feat: codex-quality fallback robustness (partial-failure recovery, fuzz tracking, atomic writes)

[code-yeongyu]

Summary

Atomic TDD commits implementing runtime robustness in split steps:

1. Partial-failure data model (ApplyPatchResult, ApplyPatchFailure, ApplyPatchError)
2. mustReadFiles / mustNotReadFiles recovery instructions for the LLM
3. Fuzz tier tracking (0 / 1 / 100 / 10000) aggregated through result.details.fuzz
4. Partial-failure tool recovery messaging while preserving compat API fail-fast behavior

Backward compatibility

• Wire format unchanged: tool name, description, Lark grammar, parameters schema remain canonical
• applyPatch(cwd, patchText): Promise<string[]> signature unchanged
• applyPatch retains fail-fast semantics: first hunk failure aborts processing, no later hunks attempted
• New applyPatchDetailed(cwd, patchText): Promise<ApplyPatchResult> is additive and used for accumulation/recovery

Commits

• fe29036 test: cover tool recovery message for partial applyPatchDetailed failure
• 0ceb2b7 feat: aggregate fuzz across hunks into result.details.fuzz
• 2db695e feat: extend seekSequence to return {index, fuzz} tuple
• bc2e43c test: cover seekSequence returning fuzz tier 0/1/100/10000
• 3304b89 refactor: keep legacy applyPatch fail-fast semantics
• 21dfaed test: cover applyPatch retains fail-fast on first hunk failure
• f378f0b feat: route tool execute() through applyPatchDetailed for partial-failure recovery message
• e773710 feat: build mustReadFiles/mustNotReadFiles in createRecoveryInstructions
• b13ce15 feat: implement applyPatchDetailed with failure accumulation
• 8c4ba20 feat: introduce ApplyPatchResult, ApplyPatchFailure, ApplyPatchRecoveryInstructions types and ApplyPatchError class
• 18fd0b9 test: cover applyPatchDetailed accumulates per-hunk failures

Tests

• Added 4 test commits for detailed accumulation, fail-fast compatibility, fuzz tiers, and tool recovery text
• npm run check clean
• npm test all green

[cubic-dev-ai]

2 issues found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/index.ts">

<violation number="1" location="src/index.ts:689">
P2: Failure output is always labeled as a partial failure, so full failures receive misleading recovery instructions.</violation>

<violation number="2" location="src/index.ts:761">
P1: `hasPartialSuccess` is computed from summaries, which can miss side effects from a failed move hunk after the destination write succeeds.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Failure output is always labeled as a partial failure, so full failures receive misleading recovery instructions.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At src/index.ts, line 689:

<comment>Failure output is always labeled as a partial failure, so full failures receive misleading recovery instructions.</comment>

<file context>
@@ -559,64 +654,122 @@ function replaceChunks(content: string, filePath: string, chunks: PatchChunk[]):
+	if (failedFiles.length === 0) {
+		return result.summaries.join("\n");
+	}
+	return [
+		"apply_patch partially failed.",
+		`Failed: ${failedFiles.join(", ")}`,
</file context>

Suggested change

	return [
	"apply_patch partially failed.",
	`Failed: ${failedFiles.join(", ")}`,
	`Recovery: MUST read ${failedFiles.join(" and ")} before retrying.`,
	"Earlier file actions in this patch were already applied.",
	"Recovery: MUST NOT reread other files from this patch unless a specific dependency requires it.",
	].join("\n");
	if (!result.hasPartialSuccess) {
	return ["apply_patch failed.", `Failed: ${failedFiles.join(", ")}`].join("\n");
	}
	return [
	"apply_patch partially failed.",
	`Failed: ${failedFiles.join(", ")}`,
	`Recovery: MUST read ${failedFiles.join(" and ")} before retrying.`,
	"Earlier file actions in this patch were already applied.",
	"Recovery: MUST NOT reread other files from this patch unless a specific dependency requires it.",
	].join("\n");