Summary

• Fix memory_get with corpus=all so a valid empty memory miss can still read a registered wiki supplement.
• Add regression coverage for the non-throwing miss shape returned by the real memory file reader.

Origin / follow-up

• Follows fix(memory): prevent memory-hit starvation in corpus=all by capping per-corpus results (#77337) #77356.
• Gap this fills: the existing corpus=all fallback handled thrown read failures, but not the successful empty miss result returned for missing memory/*.md files.
• Consistency: keeps exact reads aligned with the existing wiki supplement fallback path for read errors and explicit corpus=wiki reads.

Root Cause

• Root cause:
  The root cause is a success-path contract mismatch in executeMemoryReadResult. The memory host source of truth returns a missing but valid in-workspace memory file as { text: "", path }, while executeMemoryReadResult treated every successful read as final by immediately returning jsonResult(result). That caused memory_get corpus=all to stop before the wiki supplement lookup even though the corpus=all contract selected both memory and wiki sources.
• Why this is root-cause fix:
  This fixes the root contract mismatch at the tool boundary that consumes memory read results. It recognizes only the real missing-file result shape: matching path, empty text, and no from/lines/truncation/error metadata. For corpus=all, that exact state now enters the existing supplement read path; existing file reads, partial empty excerpts, disabled results, and corpus=memory behavior still return the original memory result.
• Why it matters / User impact:
  A user asking for corpus=all expects the exact read to search both memory and wiki sources. Before this patch, a missing memory file could hide an available wiki entry even though corpus=all selected both corpora.
• What did NOT change:
  The patch does not change memory indexing, search ranking, provider routing, session visibility, file path validation, corpus=memory, explicit corpus=wiki, or normal successful reads. It only changes the empty-miss branch for memory_get corpus=all.
• Architecture / source-of-truth check:
  The source-of-truth contract is readMemoryFile returning { text: "", path } for missing valid memory files, while buildMemoryReadResult adds from/lines metadata for existing reads. The fix consumes that contract in memory-core rather than changing storage schema, validation, provider routing, or session-state ownership.

Real behavior proof

• Behavior or issue addressed:
  memory_get with corpus=all should return a wiki supplement when the memory backend returns a non-throwing empty miss for the requested valid memory path.
• Real environment tested:
  Local OpenClaw worktree on the patched commit using the production createMemoryGetTool implementation, builtin memory backend, real filesystem workspace, and registered wiki supplement. The proof script confirms memory/entities/alpha.md does not exist on disk before calling the tool.
• Exact steps or command run after this patch:

  node --import tsx "$EVIDENCE_DIR/proof-memory-get-empty-miss.mts"

• Evidence after fix:

  {
    "backend": "builtin",
    "corpus": "all",
    "requestedPath": "memory/entities/alpha.md",
    "targetExistsBeforeRead": false,
    "resultDetails": {
      "corpus": "wiki",
      "path": "memory/entities/alpha.md",
      "title": "Alpha",
      "kind": "entity",
      "fromLine": 7,
      "lineCount": 2,
      "text": "Alpha wiki supplement served after a real empty memory miss."
    }
  }

• Observed result after fix:
  The exact memory_get call returned the wiki supplement details instead of { text: "", path: "memory/entities/alpha.md" } while the requested memory file was absent from the real workspace.
• What was not tested:
  No hosted wiki process or remote agent session was used. The proof covers the local production tool boundary, builtin memory file reader, filesystem miss behavior, and supplement registry path.

Regression Test Plan

• Target test file:
  extensions/memory-core/src/tools.citations.test.ts
• Scenario locked in:
  A memory_get request with corpus=all reads memory/entities/alpha.md, the memory read returns the production missing-file shape { text: "", path }, and a registered wiki supplement for the same path must be returned.
• Why this is the smallest reliable guardrail:
  The regression test locks the exact successful-empty-miss branch that used to bypass the supplement lookup, while existing memory_get|corpus=all tests continue to cover the thrown-error fallback and neighboring corpus behavior.
• Exact steps or command run after this patch:

  node scripts/run-vitest.mjs extensions/memory-core/src/tools.citations.test.ts -t "memory_get|corpus=all"

• Evidence after fix:

  Test Files  1 passed (1)
  Tests  10 passed | 11 skipped (21)
  

• Observed result after fix:
  The new regression test passes with the existing corpus=all and memory_get coverage.
• What was not tested:
  The full tools.citations.test.ts file was not used as the final gate because an unrelated existing citation test timed out before this patch; the focused memory_get|corpus=all subset passed after the fix.

Merge risk

• Risk labels considered:
  No merge-risk label should be needed. merge-risk: session-state was considered because this touches memory-core exact read behavior, but the change does not alter stored session data, session visibility, memory indexing, search ranking, provider routing, message delivery, auth, security boundaries, dependencies, or repository infrastructure.
• Risk explanation:
  The new supplement lookup runs only when requestedCorpus === "all" and the memory read result exactly matches a missing-file empty result. Results that include from/lines, truncation metadata, disabled/error fields, or any non-empty text continue to bypass this fallback.
• Why acceptable:
  The branch adds the behavior that corpus=all already promises without broadening corpus=memory, explicit corpus=wiki, or normal successful memory reads.

Patch quality

• Fix classification:
  Root cause fix.
• Maintainer-ready confidence:
  High. The root cause is isolated to a single success-path early return, the patch is gated to one exact result shape, and both focused regression tests and production-tool proof pass.
• Patch quality notes:
  No unrelated cleanup, docs changes, dependency changes, or generated artifacts are included. The helper's default return false is intentional: non-object values, arrays, and any read result that is not the exact missing-file contract must keep the previous direct-return behavior.