize-assess.md

@@ -1,13 +1,11 @@
 ---
 description: Full discovery & portfolio analysis of a legacy system — inventory, complexity, debt, effort estimation
-argument-hint: <system-dir> [--show-secrets] | --portfolio <parent-dir>
+argument-hint: <system-dir> | --portfolio <parent-dir>
 ---
 
 **Mode select.** If `$ARGUMENTS` starts with `--portfolio`, run **Portfolio
 mode** against the directory that follows. Otherwise run **Single-system
-mode** against the system dir. Parse flags positionally-independently:
+mode** against `legacy/$1`.
-`--show-secrets` may appear before or after the system dir — the system
-dir is the first non-flag token.
 
 ---
 
@@ -110,16 +108,12 @@ Spawn three subagents **in parallel**:
 2. **legacy-analyst** — "Identify technical debt in legacy/$1: dead code,
    deprecated APIs, copy-paste duplication, god objects/programs, missing
    error handling, hardcoded config. Return the top 10 findings ranked by
-   remediation value, each with file:line evidence. If evidence contains a
+   remediation value, each with file:line evidence."
-   credential value, mask it per your secret-handling rules — never quote
-   it."
 
 3. **security-auditor** — "Scan legacy/$1 for security vulnerabilities:
    injection, auth weaknesses, hardcoded secrets, vulnerable dependencies,
    missing input validation. Return findings in CWE-tagged table form with
-   file:line evidence and severity. Mask every discovered credential value
+   file:line evidence and severity."
-   per your secret-handling rules — file:line plus a 2–4 character masked
-   preview, never the value itself."
 
 Wait for all three. Synthesize their findings.
 
@@ -147,31 +141,6 @@ need explained.
 
 ## Step 6 — Write the assessment
 
-**Secrets quarantine first.** The assessment gets shared and committed —
-discovered credential values must never appear in it. If the
-security-auditor found any hardcoded credentials:
-
-1. Ensure `analysis/.gitignore` exists and contains the lines
-   `SECRETS.local.md` and `*.local.patch` (create or append as needed —
-   the patch pattern is used by `/modernize-harden`; writing both now
-   means the ignore set is complete from first contact). If the project is a
-   git repo, verify with `git check-ignore -q analysis/$1/SECRETS.local.md`
-   — do not write any findings until the check passes. If there is **no
-   git repo** (check for `.svn`/`.hg`/`CVS` too — a `.gitignore` protects
-   nothing under another VCS): refuse `--show-secrets` and write
-   `SECRETS.local.md` to `~/.modernize/$1/` instead of the project tree,
-   telling the user where it went and why.
-2. Write `SECRETS.local.md`: one row per credential — masked preview,
-   `file:line`, credential type, what it grants access to,
-   production/test guess, rotation recommendation. Only if the user passed
-   `--show-secrets`, add the raw value column here — this file only, never
-   ASSESSMENT.md.
-3. Masking applies to **every section of ASSESSMENT.md**, whichever agent
-   produced the finding — the Technical Debt section quotes hardcoded
-   config; those quotes follow the same masking rule as Security Findings.
-   The Security Findings section adds a one-line pointer:
-   "Credential inventory in SECRETS.local.md (gitignored; not for sharing)."
-
 Create `analysis/$1/ASSESSMENT.md` with these sections:
 - **Executive Summary** (3-4 sentences: what it is, how big, how risky, headline recommendation)
 - **System Inventory** (the scc table + tech fingerprint)

plugins/code-modernization/commands/modernize-brief.md

@@ -8,10 +8,19 @@ single document a steering committee approves and engineering executes.
 
 Target stack: `$2` (if blank, recommend one based on the assessment findings).
 
-Read `analysis/$1/ASSESSMENT.md`, `analysis/$1/TOPOLOGY.html` (and the `.mmd`
+Read `analysis/$1/ASSESSMENT.md`, `analysis/$1/topology.json` (plus the
-files alongside it), and `analysis/$1/BUSINESS_RULES.md` first. If any are
+`.mmd` files alongside it — do NOT read `TOPOLOGY.html`, it's an
-missing, say so and stop — they come from `/modernize-assess`, `/modernize-map`,
+interactive viewer with the data minified inside), and
-and `/modernize-extract-rules` respectively. Run those first.
+`analysis/$1/BUSINESS_RULES.md` first. If any are missing, say so and
+stop — they come from `/modernize-assess`, `/modernize-map`, and
+`/modernize-extract-rules` respectively. Run those first.
+
+**Staleness check:** compare modification times. If any input is newer
+than an existing `MODERNIZATION_BRIEF.md`, the brief is being justifiably
+regenerated; but if an existing brief is newer than all inputs and the
+user re-ran this command anyway, ask what changed. Either way, note the
+input timestamps in the brief's header so reviewers can see what it was
+built from.
 
 ## The Brief
 
@@ -31,28 +40,38 @@ fewest-dependencies first. For each phase:
 - Scope (which legacy modules, which target services)
 - Entry criteria (what must be true to start)
 - Exit criteria (what tests/metrics prove it's done)
-- Estimated effort (person-weeks, derived from COCOMO + complexity data)
+- Estimated effort (person-months, same unit as the assessment's COCOMO
+  figure — convert deliberately if you present weeks)
 - Risk level + top 2 risks + mitigation
 
 Render the phases as a Mermaid `gantt` chart.
 
-### 4. Behavior Contract
+### 4. Business Walkthroughs
+For each persona flow in `analysis/$1/topology.json` (`flows` — produced
+by `/modernize-map`), a short narrative table: persona, what happens in
+business language, which legacy modules implement it today, and which
+phase from §3 replaces each. This is the section non-technical approvers
+actually read — it connects "Phase 2" to "what happens when a customer
+files a claim". If topology.json has no flows, derive 2–3 walkthroughs
+from the entry points and say they need SME confirmation.
+
+### 5. Behavior Contract
 List the **P0 rules** from BUSINESS_RULES.md (the ones tagged `Priority: P0` —
 money, regulatory, data integrity) that MUST be proven equivalent before any
 phase ships. These become the regression suite. Flag any P0 rule with
 Confidence < High as a blocker requiring SME confirmation before its phase
 starts.
 
-### 5. Validation Strategy
+### 6. Validation Strategy
 State which combination applies: characterization tests, contract tests,
 parallel-run / dual-execution diff, property-based tests, manual UAT.
 Justify per phase.
 
-### 6. Open Questions
+### 7. Open Questions
 Anything requiring human/SME decision before Phase 1 starts. Each as a
 checkbox the approver must tick.
 
-### 7. Approval Block
+### 8. Approval Block
 ```
 Approved by: ________________  Date: __________
 Approval covers: Phase 1 only | Full plan
@@ -60,6 +79,7 @@ Approval covers: Phase 1 only | Full plan
 
 ## Present
 
-Enter **plan mode** and present a summary of the brief. Do NOT proceed to any
+Present a summary of the brief and **stop — write nothing further until
-transformation until the user explicitly approves. This gate is the
+the user explicitly approves** (use plan mode if the session supports
-human-in-the-loop control point.
+it). This gate is the human-in-the-loop control point; "no objection" is
+not approval.

plugins/code-modernization/commands/modernize-extract-rules.md

@@ -46,7 +46,7 @@ Merge the three result sets. Deduplicate. For each distinct rule, write a
   When  <trigger>
   Then  <outcome>
   [And  <additional outcome>]
-**Parameters:** <constants, rates, thresholds with their current values — credentials masked: `<credential — masked, see file:line>`>
+**Parameters:** <constants, rates, thresholds with their current values>
 **Edge cases handled:** <list>
 **Suspected defect:** <optional — legacy behavior that looks wrong; decide preserve-vs-fix during transform>
 **Confidence:** High | Medium | Low — <why; if < High, state the exact SME question>

plugins/code-modernization/commands/modernize-harden.md

@@ -1,42 +1,14 @@
 ---
 description: Security vulnerability scan with a reviewable remediation patch — OWASP, CWE, CVE, secrets, injection
-argument-hint: <system-dir> [--show-secrets]
+argument-hint: <system-dir>
 ---
 
-Run a **security hardening pass** on the legacy system: find
+Run a **security hardening pass** on `legacy/$1`: find vulnerabilities, rank
-vulnerabilities, rank them, and produce a reviewable patch for the
+them, and produce a reviewable patch for the critical ones.
-critical ones. Parse arguments flag-independently: the system dir
-(referred to as `$1` below) is the first non-flag token in `$ARGUMENTS`;
-`--show-secrets` may appear anywhere.
 
 This command never edits `legacy/` — it writes findings and a proposed patch
 to `analysis/$1/`. The user reviews and applies (or not).
 
-## Step 0 — Secrets quarantine setup
-
-Findings files get shared, committed, and pasted into decks — discovered
-credential values must never land in them. Before any scanning:
-
-1. Ensure `analysis/.gitignore` exists and contains the lines
-   `SECRETS.local.md` and `*.local.patch`. Create the file or append the
-   missing lines.
-2. If the project is a git repo, verify with
-   `git check-ignore -q analysis/$1/SECRETS.local.md` — if that exits
-   non-zero, fix the ignore rule before proceeding. Do not write any
-   findings until this check passes.
-3. **If there is no git repo** (check for `.svn`/`.hg`/`CVS` too — a
-   `.gitignore` protects nothing under another VCS): refuse
-   `--show-secrets`, and write `SECRETS.local.md` and any `.local.patch`
-   file to `~/.modernize/$1/` instead of the project tree, telling the
-   user where they went and why.
-
-All secret values in every shareable artifact this command produces are
-**masked** (`AKIA****`, `password=****`) and cited by `file:line`. Raw
-values may appear in exactly two places, both gitignored: the
-`*.local.patch` remediation hunks (unavoidably — see Remediate) and, only
-with `--show-secrets`, `SECRETS.local.md`. Never in SECURITY_FINDINGS.md
-or patch commentary.
-
 ## Scan
 
 Spawn the **security-auditor** subagent:
@@ -48,9 +20,7 @@ hardcoded secrets, vulnerable dependency versions, missing input validation,
 path traversal. For each finding return: CWE ID, severity
 (Critical/High/Med/Low), file:line, one-sentence exploit scenario, and
 recommended fix. Run any available SAST tooling (npm audit, pip-audit,
-OWASP dependency-check) and include its raw output. Mask every discovered
+OWASP dependency-check) and include its raw output."
-credential value per your secret-handling rules — file:line plus a 2–4
-character masked preview, never the value itself."
 
 ## Triage
 
@@ -59,50 +29,26 @@ Write `analysis/$1/SECURITY_FINDINGS.md`:
 - Findings table sorted by severity
 - Dependency CVE table (package, installed version, CVE, fixed version)
 
-If any hardcoded credentials were found, also write
-`analysis/$1/SECRETS.local.md` (the gitignored quarantine file from Step 0):
-one row per credential — masked preview, `file:line`, credential type, what
-it appears to grant access to, production/test guess, and a rotation
-recommendation. With `--show-secrets`, append the raw value column here —
-this file only. SECURITY_FINDINGS.md gets a one-line pointer:
-"N hardcoded credentials found — inventory in SECRETS.local.md (gitignored;
-not for sharing)."
-
 ## Remediate
 
 For each **Critical** and **High** finding, draft a minimal, targeted fix.
-Do **not** edit `legacy/` — write fixes as unified diffs with **paths
+Do **not** edit `legacy/` — write all fixes as a single unified diff to
-relative to the project root** (`legacy/$1/...`), applied from the project
+`analysis/$1/security_remediation.patch`, with a comment line above each
-root, with a comment line above each hunk citing the finding ID it
+hunk citing the finding ID it addresses (`# SEC-001: parameterize the query`).
-addresses (`# SEC-001: parameterize the query`).
-
-**Credential findings split into two files.** A diff that removes a
-hardcoded secret necessarily contains the raw value on its `-` and
-context lines — that cannot go in the shareable patch:
-
-- `analysis/$1/security_remediation.patch` (shareable) — every
-  non-credential hunk, plus for each credential finding a comment-only
-  placeholder: `# SEC-NNN: credential remediation — hunk in
-  security_remediation.local.patch (gitignored; not for sharing)`.
-- `analysis/$1/security_remediation.local.patch` (gitignored in Step 0) —
-  the real, applyable hunks for credential findings only.
 
 Add a **Remediation Log** section to SECURITY_FINDINGS.md mapping each
-finding ID → one-line summary of the proposed fix and which patch file
+finding ID → one-line summary of the proposed fix and the patch hunk that
-carries the hunk.
+implements it.
 
 ## Verify
 
-Spawn the **security-auditor** again to **review both patches** against
+Spawn the **security-auditor** again to **review the patch** against the
-the original code:
+original code:
 
-"Review analysis/$1/security_remediation.patch and
+"Review analysis/$1/security_remediation.patch against legacy/$1. For each
-analysis/$1/security_remediation.local.patch against legacy/$1. For each
 hunk: does it fully remediate the cited finding? Does it introduce new
-vulnerabilities or change behavior beyond the fix? Confirm no raw
+vulnerabilities or change behavior beyond the fix? Return one verdict per
-credential values appear anywhere in the shareable patch. Return one
+hunk: RESOLVES / PARTIAL / INTRODUCES-RISK, with a one-line reason."
-verdict per hunk: RESOLVES / PARTIAL / INTRODUCES-RISK, with a one-line
-reason."
 
 Add a **Patch Review** section to SECURITY_FINDINGS.md with the verdicts.
 If any hunk is PARTIAL or INTRODUCES-RISK, revise the patch and re-review.
@@ -111,12 +57,8 @@ If any hunk is PARTIAL or INTRODUCES-RISK, revise the patch and re-review.
 
 Tell the user the artifacts are ready:
 - `analysis/$1/SECURITY_FINDINGS.md` — findings, remediation log, patch review
-- `analysis/$1/security_remediation.patch` — review, then apply **from the
+- `analysis/$1/security_remediation.patch` — review, then apply if appropriate
-  project root**: `git apply analysis/$1/security_remediation.patch`
+  with `git -C legacy/$1 apply ../../analysis/$1/security_remediation.patch`
-  (if `legacy/$1` is a symlink, use `git apply --unsafe-paths` or apply
-  with `patch -p0` from the project root)
-- `analysis/$1/security_remediation.local.patch` — the credential fixes;
-  apply the same way, and rotate the affected credentials regardless
 - Re-run `/modernize-harden $1` after applying to confirm resolution
 
 Suggest: `glow -p analysis/$1/SECURITY_FINDINGS.md`

plugins/code-modernization/commands/modernize-map.md

@@ -55,50 +55,124 @@ re-run and audited. Have it write a machine-readable
 `analysis/$1/topology.json` and print a human summary. Run it; show the
 summary (cap at ~200 lines for very large estates).
 
-## Render
+`topology.json` must follow this schema — it feeds the interactive viewer:
 
-From the extracted data, generate **three Mermaid diagrams** and write them
+```json
-to `analysis/$1/TOPOLOGY.html` as a self-contained page that renders in any
+{
-browser.
+  "system": "<display name>",
-
+  "root": {
-The HTML page must use: dark `#1e1e1e` background, `#d4d4d4` text,
+    "id": "sys", "name": "<system>", "kind": "system",
-`#cc785c` for `<h2>`/accents, `system-ui` font, all CSS **inline** (no
+    "children": [
-external stylesheets). Load Mermaid from a CDN in `<head>`:
+      { "id": "dom:<domain>", "name": "<Domain>", "kind": "domain",
-
+        "children": [
-```html
+          { "id": "<MODULE>", "name": "<MODULE>", "kind": "module",
-<script type="module">
+            "language": "cobol", "loc": 1234, "file": "src/MODULE.cbl" }
-  import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs';
+        ] },
-  mermaid.initialize({ startOnLoad: true, theme: 'dark' });
+      { "id": "dom:data", "name": "Data stores", "kind": "domain",
-</script>
+        "children": [
+          { "id": "ds:<NAME>", "name": "<NAME>", "kind": "datastore" }
+        ] }
+    ]
+  },
+  "edges": [
+    { "source": "<id>", "target": "<id>", "kind": "call" }
+  ],
+  "entryPoints": ["<id>", "..."],
+  "deadEnds": ["<id>", "..."],
+  "observations": ["<architect observation>", "..."],
+  "flows": [
+    { "name": "<business flow>", "persona": "<who experiences it>",
+      "description": "<one sentence, plain language>",
+      "steps": [
+        { "label": "<business-language step>", "nodes": ["<id>", "<id>"] }
+      ] }
+  ]
+}
 ```
 
-Each diagram goes in a `<pre class="mermaid">...</pre>` block. Do **not**
+- Group leaf modules under `domain` containers (use the domains from
-wrap diagrams in markdown ` ``` ` fences inside the HTML.
+  `/modernize-assess` if available). Leaf kinds: `module`, `datastore`,
+  `job`, `screen`. `loc` drives circle size — include it for modules.
+- Edge kinds: `call` (direct), `dispatch` (dynamic/router), `read`,
+  `write`. Every edge endpoint must be a leaf id that exists in the tree.
+- `deadEnds`: the dead-end candidates from the extraction, rendered with
+  a dashed outline in the viewer. Apply the suppression rules above —
+  anything that could be the target of an unresolved dynamic call does
+  NOT belong here; record that uncertainty in `observations` instead.
+- **Datastore ids and names must be logical identifiers** — DD name,
+  dataset name, table/schema name, at most host:port. If the resolved
+  config value is a URL or DSN, strip userinfo and credential query
+  params before it goes anywhere in topology.json: the file gets
+  committed and the viewer displays names verbatim. Never copy raw
+  config values into `observations`.
+- `observations`: 3–7 architect observations — tight coupling clusters,
+  single points of failure, service-extraction candidates, data stores
+  with too many writers, dispatch targets the extraction could not
+  resolve.
+- `flows` is the **persona walkthrough** section — see below.
 
-1. **`graph TD` — Module call graph.** Cluster by domain (use `subgraph`).
+## Persona flows
-   Highlight entry points in a distinct style. Cap at ~40 nodes — if larger,
-   show domain-level with one expanded domain.
 
-2. **`graph LR` — Data lineage.** Programs → data stores.
+Trace **2–4 end-to-end business flows**, each anchored to a persona —
-   Mark read vs write edges.
+the people who experience the system, not the people who maintain it
+(e.g. for a benefits system: the claimant, the caseworker, the auditor;
+for billing: the customer, the billing operator). For each flow:
 
-3. **`flowchart TD` — Critical path.** Trace ONE end-to-end business flow
+- `name` + one-sentence `description` in plain business language —
-   (e.g., "monthly billing run" or "process payment") through every program
+  something a steering committee member relates to ("a claimant files a
-   and data store it touches, in execution order. If production telemetry is
+  weekly claim"), not a data-flow label ("CLM batch ingest").
-   available (see `/modernize-assess` Step 4), annotate each step with its
+- `steps`: 3–8 steps, each with a business-language `label` and the
-   p50/p99 wall-clock.
+  `nodes` (programs + data stores) that implement that step, in
+  execution order.
 
-Also export the three diagrams as standalone `.mmd` files for re-use:
+This is the bridge between the technical map and non-technical
-`analysis/$1/call-graph.mmd`, `analysis/$1/data-lineage.mmd`,
+stakeholders: the same diagram answers "which program does X" for
-`analysis/$1/critical-path.mmd`.
+engineers and "what happens when someone files a claim" for everyone else.
 
-## Annotate
+## Render
 
-Below each `<pre class="mermaid">` block in TOPOLOGY.html, add a `<ul>`
+`analysis/$1/TOPOLOGY.html` is an **interactive map**: a zoomable
-with 3-5 **architect observations**: tight coupling clusters, single
+circle-pack of the whole system (domains as containers, modules sized by
-points of failure, candidates for service extraction, data stores
+LOC) with dependency edges, search, per-node detail sidebar, edge-kind
-touched by too many writers.
+toggles, and a flow-walkthrough mode that plays each persona flow as a
+numbered path. Build it from the template that ships with this plugin —
+do not hand-write the viewer:
+
+```bash
+python3 - "${CLAUDE_PLUGIN_ROOT}/assets/topology-viewer.html" analysis/$1 <<'EOF'
+import json, sys
+tpl_path, out_dir = sys.argv[1], sys.argv[2]
+tpl = open(tpl_path).read()
+marker = "/*__TOPOLOGY_DATA__*/ null"
+assert marker in tpl, f"injection marker not found in {tpl_path}"
+data = json.dumps(json.load(open(f"{out_dir}/topology.json")))
+open(f"{out_dir}/TOPOLOGY.html", "w").write(
+    tpl.replace(marker, "/*__TOPOLOGY_DATA__*/ " + data))
+print(f"wrote {out_dir}/TOPOLOGY.html")
+EOF
+```
+
+The viewer is fully self-contained (the d3 subset it needs is inlined in
+the template) — it works offline and on air-gapped networks. If the
+`python3` invocation fails to find the template,
+`${CLAUDE_PLUGIN_ROOT}` was not substituted — report that rather than
+hand-writing a viewer.
+
+Mermaid stays for **small, exportable** diagrams. Generate standalone
+`.mmd` files for reuse in docs and PRs — but keep each under ~40 edges;
+collapse to domain level if the full graph is bigger (dense Mermaid
+becomes unreadable, which is exactly what the interactive map is for):
+
+- `analysis/$1/call-graph.mmd` — domain-level `graph TD`, entry points
+  highlighted
+- `analysis/$1/data-lineage.mmd` — `graph LR`, programs → data stores,
+  read vs write marked
+- `analysis/$1/critical-path.mmd` — `flowchart TD` of the primary flow
+  from `flows`, annotated with p50/p99 wall-clock if telemetry is
+  available (see `/modernize-assess` Step 4)
 
 ## Present
 
-Tell the user to open `analysis/$1/TOPOLOGY.html` in a browser.
+Tell the user to open `analysis/$1/TOPOLOGY.html` in a browser, and to
+try: search for a module, click it to see its connections, and pick a
+persona flow from the walkthrough dropdown.

plugins/code-modernization/commands/modernize-preflight.md

@@ -0,0 +1,98 @@
+---
+description: Environment readiness check — analysis tools, build toolchain, source completeness, telemetry access
+argument-hint: <system-dir> [target-stack]
+---
+
+Check whether this environment is ready to analyze — and eventually
+transform — `legacy/$1`, and tell the user exactly what to fix before the
+other commands run into it. Modernization sessions fail late and
+confusingly when this isn't done: assessment metrics silently degrade
+without analysis tools, characterization tests can't run without a build
+toolchain, and dependency maps come out wrong when half the source isn't
+in the tree.
+
+Run every check even when an early one fails — the point is one complete
+readiness report, not the first error.
+
+## Check 1 — Detect the stack
+
+Fingerprint `legacy/$1` from file extensions and manifests: languages,
+build system, deployment/config descriptors. This drives which checks
+below apply. Report what was detected and the rough file split.
+
+## Check 2 — Analysis tooling
+
+For each, check availability (`command -v`) and report version, what it's
+used for, and what degrades without it:
+
+| Tool | Used by | Without it |
+|---|---|---|
+| `scc` (or `cloc`) | assess | LOC/complexity fall back to `find`+`wc`; COCOMO estimate gets coarser |
+| `lizard` | assess --portfolio | complexity estimated from decision-keyword counts |
+| `glow` | all | markdown artifacts render as plain text |
+| `delta` | transform | side-by-side diffs fall back to `diff -y` |
+
+Include the platform's install one-liner for anything missing
+(`brew install scc`, `apt install cloc`, `pip install lizard`, …).
+
+## Check 3 — Build toolchain (smoke test, not just presence)
+
+Identify the compiler/interpreter for the detected legacy stack — e.g.
+GnuCOBOL (`cobc`) for COBOL, JDK + Maven/Gradle for Java, `cc`/`make` for
+C, `dotnet` for .NET. Then **prove it works on this codebase**: pick one
+representative source file and run a syntax-only compile
+(`cobc -fsyntax-only`, `javac`, `gcc -fsyntax-only`, …).
+
+A failed smoke test is the most valuable output of this command — report
+the actual error and diagnose it: missing copybook/include path, missing
+dialect flag (`-std=ibm` etc.), fixed vs free format, missing dependency
+jar. These are the errors that otherwise surface mid-`/modernize-transform`
+with much less context.
+
+If the user passed a `[target-stack]`, do the same for it: runtime,
+package manager, test framework (`mvn -v`, `npm -v`, `pytest --version`, …).
+
+## Check 4 — Source completeness
+
+The dependency map is only as good as what's in the tree. Check for the
+detected stack's equivalents of:
+
+- **Referenced-but-missing includes** — copybooks (`COPY X` with no
+  `X.cpy`), headers, imports that resolve nowhere. Count and list the top
+  missing names.
+- **Deployment/config descriptors** — JCL for batch COBOL, CICS CSD
+  definitions, `web.xml`/route configs, cron/scheduler definitions.
+  Without these, entry-point detection and the code↔storage join in
+  `/modernize-map` are guesswork.
+- **Data definitions** — DDL, schemas, copybook record layouts, ORM
+  mappings.
+- **Binary-only artifacts** — load modules, jars, DLLs with no matching
+  source. These become unmappable black boxes; flag them now.
+
+## Check 5 — Optional context
+
+- **Production telemetry** — is an observability/APM MCP server connected,
+  or are batch job logs / runtime exports available? (Enables the runtime
+  overlay in `/modernize-assess` Step 4 and timing annotations in
+  `/modernize-map`.)
+- **Version control history** — is `legacy/$1` under git with meaningful
+  history? (Change-frequency data sharpens risk ranking.)
+
+## Report
+
+Write `analysis/$1/PREFLIGHT.md`: a status table — one row per check,
+status ✅ / ⚠️ / ❌, what was found, and the fix for anything not green —
+followed by a **Ready / Ready-with-gaps / Not ready** verdict per command:
+
+- `assess` + `map` + `extract-rules` — need Checks 1–2 green-ish and
+  Check 4's missing-include count low
+- `brief` — needs only the three discovery artifacts; no tooling
+- `transform` + `reimagine` — additionally need Check 3 green for the
+  **target** stack. A red legacy toolchain downgrades these to
+  Ready-with-gaps, not Not-ready: equivalence testing falls back to
+  recorded traces / golden-master fixtures instead of dual execution
+  (common and expected for CICS/IMS code that has no local runtime)
+- `harden` — needs Check 2 plus any stack-specific SAST tooling found
+
+Print the table in the session too, and end with the single most
+important fix if anything is red.

plugins/code-modernization/commands/modernize-reimagine.md

@@ -3,7 +3,11 @@ description: Multi-agent greenfield rebuild — extract specs from legacy, desig
 argument-hint: <system-dir> <target-vision>
 ---
 
-**Reimagine** `legacy/$1` as: $2
+The first token of `$ARGUMENTS` is the system dir (`$1`); **everything
+after it is the target vision** — it is usually multiple words, so do not
+truncate it to one token. Below, `<vision>` means that full remainder.
+
+**Reimagine** `legacy/$1` as: <vision>
 
 This is not a port — it's a rebuild from extracted intent. The legacy system
 becomes the *specification source*, not the structural template. This command
@@ -19,7 +23,8 @@ Spawn concurrently and show the user that all three are running:
 2. **legacy-analyst** — "Catalog every external interface of legacy/$1:
    inbound (screens, APIs, batch triggers, queues) and outbound (reports,
    files, downstream calls, DB writes). For each: name, direction, payload
-   shape, frequency/SLA if discernible."
+   shape, frequency/SLA if discernible. Mask any credential embedded in
+   endpoints or payload examples per your secret-handling rules."
 
 3. **legacy-analyst** — "Identify the core domain entities in legacy/$1 and
    their relationships. Return as an entity list + Mermaid erDiagram."
@@ -32,6 +37,9 @@ Collect results. Write `analysis/$1/AI_NATIVE_SPEC.md` containing:
 - **Non-functional requirements** inferred from legacy (batch windows, volumes)
 - **Behavior Contract** (the Given/When/Then rules — these are the acceptance tests)
 
+Credential values are masked everywhere in the spec; connection details
+appear as env-var placeholders (`${DATABASE_URL}`), never literals.
+
 ## Phase B — HITL checkpoint #1
 
 Present the spec summary. Ask the user **one focused question**: "Which of
@@ -40,20 +48,21 @@ should deliberately drop?" Wait for the answer. Record it in the spec.
 
 ## Phase C — Architecture (single agent, then critique)
 
-Design the target architecture for "$2":
+Design the target architecture for "<vision>":
 - Mermaid C4 Container diagram
 - Service boundaries with rationale (which rules/entities live where)
 - Technology choices with one-line justification each
 - Data migration approach from legacy stores
 
 Then spawn **architecture-critic**: "Review this proposed architecture for
-$2 against the spec in analysis/$1/AI_NATIVE_SPEC.md. Identify over-engineering,
+<vision> against the spec in analysis/$1/AI_NATIVE_SPEC.md. Identify over-engineering,
 missed requirements, scaling risks, and simpler alternatives." Incorporate
 the critique. Write the result to `analysis/$1/REIMAGINED_ARCHITECTURE.md`.
 
 ## Phase D — HITL checkpoint #2
 
-Enter plan mode. Present the architecture. Wait for approval.
+Present the architecture and **stop — scaffold nothing until the user
+explicitly approves** (use plan mode if the session supports it).
 
 ## Phase E — Parallel scaffolding
 
@@ -65,7 +74,9 @@ in parallel**:
 and AI_NATIVE_SPEC.md. Create: project skeleton, domain model, API stubs
 matching the interface contracts, and **executable acceptance tests** for every
 behavior-contract rule assigned to this service (mark unimplemented ones as
-expected-failure/skip with the rule ID). Write to modernized/$1-reimagined/<service-name>/."
+expected-failure/skip with the rule ID). No credential literal from legacy
+code becomes a test fixture or config default — use fake same-shape values
+and env-var placeholders. Write to modernized/$1-reimagined/<service-name>/."
 
 Show the agents' progress. When all complete, run the acceptance test suites
 and report: total tests, passing (scaffolded behavior), pending (rule IDs
@@ -77,7 +88,9 @@ Write `modernized/$1-reimagined/CLAUDE.md` — the persistent context file for
 the new system, containing: architecture summary, service responsibilities,
 where the spec lives, how to run tests, and the legacy→modern traceability
 map. This file IS the knowledge graph that future agents and engineers will
-load.
+load — and it gets committed: connection details and credentials appear
+only as env-var names with a pointer to where they're provisioned, never
+as values.
 
 Report: services scaffolded, acceptance tests defined, % behaviors with a
 home, location of all artifacts.

plugins/code-modernization/commands/modernize-status.md

@@ -0,0 +1,54 @@
+---
+description: Where am I in the modernization workflow — artifact inventory, staleness, secrets hygiene, next step
+argument-hint: <system-dir>
+---
+
+Report where the modernization of `$1` stands, in one screen. This is a
+read-only command — inspect, never modify.
+
+## 1 — Artifact inventory
+
+Check `analysis/$1/` and `modernized/$1*/` and build a table — one row per
+workflow stage, with the artifact's presence and modification time:
+
+| Stage | Artifacts |
+|---|---|
+| preflight | `PREFLIGHT.md` |
+| assess | `ASSESSMENT.md`, `ARCHITECTURE.mmd` |
+| map | `topology.json`, `TOPOLOGY.html`, `*.mmd`, `extract_topology.*` |
+| extract-rules | `BUSINESS_RULES.md`, `DATA_OBJECTS.md` |
+| brief | `MODERNIZATION_BRIEF.md` (note whether the approval block is signed) |
+| harden | `SECURITY_FINDINGS.md`, `security_remediation.patch` |
+| transform / reimagine | each `modernized/$1*/<module>/` dir — note test presence and whether `TRANSFORMATION_NOTES.md` exists |
+
+## 2 — Staleness
+
+Flag any artifact older than an upstream artifact it derives from:
+
+- `MODERNIZATION_BRIEF.md` older than `ASSESSMENT.md`, `topology.json`,
+  or `BUSINESS_RULES.md` → the brief no longer reflects discovery;
+  recommend re-running `/modernize-brief`.
+- `TOPOLOGY.html` older than `topology.json` → re-run the injection step
+  from `/modernize-map`.
+- Any `TRANSFORMATION_NOTES.md` older than `BUSINESS_RULES.md` → the
+  module may not implement the latest rule set; list which.
+
+## 3 — Secrets hygiene
+
+- Does `analysis/.gitignore` exist and cover `SECRETS.local.md` /
+  `*.local.patch`? (`git check-ignore` when in a git repo.)
+- If `SECRETS.local.md` exists: confirm it is NOT tracked
+  (`git ls-files --error-unmatch`, expect failure) and has never been
+  committed (`git log --all --oneline -- <path>`, expect empty). If
+  either check fails, say so prominently and recommend rotation plus
+  history scrubbing.
+
+## 4 — Verdict
+
+End with three lines:
+- **Where you are** — the furthest completed stage and roughly how much
+  of the system it covers (e.g. "mapped 100%, 2 of 14 modules
+  transformed").
+- **What's stale** — or "nothing".
+- **Next command** — the single most useful next step, with a one-line
+  reason.

plugins/code-modernization/commands/modernize-transform.md

@@ -9,10 +9,37 @@ equivalence.
 This is a surgical, single-module transformation — one vertical slice of the
 strangler fig. Output goes to `modernized/$1/$2/`.
 
-## Step 0 — Plan (HITL gate)
+## Step 0a — Toolchain check (fail fast on target, adapt on legacy)
+
+Verify the build environment **before** planning, not when the tests
+first run:
+
+- **Target stack ($3) — required.** Runtime, package manager, and test
+  framework all respond (`java -version` + `mvn -v`, `node -v` + `npm -v`,
+  `python3 -V` + `pytest --version`, …). If any are missing, stop and
+  report what to install — the new code and its tests cannot run without
+  them, so a plan gate now would just defer the failure an hour. Suggest
+  `/modernize-preflight $1 $3` for the full readiness report.
+- **Legacy stack — advisory, never a blocker.** Try a syntax-only compile
+  of the module being transformed (e.g. `cobc -fsyntax-only`). Legacy
+  code often *cannot* build locally by nature, not by misconfiguration —
+  CICS/IMS programs have no local translator, and the real runtime may be
+  a mainframe you don't have. A failed or impossible legacy compile does
+  **not** stop the transform; it changes the equivalence strategy:
+  - dual-execution proof is off the table — characterization tests
+    assert against **recorded traces / golden-master fixtures** (real
+    production outputs, captured reports/screens, SME-confirmed
+    examples) instead of live legacy runs
+  - say so explicitly in the Step 0b plan and later in
+    TRANSFORMATION_NOTES.md ("equivalence is trace-based; legacy was not
+    executable in this environment"), so reviewers know the strength of
+    the proof they're approving
+
+## Step 0b — Plan (HITL gate)
 
 Read the source module and any business rules in `analysis/$1/BUSINESS_RULES.md`
-that reference it. Then **enter plan mode** and present:
+that reference it. Then present the plan and **stop — write no code until
+the user explicitly approves** (use plan mode if the session supports it):
 - Which source files are in scope
 - The target module structure (packages/classes/files you'll create)
 - Which business rules / behaviors this module implements
@@ -30,7 +57,9 @@ identify every observable behavior, and encode each as a test case with
 concrete input → expected output pairs derived from the legacy logic.
 Target framework: <appropriate for $3>. Write to
 `modernized/$1/$2/src/test/`. These tests define 'done' — the new code
-must pass all of them."
+must pass all of them. Follow your secret-handling rules: no credential
+literal from legacy code becomes a fixture; substitute fake same-shape
+values and read anything genuinely live from environment variables."
 
 Show the user the test file. Get a 👍 before proceeding.
 
@@ -68,6 +97,10 @@ Then show a visual diff of one representative behavior, legacy vs modern:
 ```bash
 delta --side-by-side <(sed -n '<lines>p' legacy/$1/<file>) modernized/$1/$2/src/main/<file>
 ```
+(Fall back to `diff -y --width=160` if `delta` isn't installed.) Never
+pick a credential-bearing line range for this diff, and mask any
+credential-like literal quoted in TRANSFORMATION_NOTES.md — the notes
+live in `modernized/` and get committed.
 
 ## Step 5 — Architecture review