audita/docs/roadmap/implementation.md

# Implementation Plan: Consistent Span Deletion

**Last updated:** 2026-09-25

**Status:** In progress; Stages 1–2 complete.
**Source baseline:** `a83a518` (feature roadmap); application baseline `0b6cd98`.
**Audience:** gpt-5.6-terra coding agent.

## Scope and Execution Rules

Implement [Consistent Span Deletion](span-deletion.md). That document owns the
product intent, target semantics, and acceptance criteria. This document owns the
concrete decisions, ordered work, and validation. Execute Stage 1 through Stage 4
in order. Record actual completion and checks beneath each stage when implemented.
Do not interpret this ready status as implemented behavior.

Read [development guidance](../development.md) and all [agent](../policy/agents.md),
[architecture](../policy/architecture.md), [documentation](../policy/documentation.md),
[testing](../policy/testing.md), and [release](../policy/release.md) policies.
Use graph-first code discovery. Inspect the current workspace before editing;
retain unrelated user work. Commit coherent completed units with plain English
messages, following the agent policy. Do not add permission rounds between stages.

Aim directly at the final state. Do not add temporary compatibility aliases,
feature flags, parallel implementations, or scaffolding for intermediate commits.
Preserve module scope, literal matching, replacement policies, fixed chunks,
required validation, failure isolation,
reporting/debug independence, and existing recovery budgets. Do not implement any
of the [deferred features](future.md), automatic whitespace cleanup, a new deletion
operation type, segment tombstones, or a second normalization pass.

Preserve intended safeguards and outcomes, not incidental implementation choices.
Validator ordering, internal structure, and payload construction may change where
needed to satisfy the feature contract. Current code and tests are evidence to
review, not authority to retain a conflicting restriction. Prefer reusing correct
mechanisms, but do not freeze them merely because they exist.

This replaces the completed resilience implementation plan, which remains in Git
history at `a83a518:docs/roadmap/implementation.md`. Historical resilience decisions
and their remediation are not instructions to rebuild or reverse that work.
During final documentation updates, repair references that describe this filename
as the resilience plan; use current canonical references or the historical revision.
No release, version tag, push, upstream change, or new dependency is part of this
implementation sprint.

## Selected Implementation Decisions

### Schema and library boundary

Remove `minLength: 1` from the `corrected_text` property of
`internal/framework/responseschema/assets/correction_set.v1.json`. Keep the required
field, string type, and all unrelated schema constraints. Empty and whitespace-only
strings are structurally valid; missing, null, and non-string replacements are not.
Keep `original_text` required, string-valued, and at least one character long.
Whitespace-only original spans are valid at the structural boundary and must not
be rejected solely on that basis by domain checks. Replace trimmed-emptiness checks
for original spans with literal empty-string checks in `CorrectionProposal.Validate`
and `ProposalShapeValidator.Validate`, and review other consumers for the same
restriction. Do not trim either span in transit. Resulting-segment checks still use
whitespace-aware emptiness. Preserve module matching policies: `require_unique`
for grammar, spoken-word, and homophones; `replace_all` for glossary.

Keep `CorrectionSetKey`, the schema asset path, ID/name/version, and existing prompt
IDs/`v1` selections. This widens an internal model-response constraint without
changing the correction object shape or creating a second contract to maintain.
The schema hash and PromptKit's rendered/prepared hashes reflect changed content;
no hard-coded hash is a compatibility promise. Ordinary report schema versions,
transcript encoders, configuration, and CLI selections do not change.

PromptKit continues to validate the whole response and own structural repairs.
Do not introduce partial JSON salvage or Audita-side regeneration. Once the schema
accepts empty replacements, normal per-candidate domain filtering handles proposals
that would blank their stage-input segment.

### Validator identity

Rename the existing validator consistently:

| Current | Target |
| --- | --- |
| `non_empty_corrected_text` key and package directory | `non_empty_resulting_segment` |
| `KeyNonEmptyCorrectedText` in registry and metadata | `KeyNonEmptyResultingSegment` |
| `NonEmptyCorrectionValidator` framework type | `NonEmptyResultingSegmentValidator` |

Retain the `empty_resulting_segment` rejection/skip reason, deterministic execution
class, and the resulting-segment safeguard. Reuse preview-based validation where
correct; neither its exact implementation nor chain position is frozen. Do not
retain an old-key alias.
This is an intentional validator identity change in diagnostic/decision records;
document it, including any affected ordinary filtered-proposal metadata. It is not
a new operator-selectable setting. Historical release notes remain untouched.

### Prompt and payload semantics

Review all four proposal definitions and the active validator definitions
(`editorial_review`, `meaning_reversal_review`, `spoken_form_plausibility`) for
consistency. Edit only definitions needing clarification. Review the registered
but inactive `grammar_review` and `spoken_word_review` definitions too; unchanged,
consistent definitions need no edits. Do not activate additional validators as
part of this work.

Where helpful, explain that an empty replacement deletes the identified span,
whitespace-only spans can express spacing corrections, and the resulting segment
must remain nonblank. Do not instruct the model to fabricate padding or content.
A spoken-word example could delete `"uh "` from `"uh hello"`; a grammar example
could reduce two spaces to one. Examples and wording are illustrative, not frozen
requirements or promises of automatic approval. Explain surrounding whitespace
and punctuation only to the extent needed to produce the intended literal result.
Qualify uniqueness by module: glossary uses `replace_all`, while the other three
modules use `require_unique`.

Keep module responsibilities intact. Meaning-reversal review remains a narrow
check for antonyms/reversals, not a new general semantic-equivalence validator.
Spoken-form plausibility retains its phonetic/mistranscription remit. Empty syntax
alone must not determine approval or rejection.

`BuildLLMValidationRequest` already supplies explicit `corrected_text` and full
before/after segment text. Start with that representation and verify that empty
and whitespace-only spans survive it faithfully. Adjust payload construction if
needed for consistency; do not treat its current structure as an independent
requirement. No new deletion flag or synthetic sentinel is needed merely to
represent an empty string.

### Debug representation and outcomes

`CorrectionLedgerEntry` currently uses strings with `omitempty` for both replacement
fields, losing explicit empty values. Change `ProposedCorrectedText` and
`AppliedCorrectedText` to `*string` with their existing JSON names and `omitempty`:

- Every candidate-backed entry has a non-nil proposed value, including `""`.
- Applied entries also have a non-nil applied value, including `""`.
- Rejected, skipped, and interrupted entries omit the applied value.
- Module-level failure entries without a candidate omit both values.

Construct the pointers directly when mapping the corresponding records; use the
same simple convention across all dispositions. Do not build custom marshaling
or a generic optional-value framework. These values remain replacement spans,
not full resulting-segment text. Preserve redaction and the rest of the ledger.

Keep existing operation accounting. A valid approved deletion is an ordinary
applied correction. A candidate that would blank its stage-input segment is
filtered with the existing reason and contributes to the proposal operation's
consolidated filtering recovery. Ordinary editorial/protected-term rejection does
not become a recovery. Multiple proposals can target the same segment; they are
validated against stage input and applied sequentially. A proposal applicable to
that input but made unsafe by an earlier accepted edit is skipped as a conflict,
with no added model error or filtering recovery. Keep the skipped evidence. The
runner's `attributeApplyFiltering` already makes this distinction: verify and reuse
it rather than invent new classification machinery. Structural repairs required
for unrelated defects still count normally.

## Stage 1 — Align Validator Identity and Confirm Domain Semantics

**Work**

- Rename the validator package/type/key described above. Update `New()` wiring,
  `internal/validators/registry.go`, `chains.go`, metadata, framework validators,
  consumers, and tests in one coherent change. Use graph discovery for symbols and
  string searches for serialized keys. Do not globally rewrite historical docs.
- Preserve existing `CorrectionProposal.Validate`, `PreviewProposalForSegment`,
  `ApplyProposals`, and deterministic validation behavior wherever already correct.
  Change original-span trimmed-emptiness checks as specified above, and find any
  equivalent downstream restrictions. Keep empty-original rejection and
  whitespace-aware resulting-segment rejection distinct.
- Extend the existing proposal and validator tests only for missing meaningful
  coverage: empty replacement leaving a nonblank segment, whitespace-only resulting
  text rejection, whitespace-only originals, literal spacing, and apply-time
  reevaluation after an earlier edit. Cover `"hello  world"` with `"  " -> " "`,
  an empty original, and two separate matching whitespace runs under `require_unique`.
  Assert module-policy ambiguity handling without imposing uniqueness on glossary.
  For apply-time reevaluation, use segment `"a b"` and ordered deletions `"a" -> ""`,
  `"b" -> ""`: each is previewable initially, but after the first edit the second
  must be skipped as `empty_resulting_segment`. The surviving text is `" b"`;
  no automatic trim or segment deletion is expected. At the runner/outcome boundary,
  verify this initially applicable second proposal produces skipped debug evidence
  but no model error or filtering recovery. Reuse/extend existing conflict tests;
  a second full CLI scenario is unnecessary for this attribution check.
- Ensure protected-term validation still rejects removal of a protected term with
  an empty replacement. Prefer one case in its existing test table. Retain existing
  metadata-preservation tests rather than duplicating all metadata assertions.
- Update `docs/internal/validators.md` for the renamed implemented validator and
  explain its resulting-segment responsibility; do not yet claim schema alignment.

**Validation**

Run `go test ./internal/framework/proposals ./internal/framework/validators ./internal/validators/... ./internal/framework/runner ./internal/framework/processreport`.
Existing registry/chain tests must use the new identity and verify the required
validation and execution class. Update incidental order assertions if a justified
ordering change preserves those safeguards.
Inspect remaining old-name references, retaining only deliberately historical ones.

**End state:** The accurately named domain validator and application preserve the
agreed behavior. No schema or retry workaround has been introduced.

**Completed 2026-09-25.** Renamed the validator, admitted nonempty whitespace
original spans, and verified literal spacing, blank-result protection, protected
terms, module-policy ambiguity, and apply-time conflict attribution. The specified
focused package tests passed.

## Stage 2 — Align Response Schema, Prompts, and LLM Validation Inputs

**Work**

- Apply the selected schema relaxation and selectively clarify prompts. Preserve
  intended task scope, hardening, and response contracts while correcting conflicting
  instructions wherever encountered within this feature. Review the
  rendered definitions, not just YAML source, using existing PromptKit inspection
  and prompt tests.
- In `internal/framework/responseschema/registry_test.go`, retain the check that
  reported hashes equal hashes of the actual embedded bytes. Remove fixed digest
  expectations that merely freeze asset content; do not replace them with a new
  golden digest for this change.
- Extend the existing real-adapter tests in `internal/framework/llm/adapter_test.go`
  with a bounded table for replacement values: empty string, spaces, ordinary text,
  missing field, null, and a non-string value. Use the embedded schema and local
  HTTP fixture. Give accepted cases a positive repair allowance and assert one
  provider generation, zero repairs, and preservation of the actual string. For
  invalid cases, use zero repair attempts to prove rejection without redundant
  model calls. Include a whitespace-only original in an accepted case and confirm
  an empty original is structurally invalid. Existing tests already own successful
  repair/exhaustion behavior.
- Extend the validation-request tests in
  `internal/framework/validators/llm_validators_test.go` to marshal a real request
  for deleting `"uh "` from `"uh hello"`. Assert that JSON contains the explicit
  empty replacement plus full before/after text, correct identity, and no immediate
  rejection. Include a whitespace-only-original spacing correction in the request
  coverage and verify literal preservation. A field-presence assertion is required;
  decoding into a plain string alone cannot distinguish omitted from empty.
- Update canonical prompt/module guidance for the implemented semantics. Do not
  add exact-prose prompt snapshots or assertions for every new sentence; existing
  parsing/rendering/schema-association tests plus editorial review are sufficient.

**Validation**

Run `go test ./internal/framework/responseschema ./internal/prompts ./internal/framework/llm ./internal/framework/proposal_generation ./internal/framework/validators ./internal/modules/...`.
Confirm missing/non-string replacements still fail structurally and domain-invalid
but schema-valid proposals still reach ordinary filtering without an outer retry.

**End state:** A literal empty replacement can cross the real library/schema
boundary, and the model instructions and validator inputs describe its meaning.

**Completed 2026-09-25.** Relaxed only the replacement length constraint,
clarified the relevant proposal and active validation prompts, and verified
rendering, real-adapter acceptance/rejection, repair counts, and serialized
before/after validator payloads. The specified focused package tests passed.

## Stage 3 — Preserve Empty Replacements in Debug Evidence

**Work**

- Implement the pointer representation selected above in
  `internal/framework/processreport/correction_ledger.go`, updating every mapping
  branch and affected test consumer. Leave other debug structures unchanged where
  their string fields already serialize empty values explicitly.
- Extend `correction_ledger_test.go` with a small serialized-disposition table:
  applied deletion, rejected deletion, skipped deletion, interrupted deletion,
  and a module failure without a candidate. Decode to a map or raw JSON fields to
  check presence, `""` values, and absence of the applied value on unapplied entries.
  Preserve existing decision classification/order tests using the renamed key.
- Update `docs/integrations/output-files.md` to explain the two debug replacement
  fields and the deliberate validator identity change. Keep ordinary schemas and
  report counts unchanged. Update the diagnostics/reporting internal reference
  for the implemented mapping, linking to the public artifact contract.

**Validation**

Run `go test ./internal/framework/processreport ./internal/core/diagnostics ./internal/cli ./cmd/audita`.
Tests must inspect serialized output, not just non-nil in-memory values. Retain
existing configured-secret redaction and debug-off persistence coverage.

**End state:** Debug evidence distinguishes a proposed/applied deletion from an
absent proposal or an edit that was never applied.

## Stage 4 — Verify the Integrated Contract and Finish Documentation

**Work**

Extend `cmd/audita/main_integration_test.go` with representative offline subprocess
cases using its controlled HTTP provider, real configuration/profiles, embedded
schemas, built-in module/validator chains, CLI, and output/report/debug writers.
Keep fixture additions local and small; do not build a new integration framework.
Use explicit fixture sizing so relevant validator candidates fit one batch, and
use stable response indices. Do not rely on production chunk/token defaults or
on concurrent request order to choose responses.

Cover these distinct outcomes:

- **Clean deletion plus another correction:** A spoken-word stage proposes
  `"uh " -> ""` in `"uh hello"` and an independent repetition collapse. Controlled
  validators approve both. Assert corrected transcript, two applied corrections,
  zero model errors/recoveries, zero structural repairs with a positive repair
  allowance, and explicit empty proposed/applied fields in the debug ledger.
- **Whitespace-only span:** A grammar stage reduces one uniquely occurring run
  of two spaces to one. Controlled validators approve it; assert the expected
  text and no error/recovery solely due to whitespace. This proves schema, domain
  validation, and application agree through the actual CLI. Use a compact fixture
  without adding a matrix of whitespace characters or lengths.
- **Partial success with filtering:** Add a proposal to delete all text from a
  separate filler-only segment, preserving that separate segment through fixture
  normalization (use sufficient time separation or explicit normalization settings).
  Assert that this candidate is filtered with `empty_resulting_segment`, the other
  corrections still apply, the blanked segment is instead retained unchanged, and
  the proposal response contributes one consolidated filtering recovery and no
  work-unit error. The renamed deterministic validator must appear in evidence.
- **Ordinary negative decision:** Return a schema-valid deletion proposal, then a
  valid negative decision from meaning-reversal review after earlier checks approve
  it. Assert unchanged affected text, no applied deletion, no error/recovery solely
  from the rejection, and a rejected debug entry. The controlled decision proves
  the chain respects a negative decision, not that an arbitrary real model will
  make the same editorial judgment.

Reuse existing YAML/Markdown/CLI count assertions rather than snapshotting entire
reports. Verify that the clean case's report totals agree with the transcript and
ledger. Compare resulting metadata to the normalized input, since initial
normalization may legitimately merge segments or reassign IDs. Confirm retained
section membership/order in the existing runner boundary tests; add a targeted
assertion only if that property is not already covered for the exercised path.
Do not repeat all cases for all modules, encoders, debug/report combinations, or
platforms: those unchanged mechanisms already have coverage.

Finish the documentation and status work:

- Review current module, validator, prompt, diagnostics, and output references for
  consistency. Add a concise note to `docs/migrations/v2.md` describing the renamed
  validator identity and explicit empty debug replacement fields; no alias or
  migration tool is required. No release note/version is selected in this sprint.
- Review links from other roadmaps to `implementation.md`. References to completed
  resilience stages should point to their historical plan at the recorded revision
  or current canonical behavior, not silently identify this plan as that work.
  Update those references only as needed; do not rewrite historical findings.
- Mark this plan and `span-deletion.md` implemented only after the criteria pass.
  Keep the baseline description historical and retain future.md's exploratory
  whole-segment-removal status. Record concise evidence under completed stages.

**Final validation**

Run `go test ./...` once after the integrated changes. Run `git diff --check` and
validate affected documentation links/examples. Focused stage checks need not be
repeated solely as ceremony. Additional race/platform/live-provider checks are
not automatic gates for this feature; run additional checks only for a concrete
risk introduced by actual changes. This is not a release invocation.

**End state:** The feature roadmap's acceptance criteria are evidenced by real
schema/adapter tests, domain/application tests, serialized debug tests, and
representative complete CLI workflows. The workspace is committed and the docs
describe implemented behavior without claiming whole-segment removal.

## Open Questions

None requiring a product decision remain. Validator names, schema/prompt identity,
debug representation, module scope, test boundaries, and deferred behavior are
selected above. Ordinary implementation details may be resolved idiomatically
within these decisions; a newly discovered conflict with the agreed contract
should be recorded rather than resolved by silently strengthening restrictions.