# ConfigKit Consolidation Toward 1.0

Status: selected target state; implementation pending. This document defines the
refactor's scope and rationale; it does not authorize a release. The scope
questions are settled. The [implementation plan](implementation.md) owns the
concrete steps, sequencing, and implementation progress.

## Purpose

Consolidate the machinery introduced by recent import, collection, inheritance,
and discovery work so ConfigKit is easier to understand, maintain, and adopt
before its public contracts become stable. Success means fewer independently
maintained paths through the same behavior, clearer state ownership, and concise
consumer workflows. Reducing a function's line count is useful only when it
serves those outcomes.

The review considered public API consolidation as well as internal extraction.
The settled public direction retains the existing simple and layered loading APIs,
consolidates their private translation and acquisition machinery, and removes
unused reverse inspection conversions. No public signature or configuration
semantic change is planned in this effort. This is an assessment of the reviewed
consumer workflows, not a requirement to preserve every beta API in perpetuity.

## Evidence And Baseline

Reviewed worktree: `c9574ef`, immediately after the `v0.10.0` release at `5959537`.
This document replaces the earlier `complexity.md` roadmap and `remediation.md`
audit record. Their recommendations and relevant evidence are incorporated here;
the original documents remain available in Git history:

```sh
git show fbaaaf1:docs/roadmap/complexity.md
git show fbaaaf1:docs/roadmap/remediation.md
```

The earlier roadmap reviewed `7a83704f43ef9870db33661231cdff5d6ee502f7`, before
discovery. The audit reviewed `5959537d1adc2516e7f7e8881df72b707ec48c3f`, including
implemented discovery. The consolidation review checked their recommendations
against that newer baseline and also considered the public API.

This review inspected the current public load/input/discovery declarations and
maintained consumer examples, the shared request executor and acquisition flow,
import parsing and selection, inheritance execution, reflective projection and
cloning, schema field construction, and filesystem-context derivation. Graph
caller traces and text-reference checks confirmed the unused reverse conversion
chain. This was source review, not a new runtime correctness or performance audit.
Neither this review nor the audit established a runtime correctness defect.

### Audit Measurements

The audit refreshed the codebase-memory graph and used function size, cognitive
complexity, branch counts, and parameter counts to rank candidates for source
inspection. It indexed 901 non-test functions/methods and 928 test-file
declarations. Its fast index excludes examples, documentation, and scripts; a
tracked-file inventory covered those separately. Standalone `gocyclo`, `gocognit`,
`scc`, and `cloc` tools were unavailable.

These are the graph tool's reported measurements at the audited revision.
Function spans include comments and blank lines. The scores support relative
triage; they are not standardized acceptance thresholds or evidence of a defect.

| Function | Source | Lines | Cognitive score |
| --- | --- | ---: | ---: |
| `valueOperation.project` | [projection.go](../../internal/engine/projection.go) | 195 | 174 |
| `parseImportDeclarationSpec` | [import_spec.go](../../internal/engine/import_spec.go) | 127 | 129 |
| `valueOperation.clone` | [clone.go](../../internal/engine/clone.go) | 130 | 104 |
| `schemaBuilder.describeFields` | [schema.go](../../internal/engine/schema.go) | 99 | 100 |
| `assembleBaseInputTrackedForRole` | [load_input.go](../../internal/engine/load_input.go) | 188 | 96 |
| `selectDirectoryImportCandidates` | [import_selection.go](../../internal/engine/import_selection.go) | 154 | 96 |
| `valueBuilder.build` | [value.go](../../internal/engine/value.go) | 104 | 93 |
| `decodeValue` | [decode.go](../../internal/engine/decode.go) | 115 | 85 |
| `applyInheritanceScopeTemplates` | [inheritance_schedule.go](../../internal/engine/inheritance_schedule.go) | 219 | 75 |
| `contextsForAcquiredSources` | [source_context.go](../../internal/engine/source_context.go) | 102 | 72 |

At that revision, the engine contained 88 production Go files and approximately
20,144 physical lines; the root facade contained 16 files and 1,861 lines.
`imports.go` was the largest production file at 1,195 lines. These measurements
locate concentrated responsibilities. They do not establish a need for more
packages or make the smaller document/YAML visitors and explicit facade
conversions maintenance defects.

### Findings And Recommended Treatment

The finding numbers below preserve the audit's identifiers. The selected work
remains unimplemented; the cloning portion of finding 3 is deferred to future
work. Retiring the original documents does not mark their findings implemented.

| Audit finding | Maintenance priority | Assessment and recommended treatment |
| --- | --- | --- |
| 1. Import entry points and responsibilities | Higher | Main refactor. Include shared acquisition normalization, import-default ownership, declaration parsing, and directory admission. |
| 2. Shared inheritance executor | Higher | Main refactor. Expose meaningful phases and explicit combination results while retaining one executor. |
| 3. Projection and cloning | Higher for projection; cloning deferred | Main refactor for projection. Clone traversal review is tracked separately in [future.md](future.md#4-clone-traversal-review). |
| 4. Schema field discovery and inline assembly | Medium | Include a focused refactor coordinated with projection. Keep one schema builder and its two descriptor views. |
| 5. Resolved filesystem context | Medium | Include alongside acquisition work. Reuse resolved facts without merging resource lifetimes or changing validation timing. |
| 6. Unused reverse inspection conversions | Small, independently reviewable cleanup | Include in the root facade and engine. Retain useful forward-conversion and detached-result coverage. |

Findings 1–3 confirm the earlier roadmap's main opportunities; findings 4–6 add
focused work. The following sections own their rationale and intended changes.
Implementation and validation will establish completion of the selected work;
the deferred clone review retains its separate disposition.

Completed correctness and algorithmic remediations remain part of the baseline,
including sequence records preserved at `ea46001:docs/roadmap/remediation.md`
and discovery records preserved at `0369111:docs/roadmap/remediation.md`.
Item-scope application matching and inheritance policy localization are examples
of completed corrections that overlap this work and whose regressions should
remain protected.

The [architecture policy](../policy/architecture.md),
[configuration contract](../config.md), and exported declaration comments own
existing constraints and behavior. The
[component overview](../internal/overview.md) and
[import internals](../internal/imports.md) locate implementation responsibilities.

## Consumer-Facing Target

### Keep Simple Loading Simple And Advanced Inputs Explicit

The current APIs already provide progressive setup:

- A simple consumer calls `Load[Config](File(path))`.
- A consumer with defaults, imports, or resolution supplies `Options[Config]`.
- Explicit discovery produces an ordinary `Source`, so it uses the same loading
  call and lifecycle.
- A layered consumer supplies an `Input` and `LayeredOptions[Config]`, with
  `Underlay.Inputs` distinguishing strict peers from precedence tiers.

The two loading functions already converge on `loadRequest` and
`executeLoadRequest`. Their public differences have meaning: ordinary options
include the one input's controls; layered loading has per-input controls and a
separate overlay filesystem. Ordinary overlay context follows its selected
source, whereas layered overlay context is independently specified. These are
observable conventions, not interchangeable forwarding spellings.

**Decision (OQ-1, settled):** retain `Load`, `LoadLayered`, `Options`, `LayeredOptions`,
`Input`, and `Underlay`. Remove repeated translation and option reconstruction
behind them. Keep common application rules in `Definition`; do not require
applications to build a runtime loader or manually coordinate phases.

A single public request type could place main input, underlays, and common
options together. It would reduce duplicated option fields and make promotion
from ordinary to layered loading more uniform. A convenience entry could preserve
the simplest call. Such a design would still need to resolve the existing
overlay-context differences and demonstrate a clearer consumer model. The
maintained examples do not show enough consumer benefit to justify that redesign
in this effort. Retaining the current APIs accepts some duplicated public option
fields and setup changes when adopting underlays; internal consolidation and
clearer guidance address the observed maintenance needs. The decision is based on
the resulting API, rather than the amount of refactoring needed to achieve it.

### Preserve Useful Convenience And Ownership Boundaries

| Surface reviewed | Recommended public end state |
| --- | --- |
| `Source`, `Filesystem`, `Search`, filename groups and presets | Retain typed, reusable source/search descriptions. Discovery selects a concrete source during loading; applications do not loop over complete loads. |
| `FilesystemContext` | Retain the public description and current host/native rules. Consolidate its resolved private representation; do not expose acquisition handles or engine context records. |
| `SequenceIdentityAt` and `SequenceIdentityMatching` | Retain the exact-path convenience and dynamic selector form over the common registration model. Both serve distinct consumer shapes. |
| `Definition`, resolution and validation callbacks | Retain application-owned domain rules inside one recorded lifecycle. Preserve the distinction between mutable recorded resolution and read-only validation. |
| Results, metadata, explanations, source context and diff | Retain detached, safe inspection with consumer-owned presentation. Remove unused inverse conversions without removing supported queries. |
| Root wrappers and private conversions | Retain root-owned public types and explicit ownership conversion under ADR 0006. Consolidate repeated real conversions and delete unused ones. |

The consumer-facing work is to make the ordinary path easier to find and show
how additional features compose, using the existing maintained examples. Update
the adoption guide with a concise choice between simple loading, discovery, and
layered loading, and show which options belong to an input versus a whole load.
Keep exact behavior in its canonical owners. Examples should make application
rules recognizable and avoid requiring consumers to recreate generic merging,
presence, or provenance machinery.

Use the current simple README call, bundled-file and layered catalog examples,
the import-focused prompt catalog, and the discovered sequence catalog to assess
the end state. The latter exercises imports, underlays, independent overlay
context, CLI assignment, and recorded resolution in one workflow. A high number
of options in that example does not by itself justify a new abstraction.

## Internal Target

Keep the root facade, cohesive `internal/engine`, ordered document model, and
private YAML adapter. Use ordinary private records, functions, and focused files
to express responsibilities. Existing mapping combination, sequence combination,
dependency scheduling, schema descriptors, and traversal accounting remain shared.

`executeLoadRequest` stays the visible lifecycle coordinator. It should show
acquisition, assembly, inheritance, decoding/CLI assignment, resolution, secret
processing, validation, and publication in their established order. Extract a
phase only when it gives that work a clear input, output, or ownership boundary.
Do not replace the visible lifecycle with a registry of configurable stages.

### 1. Normalize Loading Inputs And Consolidate Import Acquisition

The current executor constructs an engine `Options[T]` from `loadRequest`, and
underlay acquisition constructs `Options[struct{}]` to call the same input
assembler. `assembleBaseInputTrackedForRole` then combines discovery, directive
processing, version rules, imports, placement, accounting, and contexts. Import
entry points carry long positional lists through several forwarding variants.
This repeats the representation of information already normalized for a load.

In [imports.go](../../internal/engine/imports.go), the
`loadImportedDocumentsTrackedWithVersion`,
`loadImportedDocumentsTrackedWithProcessing`, and
`loadImportedDocumentsTrackedWithProcessingDeferred` variants have corresponding
`loadImportedWithAccess...` variants. Both final signatures carry 13 parameters.
Placement, processing results, sequence policy, accounting, repetition tracking,
namespace identity, and deferred assembly must stay aligned through the chain.
The same file's `importTraversal.visitPath` combines source-admission decisions
in 174 lines, alongside acquisition, pending-item assembly, and evidence work.

Introduce cohesive private acquisition inputs and explicit state ownership,
reusing `loadRequest`, `loadInput`, `acquisitionScope`, and `importTraversal`
where they fit. Translate ordinary and layered public declarations into the
shared loading model once. Acquisition should receive the source, input role,
placement, context, and policies it needs without a fabricated application type
or a reconstructed broad options object. Small adapters may preserve meaningful
entry operations while callers migrate; remove obsolete forwarding variants
within the completed refactor.

Separate immutable policy, mutable processing state, and results. Move import
defaults out of `sourceVersionState` and into the load/acquisition policy owner.
Version state continues to own version processing, projected effective version
location, evidence, and diagnostics. Local and effective version rules have
different meanings and must remain distinguishable.

The state boundaries are especially important:

| Lifetime or scope | State and responsibility |
| --- | --- |
| Whole load | Aggregate resource accounting, application definition/registrations, import defaults, shared version evidence and diagnostics. |
| One strict tier | Repetition tracking shared by that tier's inputs, namespace scheduling anchors, and its inclusion/composition graph relationship. A later tier may reuse a file. |
| Active import traversal | Active routes and inclusion edges, filesystem access ownership, and cycle detection, including edges crossing item-scope boundaries. |
| One composition scope | Peer contributions, pending collection declarations, item-local helpers, and deferred item placement. Nested scopes do not become separate precedence tiers. |
| Retained result | Source records, effective destinations, origins, history, and passive resource-context descriptions. |

Keep repetition tracking tier-scoped. In the current code,
`acquireUnderlayGroupScopes` creates a fresh visited map per group. Preserve valid
reuse across tiers while keeping shared aggregate limits. Namespace equality,
candidate spelling, and stable scheduling keys also serve different purposes.

Give acquisition, already-acquired scope assembly, and evidence projection
focused homes. Keep discovery at the acquisition boundary: resolve a search once
per input consumption, then process the concrete file or absence. Preserve
source IDs and source-local version processing in acquisition order, even when
composition uses a different dependency-ready order. The layered main is acquired
before underlays; lower-tier identity can still inform its later strict assembly.

Within `parseImportDeclarationSpec`, extract boolean/collection/placement field
handling and selector-value parsing where it clarifies responsibilities. Keep
field presence, authored error locations, selector applicability, and the order
of consequential validation visible. Within `selectDirectoryImportCandidates` and
`importTraversal.visitPath`, separate admission and descent decisions from
traversal orchestration where they represent distinct work. Retain the existing
root deduplication, candidate union, exclusions, sorting, and active-path cycle
rules. No shared abstraction should conflate literal first-match main discovery
with multi-file import selection.

### 2. Share Resolved Filesystem Facts Without Sharing Live Handles

`importFilesystem`, `nativeFilesystemAccess`, and `contextsForAcquiredSources`
derive overlapping root/base/namespace facts. The latter reconstructs context
from combinations of source kind and optional fields, including absent input.
Discovery and independent layered overlays make these combinations consequential.
Context construction is used by ordinary acquisition and both selected-overlay
paths, so those callers need to use the same applicable derivation rules.

Use a small engine-owned resolved-context description for the facts actually
needed by acquisition and passive views: namespace identity/kind, resolved root,
source base, and selected source path when present. Preserve the distinction
between host paths and native slash paths. Reuse already resolved facts where
available instead of repeatedly deriving them from the original options.

Resolution and validation can occur at different existing lifecycle points.
The record must not force every source to perform all filesystem checks early.
Context descriptions, library-owned acquisition handles, and returned passive
resource views have different lifetimes. Closing acquisition must remain
explicit on success and failure; retaining context must not retain an open root
handle or assume ownership of a borrowed `fs.FS`.

Cover selected and absent discovery outcomes, root-only absent host context,
native sources, in-memory inputs with explicit context, and independently rooted
overlays. Passive context remains associated with the source that contributed
the value, including retained underlay and inherited values. Use the acquired
source's canonical identity where available. Preserve containment failures,
source associations, deferred search bases, and terminal selected-file errors.

Acquisition and context handling use the same private handoff rather than
maintaining parallel models for overlapping callers. The description does not
replace the public `FilesystemContext` or `ResourceContext` contracts.

### 3. Make Inheritance Combination Results Explicit

Keep the mapping and identified-record adapters and one shared executor.
`applyInheritanceScopeTemplates` currently prepares templates, mutates values
through merge callbacks, projects policy and origins, records replacements and
replay evidence, and enforces budgets in one body. The callbacks mutate several
surrounding result collections, making a combination difficult to review alone.

Give the executor named operations for child/control preparation, parent payload
and policy preparation, combination, evidence construction, and retained-node
accounting. Use a small private result for outputs of one combination where it
replaces unrelated surrounding mutations. Value, policy, origin, replacement,
and sequence-position evidence should come from the same combination outcome;
do not rerun a merge to reconstruct its history.

Keep borrowed authored templates separate from owned resolved payloads and from
retained history snapshots. Parent identity exclusion and child identity/origin
preservation must apply consistently to values and history. Preserve nested
unresolved instructions for destination-local evaluation, policy retirement on
actual replacement, cancellation, and source-version movement through sequences.

The shared Kahn scheduler with stable keys remains unchanged. Resolve enclosing
relationships before nested relationships and retain assembled record order.
Preserve expansion limits and retained-history accounting for shared nodes;
extraction must not charge shared evidence twice or make an unbounded snapshot.

### 4. Separate Projection Handlers And Clarify Schema Assembly

Keep `projectConfiguration` as the schema-checked entry and `valueOperation` as
the operation-state owner. Move substantial struct, map, and sequence projection
into focused handlers. Keep pointer/dynamic dispatch and scalar representation
choices visible. All handlers share the same cycle, depth, and node state.

Struct projection needs particular care: physical members drive traversal,
flattened fields drive name lookup and sensitivity, and an inline container is
not retained as an extra output node. Preserve declaration order, deterministic
map order, nil/empty distinctions, collision diagnostics, codec failures, and
secret classification. Scalar projection retains the existing number, duration,
text-codec, and secret-reference representations. Keep cycle entries active
through child traversal and balance their release on every exit.

In `schemaBuilder.describeFields`, separate field discovery and tag parsing from
inline struct assembly, inline map assembly, and ordinary field registration.
Retain one builder/cache and its recursion detection. Make the paired updates to
`members`, flattened `fields`, `fieldByName`, and `inlineMap` easy to follow.
Keep index-path construction and inherited secret flags intact. These descriptor
views are both needed; combining them into one collection would shift complexity
into decoding and projection.
Keep pointer-chain and recursive-inline decisions explicit, preserve supported
field/tag forms and ambiguity paths, and retain cache/building-state behavior.

Clone traversal review and cleanup are deferred to
[future.md](future.md#4-clone-traversal-review). This effort preserves cloning's
existing behavior while changing the shared schema and projection machinery.
Keep projection's document-building semantics distinct from typed copying.
The mostly explicit dispatch in `decodeValue` and `valueBuilder.build` does not
warrant a generic reflection visitor solely because it has a high complexity
score.

### 5. Remove Unused Inspection Conversions And Consolidate Real Adapters

Remove `toEngineSourceInfo`, `toEngineOrigin`, `toEngineSourceVersionCheck`, and
`toEngineImportSelections` from [conversion.go](../../conversion.go), along with
the engine adapters used only by that chain.
At the reviewed revision, the three callers of `toEngineSourceInfo` are tests;
`toEngineOrigin` has none. `SourceInfoWithPlacement`,
`SourceInfoWithImportSelections`, `importSelectorFromString`, and
`importSelectionOutcomeFromString` in [records.go](../../internal/engine/records.go)
have no production role beyond that reverse chain. Consumers receive inspection
records; production facade operations do not send those records back to the
engine. The unused inverse path adds another ownership mapping to maintain as
inspection evidence grows. Recheck callers at the implementation baseline before
removal.

Rewrite the affected [record tests](../../records_test.go) around real
engine-to-public conversion and detached public inspection. Preserve useful
placement, version evidence, import-selection, and copy-isolation assertions.
Avoid manufacturing replacement production setters solely to keep an old
round-trip fixture working. Existing facade loads already provide genuine sources
and inspection records.

Retain reverse conversions that serve real inputs: `toEngineDiagnostics`, for
example, supports `WriteDiagnostics`. Consolidate repeated override/input
conversion in `toEngineOptions` and `toEngineLayeredOptions` where semantics
match. Keep explicit root-to-engine ownership conversion and the public-boundary
checks. A reflective transport framework or public engine aliases would obscure
the boundary rather than simplify it.

## Scope, Compatibility, And Policy Consequences

The proposed work spans private engine code, private root-facade conversions,
affected tests, consumer guidance, and implementation documentation. Under the
settled answer to [OQ-1](#oq-1-should-the-public-loading-apis-change-in-this-effort),
preserve public types/signatures and the behavior owned by the current contracts,
including:

- Acquisition versus composition ordering, strict scopes versus precedence
  tiers, identity ownership, placement, and source-version protection.
- Discovery exhaustion and error behavior, source lifetime, passive resource
  contexts, and host/native namespace distinctions.
- Defaults, post-decode CLI assignment, recorded resolution, secret handling,
  final registered-identity enforcement, and semantic validation.
- Explicit presence, provenance/history, sensitivity, safe diagnostics and diff,
  frozen inspection, and detached publication/query results.
- Contracted diagnostic codes, paths, coordinates, ordering, and resource limits.

Do not turn incidental helper order, exact private representations, numerical
complexity scores, or allocation counts into new guarantees. Keep the existing
algorithmic remediations effective; watch for repeated whole-tree traversals,
policy scans, or copies introduced by helper extraction.

The recommendation fits the existing architecture policy and ADRs 0006,
0015, 0017, 0018, and 0019. It needs no new architectural ownership decision or
policy revision merely to introduce private helpers. Update the component
overview and import internals when code moves. Accepted ADR decision content
remains unchanged. A public loading-model redesign is outside this effort's
settled scope.

Pre-1.0 public changes are possible under the [release policy](../policy/release.md),
but they must have a consumer benefit and documented impact. This draft does not
propose a parallel compatibility API or temporary migration scaffold. It also
does not make refactoring completion a new release gate or establish that 1.0
is otherwise ready. Future performance experiments remain in
[future.md](future.md#3-performance-experiments); no benchmark campaign was run
or is required to claim readability improvements.

## Validation And Completion

Use the [development guide](../development.md) and
[testing policy](../policy/testing.md) for focused checks and the ordinary full
development check. Preserve existing behavior tests; rewrite tests coupled only
to removed plumbing. Add a test when a consequential handoff risk lacks coverage,
not for every new helper.

| Work area | Existing protection and review focus |
| --- | --- |
| Acquisition and imports | Selection, defaults, scheduling, relative/item placement, source-version evidence, aggregate limits, repetition within versus across tiers, and ordinary/layered equivalence. |
| Resolved contexts | Host/native access, discovery selected/absent outcomes, terminal context failures, source-relative resources, independent overlay context, and handle closure. |
| Inheritance | Mapping and record inheritance, nested destination-local evaluation, child identity, policy lifetime, version movement, history ordering, sensitivity, and retained-node budgets. |
| Projection/schema | Inline fields, recursive schemas, dynamic values, nil/empty values, cycles and limits, text codecs, secret states, callback ownership, and independent loads; preserve existing cloning behavior where shared descriptors/state are affected. |
| Facade and consumers | Forward conversion, detached records, supported API boundaries, source-form equivalence, maintained simple/catalog/discovery examples, and safe explanation/diff. |

Examples of established boundaries include
[source-form equivalence](../../facade_equivalence_test.go),
[discovery integration](../../facade_discovery_test.go),
[final identity validation](../../facade_final_sequence_identity_test.go),
[inheritance history](../../internal/engine/inheritance_history_test.go), and
[projection and cloning](../../internal/engine/projection_test.go).
Use applicable race checks when changing ownership or shared state. Reuse checks
for unchanged content and keep benchmark work separate unless new evidence
justifies it and it is authorized.

Completion requires reviewable evidence that:

- Simple and advanced consumer examples remain concise and valid, with no new
  public concepts required for existing workflows.
- Both load entry points reach one normalized internal model; acquisition no
  longer reconstructs broad options or uses version state to transport defaults.
- Import, context, inheritance, and reflection responsibilities have identifiable
  owners and explicit handoffs without duplicate semantic implementations.
- Unused reverse conversions and their exclusive adapters are removed, with
  useful inspection ownership coverage retained.
- Contracted values, presence, provenance/history, diagnostics, sensitivity,
  resource lifetime, and algorithmic corrections remain protected by appropriate
  tests and source review.
- The reviewed scope is accounted for against all six audit findings, with clone
  traversal review deferred to future work. Completed portions have validation
  evidence rather than being closed because code moved.
- Consumer guidance, contributor references, and internal documentation describe
  the resulting implementation. Current contracts continue to own behavior.

The [implementation plan](implementation.md) defines private records, file owners,
and stage boundaries. No open scope questions remain, and no additional feature
semantics are needed to carry out the selected refactors.

## Settled Decisions

### OQ-1: Should The Public Loading APIs Change In This Effort?

**Settled:** retain `Load`/`Options`, `LoadLayered`/`LayeredOptions`, `Input`, and
`Underlay`, including their existing overlay-context behavior. Consolidate their
private inputs, conversions, and acquisition machinery, and improve consumer
guidance. The [consumer-facing target](#consumer-facing-target) records the
rationale and tradeoffs. This decision governs the consolidation effort; it does
not establish a perpetual restriction on future API design.

### OQ-2: How Much Clone Cleanup Should This Effort Commit To?

**Settled:** defer clone traversal review and any resulting cleanup to
[future.md](future.md#4-clone-traversal-review). Neither the review nor clone
refactoring is part of this consolidation effort. Projection and schema
refactoring remain in scope, including protection of existing cloning behavior
where they share descriptors or operation state. The future review can conclude
that no clone edits are warranted; its goal is demonstrated maintenance benefit.