Imported from wwa-lab/legacy-spec-factory (.codex/skills/legacy-step-contract/SKILL.md). Install upstream with npx skills add wwa-lab/legacy-spec-factory --skill legacy-step-contract. Copyright stays with the author.

Legacy Step Contract

Skill Card

Field	Notes
Problem solved	Defines the shared INPUT -> EXECUTION -> OUTPUT -> VALIDATION contract every Legacy Spec Factory step must follow.
Input	A skill, step design, or artifact that needs contract shape, quality gates, and validation semantics.
Output	Contract guidance for readiness, execution rules, output status, validation expectations, and workflow state write-back.
Core prompt strategy	Make stage boundaries explicit, define allowed inference and stop conditions, and keep status transitions auditable.
Upstream skill	None; this is the governance baseline for the skill family.
Downstream consumer	All Legacy Spec Factory skills and `legacy-step-validator`.
Validation standard	Each step declares inputs, execution rules, outputs, validation result semantics, and blocked/warning handling.
Known risk	Treating the contract as prose guidance only instead of a required quality gate.
Practical example	Use the contract to add a Step Contract section to a new data-model analysis skill before accepting it.

Purpose

Every step in the Legacy Spec Factory reverse chain follows the same shape:

INPUT  →  EXECUTION  →  OUTPUT  →  VALIDATION

This skill formalizes that shape into a portable Step Contract so that authors, agents, and reviewers share one vocabulary across:

legacy-ibmi-inventory
legacy-ibmi-program-analyzer
legacy-ibmi-flow-analyzer
legacy-ibmi-module-analyzer
legacy-spec-writer
legacy-spec-reviewer (planned)
forward SDLC handoff (docs/forward-sdlc-contract.md)
future Layer 1 families (legacy-cobol-*, legacy-mainframe-*)

The skill defines (or reviews) Step Contract blocks and the Step Validation Report shape. legacy-step-validator applies this contract to completed artifacts and emits filled validation reports under 06_quality/. This skill does not produce inventory, program analyses, specs, or business findings.

When to Use

Trigger on any of these signals:

An author or agent is designing a new pipeline step and needs a contract to anchor it.
A step is about to execute and the runner wants to confirm its inputs and stop conditions before producing output.
A step has produced output and a reviewer wants a structured pass / warn / block decision before downstream handoff.
A skill review (docs/skill-review-gate.md) wants to verify that a skill's workflow and output contract are explicit and enforceable.
An orchestrator (legacy-modernization-orchestrator) needs to surface why a gate is blocked in a uniform shape.

When NOT to Use

Do not trigger when:

The user wants the business artifact itself (inventory, program analysis, flow, module, spec, review). Route to the dedicated skill.
The user wants SME interviews, capability discovery, or rule mining.
The task is forward SDLC code generation. Use wwa-lab/build-agent-skill.
The task is platform-specific extraction. Use the matching Layer 1 skill.

This skill is a contract layer. If you find yourself producing IBM i facts, you are in the wrong skill.

Role

You are the contract author / contract checker for one pipeline step.

You must:

restate the step's INPUT, EXECUTION, OUTPUT, and VALIDATION explicitly
distinguish mechanical validation, AI semantic review, and SME / human approval — they are not interchangeable
produce a compact validation result with one of three statuses
surface unresolved items by category so the next skill (or human) can act
refuse to infer step content the upstream artifact does not contain

You must not:

invent inputs the step does not actually have
mark a step pass because it "looks right" — pass requires the validation evidence enumerated below
collapse SME approval into AI semantic review

The Step Contract

A Step Contract has four mandatory sections. See references/step-contract.md for the full field-level specification, defaults, and worked examples.

1. INPUT

Required fields:

step_id — stable ID for this step instance (STEP-<SLUG>-<NNN> per docs/id-conventions.md)
skill — the skill or doc that executes the step (e.g. legacy-ibmi-program-analyzer)
prerequisite_artifacts — list of upstream artifacts with their required status (e.g. inventory.yaml at approved or approved_with_non_blocking_tbd)
prerequisite_gates — gates that must already be passing (Evidence Authorization, Inventory Completeness, Evidence Approval, Forward Handoff)
evidence_scope — the EV-* IDs and OBJ-* IDs that are in scope, plus authorization fields (sensitivity, source_path_verified, redaction_required, redaction_status) that must already be resolved
sme_availability — whether an SME owner is required for this step and the capability slug they own
assumptions_recorded — assumptions the runner is allowed to make explicitly, never silently

Stop and refuse to execute the step if:

any prerequisite artifact is missing or below the required status
any prerequisite gate is blocked
any evidence has sensitivity: unknown, lacks source-path authorization, or requires redaction without an approval record
SME is required by the step but not assigned

2. EXECUTION

Required fields:

procedure — pointer to the workflow inside the executing skill (SKILL.md section or references/ file). The Step Contract does not re-describe the procedure; it cites it.
inputs_to_outputs_mapping — which input fields drive which output fields
tools_allowed — what the executing skill is allowed to do (read source, read DDS, call sub-skill, call SME, etc.)
tools_forbidden — what the step must refuse (e.g. generating Java, inventing object names, reading unauthorized evidence)
decision_points — any branch where the step must choose between alternatives, plus how that choice is recorded

Execution rules:

The step writes its own output. The Step Contract does not.
The step preserves IDs; it does not renumber on re-execution.
The step records every assumption inline with the artifact it produces.
The step treats rendered previews, browser views, image/PDF previews, Mermaid previews, spreadsheet previews, and HTML openings as optional review aids. They must not be automatic completion gates unless the executing skill explicitly says so or the user asks for visual inspection.
After primary artifacts, validation status, and workflow-state write-back are recorded, the step stops. It does not keep polling workflow status, re-reading changed files, or reopening previews. Re-entry is allowed only when a deterministic validator finding names a concrete artifact to fix.

3. OUTPUT

Required fields:

primary_artifacts — file paths, suggested filenames, and the schema or template each one must follow
id_namespaces — which ID prefixes the step is allowed to mint (BEH-*, BR-*, BR-* seeds, STEP-*, TBD-*, etc.) per docs/id-conventions.md
cross_references — what the output must link back to (every claim links to one or more EV-*; every BR-* links to BEH-* and EV-*)
status_field — the lifecycle field the artifact carries (draft, delivery_draft, in_review, approved, approved_with_non_blocking_tbd, blocked, rejected, retired; poc_draft is allowed only for internal POC artifacts)
non_outputs — what the step is not allowed to produce (e.g. a flow analyzer does not produce capability specs)

4. VALIDATION

Validation has three distinct layers, in order. None substitutes for another.

4a. Mechanical Validation

What can be checked by a script, a schema, or a deterministic linter:

required files exist at expected paths
YAML / JSON validates against schemas/spec.schema.yaml (or the relevant schema)
all referenced IDs resolve (no dangling EV-*, BR-*, OBJ-*)
ID prefixes match docs/id-conventions.md
every claim has at least one linked evidence item
every sensitivity: unknown is resolved and every evidence item has either source-path authorization or completed required redaction
review status fields are in the allowed enum

Mechanical validation must be reproducible. If it depends on judgment, move it to AI semantic review.

4b. AI Semantic Review

What an LLM (or careful reviewer) can check by reading the artifact against the upstream evidence:

the artifact's claims are consistent with linked evidence
knowledge type (observed_behavior / inferred_business_rule / modernization_decision / unknown_tbd) matches the kind of claim made
evidence strength is not overstated (no weakly_inferred posing as confirmed_from_code)
no invented IBM i facts (object names, fields, jobs, screens, reports)
no scope creep into a different capability
TBDs are explicit, not hidden inside prose

AI semantic review must call out uncertainty rather than smooth it over.

4c. SME / Human Approval

What only a domain expert can decide:

whether an inferred rule is actually a business rule
whether a behavior the code shows is intentional or a bug
whether a modernization decision is acceptable
whether a TBD is blocking or non-blocking
whether the step's output is safe to promote to approved

SME approval is a control point, not a rubber stamp. The Step Validation Report must record the SME's name (or role), the date, and the specific decision against the specific IDs.

Compact Validation Result

Every step run must produce one of three statuses:

Status	Meaning	Downstream Effect
`pass`	Mechanical validation passes, AI semantic review finds no blocking issues, and (if applicable for this step) SME approval is recorded	The step's output may be consumed by the next step
`pass_with_warnings`	Mechanical validation passes; AI semantic review found non-blocking issues OR SME approved with non-blocking TBDs	Output may be consumed downstream, but the carried warnings must travel with it
`blocked`	At least one mechanical, semantic, or SME blocker exists	Output must not be consumed downstream until the blocker is resolved or explicitly waived by an SME

A step is not allowed to self-promote past blocked without resolving or explicitly waiving the blocker.

pass_with_warnings is for non-blocking items only; if you find yourself adding a "warning" that is actually critical, the status is blocked.

Internal POC Draft Mode

For internal POC validation, distinguish draft production from approval/downstream consumption:

Evidence authorization, known sensitivity, and redaction safety remain non-bypassable hard gates.
Missing completeness evidence (OCR, Markdown, object maps, program analyses, flow analyses, SME owner, source eligibility, or validation runtime) should become pass_with_warnings for draft-only artifacts when the user explicitly requests POC output and every weak claim is labeled low-confidence or TBD-*.
The same missing evidence remains blocked for approval, spec writing, SDD handoff, production use, or any claim that pretends to be confirmed.
A POC draft must carry an explicit status such as poc_draft, a limitation note, and approval/spec blockers in the review or traceability artifact.

This mode is a controlled acceleration path, not a waiver of evidence safety or traceability.

Daily Delivery Mode

For day-to-day BRD delivery, distinguish delivery iteration acceptance from formal baseline approval:

Evidence authorization, known sensitivity, and redaction safety remain non-bypassable hard gates.
The runner should continue through context, inventory, program, flow, module, data-model, and BRD drafting without stopping for separate human approval at each intermediate artifact when mechanical and semantic validation have no blocking findings.
A program-flow seed such as Program A -> Program B -> Program C may start the chain as scope input. It is not proof of parameter semantics, data mutation, trigger model, commit boundaries, or business meaning; those must be derived from source/evidence or carried as TBD-*.
Missing supplemental evidence, SME availability windows, or non-critical analyzer gaps should become warnings, TBD-*, or daily review questions when they do not alter high-risk business meaning.
Critical contradictions, unresolved source authorization, scope ambiguity, and high-risk business-rule uncertainty remain blocked until resolved or explicitly waived by the accountable owner.
A daily BRD must carry mode: daily_delivery, status: delivery_draft, evidence_mode: daily_delivery, and review_policy: exception_only.
Final review may record accepted_for_daily_delivery; this is not equivalent to approved and does not pass spec-writing, SDD handoff, audit-baseline, or knowledge-publication gates.

This mode reduces approval frequency; it does not weaken traceability or allow a draft artifact to masquerade as an approved baseline.

Surfacing Unresolved Items

Every Step Validation Report must categorize unresolved items into:

Category	Definition	Typical Resolver
`missing_inputs`	A required upstream artifact, status, or gate is absent	Run or finish the upstream skill / gate
`evidence_gaps`	An artifact reference exists but the evidence itself is missing, unreadable, or unauthorized	Source owner provides, authorizes, redacts, or formally waives the artifact
`contradictory_evidence`	Two or more evidence items disagree about behavior, rule, or field shape	SME decides which evidence holds; record the decision with a `DEC-*`
`sme_questions`	A judgment-only question that only a domain expert can answer	SME records the answer in the artifact's review section
`downstream_handoff_blockers`	An item that does not block this step's draft but will block the next step	Resolve before next step, or mark non-blocking with SME approval and forward

Each item must carry:

a stable ID (TBD-<SLUG>-<NNN>)
the category above
the artifact(s) it points to
the resolver role
whether it is blocking the current step, the next step, or both

Do not mix these categories together in a single bucket — that hides which role can resolve which item.

How the Contract Applies to Each Step

See references/step-contract.md for the full matrix. Summary:

Step	Skill	Primary Input	Primary Output	SME Required At Pass?
Inventory	`legacy-ibmi-inventory`	approved evidence manifest with source-path authorization or required redaction	`inventory.yaml`, `object-map.md`	Yes for inventory completion — `sme_review.decision` must be `approved` or `approved_with_non_blocking_tbd`; no for starting developer-led inventory
Program analysis	`legacy-ibmi-program-analyzer`	program source; approved inventory required for `chain_ready`, optional reference packs for field/message/control meanings, optional inventory for `standalone_exploratory` inspection	`program-analysis.md` per program	Recommended; required if program affects money, inventory, compliance, or customer status
Flow analysis	`legacy-ibmi-flow-analyzer`	approved program analyses for chain	`flow-<FLOW-SLUG>.md`	Recommended; required if cross-program rule emerges
Module analysis	`legacy-ibmi-module-analyzer`	approved flow analyses + module scope notes	focused module package	Yes — for module-level capability seeds and BR-* seeds
Spec writing	`legacy-spec-writer`	approved module + flow + program + inventory	`spec.yaml`, `spec.md`, `spec-review.md`, `traceability.md`	Yes — `business_rules[*].review_status = approved` requires SME
Spec review	`legacy-spec-reviewer` (planned)	drafted spec	`review-report.md`	Yes — SME sign-off transitions spec from `in_review` to `approved`
Forward SDLC handoff	doc-only gate (`docs/forward-sdlc-contract.md`)	approved spec	handoff bundle to `wwa-lab/build-agent-skill`	Yes — gate is the SME-recognized contract

The Step Contract block format is identical across all rows; only the field values change. That is the point — one contract shape, every step.

Workflow

A. Authoring a Step Contract

Identify the step (inventory, program analysis, flow, module, spec, etc.).
Copy templates/step-contract-block.md.
Fill INPUT, EXECUTION, OUTPUT, VALIDATION with the values for that step instance. Do not invent fields — use references/step-contract.md.
Cite the executing skill's procedure; do not re-describe it.
Record the SME role expected at pass, even if pass is not yet reached.

B. Pre-Execution Check

Confirm every INPUT field has a concrete value.
Score input readiness using docs/input-readiness-rubric.md: identify hard blockers, minimum-pass inputs, optional missing inputs, and quality boosters before execution.
Confirm prerequisite gates are passing (do not assume).
If any INPUT field cannot be resolved, mark the step blocked immediately and surface the unresolved item under the correct category.
Only when INPUT is at least minimum_pass, hand control to the executing skill. A minimum_pass score may proceed with warnings; a blocked score must not.

C. Post-Execution Validation

Run mechanical validation (4a). If anything fails, status is blocked.
Run AI semantic review (4b). Distinguish blocking findings from non-blocking.
Verify SME approval (4c) if the step requires it. SME absence at a step that needs SME is itself a blocker.
Apply legacy-step-validator to emit a templates/step-validation-report.md shaped report with status, findings by layer, and unresolved items by category.
If pass_with_warnings, the warnings travel with the artifact to the next step. Do not silently drop them.

D. Reporting to the Orchestrator

When legacy-modernization-orchestrator asks "can this step's output be consumed downstream?", answer in this exact shape:

status: pass | pass_with_warnings | blocked
step_id: STEP-<SLUG>-<NNN>
blocking_items: [TBD-..., TBD-...]
warnings: [TBD-...]
sme_decision: approved | approved_with_non_blocking_tbd | pending | blocked | not_required
downstream_next_step: <skill-name | doc-path | none>
remediation_step: <skill-name | doc-path | none>

Anything more verbose belongs in the full Step Validation Report.

Workflow State Write-Back (history only)

This is a meta / contract skill — it defines the INPUT → EXECUTION → OUTPUT → VALIDATION contract that other skills follow. It rarely runs standalone. When it does, it produces a contract-conformance report and does NOT mutate capabilities[].stage_id or current_focus.

After a run, append one history[] entry to <project-root>/workflow-state.yaml per docs/workflow-state-contract.md:

history:
  - at: <ISO 8601>
    skill: legacy-step-contract
    capability_id: <CAP-* from current_focus, or null>
    stage_after: <UNCHANGED stage_id, or null>
    artifact: <path to the conformance report, or null>
    note: "contract conformance check — <step-id>: pass | warnings | blocked"

Also overwrite project.last_updated_at / project.last_updated_by.

If workflow-state.yaml does not exist, this skill does NOT create it.

Anti-Hallucination Rules

Do not invent IBM i object names, field names, program names, job names, or capability slugs. The Step Contract carries IDs; it does not mint legacy facts.
Do not promote a status. Only the executing skill plus its SME may promote an artifact from draft to in_review to approved.
Do not collapse layers. Mechanical, semantic, and SME are not interchangeable.
Do not paper over unknown_tbd. If evidence is missing, the answer is a TBD-* plus a category, not a confident summary.
Do not approve based on confidence. high confidence does not bypass SME for business-critical claims (see docs/evidence-and-knowledge-taxonomy.md).
Do not treat SME review as a rubber stamp. SME approval must name the SME, the date, and the specific IDs approved.

Quality Checklist

Before emitting a Step Contract block, or before reviewing a Step Validation Report emitted by legacy-step-validator, confirm:

All four sections (INPUT, EXECUTION, OUTPUT, VALIDATION) are present
Required fields per references/step-contract.md are filled
Mechanical, AI semantic, and SME approval are written as separate checks
Status is pass, pass_with_warnings, or blocked — no third option
Every unresolved item carries an ID, a category, an artifact pointer, and a resolver
No IBM i facts have been invented; all object names come from upstream artifacts
SME role is named when SME approval is required
Cross-references (EV-*, BR-*, OBJ-*, STEP-*) resolve

Relationship to Other Legacy Spec Factory Skills

legacy-modernization-orchestrator consumes the compact validation result format to decide routing and gate state. The orchestrator does not re-derive validation; it reads reports emitted by legacy-step-validator.
Layer 1 skills (legacy-ibmi-inventory, legacy-ibmi-program-analyzer, legacy-ibmi-flow-analyzer, legacy-ibmi-module-analyzer) and Layer 2 skills (legacy-spec-writer, future legacy-spec-reviewer) each have their own output contract; this skill wraps a portable Step Contract around them so that gates, reviews, and handoffs share one vocabulary.
docs/skill-review-gate.md uses the same vocabulary when scoring a skill's workflow completeness and output contract.
docs/forward-sdlc-contract.md is itself a Step Contract for the final crossing into wwa-lab/build-agent-skill.

This skill does not replace any of the above. It gives them a shared shape.

Runtime Portability

The canonical skill source lives under:

skills/legacy-step-contract/SKILL.md
skills/legacy-step-contract/references/step-contract.md
skills/legacy-step-contract/templates/step-contract-block.md
skills/legacy-step-contract/templates/step-validation-report.md
skills/legacy-step-contract/examples/inventory-pass/

Runtime copies may be synced to:

.claude/skills/legacy-step-contract/
.opencode/skills/legacy-step-contract/
.agents/skills/legacy-step-contract/
.codex/skills/legacy-step-contract/

From the repository root, use scripts/sync-skills.sh to create or check runtime copies. Do not edit adapter copies directly.

No runtime-specific assumptions are baked into this canonical source.

Version History

v0.1.2 (2026-05-29): Renamed scattered-context Step Contract wording so upstream context notes are not confused with canonical module-analysis artifacts.
v0.1.3 (2026-05-31): Added the global artifact-preview and stop-after-writeback completion boundary so steps do not keep processing after outputs, validation status, and workflow-state write-back are recorded.
v0.1.1 (2026-05-14): Added worked inventory-pass Step Contract and Step Validation Report examples. Reconciled compact validation result fields (downstream_next_step, remediation_step) and clarified that legacy-step-validator emits filled reports. Runtime smoke tests passed in Codex CLI (gpt-5.4-mini), Claude Code (haiku), and OpenCode (opencode/minimax-m2.5-free).
v0.1.0 (2026-05-14): Initial Step Contract skill. Formalizes INPUT → EXECUTION → OUTPUT → VALIDATION across all reverse-chain steps. Distinguishes mechanical validation, AI semantic review, and SME approval. Defines compact validation result (pass, pass_with_warnings, blocked) and the five unresolved-item categories. Portable across Codex, Claude Code, and OpenCode.

legacy-step-contract

About

Legacy Step Contract

Skill Card

Purpose

When to Use

When NOT to Use

Role

The Step Contract

1. INPUT

2. EXECUTION

3. OUTPUT

4. VALIDATION

4a. Mechanical Validation

4b. AI Semantic Review

4c. SME / Human Approval

Compact Validation Result

Internal POC Draft Mode

Daily Delivery Mode

Surfacing Unresolved Items

How the Contract Applies to Each Step

Workflow

A. Authoring a Step Contract

B. Pre-Execution Check

C. Post-Execution Validation

D. Reporting to the Orchestrator

Workflow State Write-Back (history only)

Anti-Hallucination Rules

Quality Checklist

Relationship to Other Legacy Spec Factory Skills

Runtime Portability

Version History

Use it

Manifest

Reviews