feat(memory): add batch query recall (recall_many) to UnifiedMemory (#7530)

[Rohitkanithi]

Description

Fixes #7530.

Adds batch query recall (recall_many and arecall_many) to CrewAI's UnifiedMemory system to eliminate sequential embedding round-trips and repeated storage queries when agents or applications search across multiple related terms.

Previously, RecallMemoryTool and callers searching for multiple queries executed a sequential loop:

for query in queries:
    matches = self.memory.recall(query, limit=20)

For $N$ queries, this caused $N$ sequential network round-trips to the embedding API and $N$ sequential storage queries, with deduplication purely based on order of retrieval rather than score.

Solution

1. Memory.recall_many() & Memory.arecall_many() in unified_memory.py:

   • Single-Call Batch Embedding: Uses embed_texts(self._embedder, valid_queries) to embed all queries in a single API round-trip.
   • Concurrent Storage Search: Executes vector storage searches concurrently across query embeddings via ThreadPoolExecutor(max_workers=min(len(embeddings), 8)).
   • Cross-Query Score Fusion & Deduplication: Deduplicates records by record.id, retaining the maximum semantic score across queries (max(semantic_score)), ensuring the final composite score reflects the memory's strongest relevance to the query set.
   • Shallow & Deep Modes: Defaults to depth="shallow" (vector search) for low latency since query strings from tools/agents are already distilled; supports depth="deep" running concurrent RecallFlow per query.
   • Lifecycle & Read Barrier: Maintains consistency with drain_writes(), scope path resolution, access time record touching (touch_records), and event bus lifecycle (MemoryQueryStartedEvent, MemoryQueryCompletedEvent, MemoryQueryFailedEvent).

2. MemoryScope.recall_many() & MemorySlice.recall_many() in memory_scope.py:

   • MemoryScope.recall_many: Resolves scope path and delegates to the bound memory instance.
   • MemorySlice.recall_many: Concurrently searches across all slice scopes, aggregates, deduplicates by record ID, and returns top-ranked results.

3. RecallMemoryTool Optimization in memory_tools.py:

   • Checks hasattr(self.memory, "recall_many") and performs a single self.memory.recall_many(queries, limit=20) call instead of sequential iteration, with backward compatibility fallback.

4. Flow.recall() Extension in runtime/__init__.py:

   • Supports query: str | list[str]. When passed a list[str], delegates to self.memory.recall_many(), matching the interface of Flow.remember(content: str | list[str]).

Testing

• Added 10 unit and integration tests in lib/crewai/tests/memory/test_unified_memory.py:
  • test_memory_recall_many_single_call_batch_embedding: Verifies single API call to embedder for multi-query batch.
  • test_memory_recall_many_cross_query_deduplication_max_score: Verifies cross-query deduplication by ID and retention of highest semantic score.
  • test_memory_recall_many_empty_and_whitespace_queries: Handles empty and whitespace queries cleanly.
  • test_memory_recall_many_with_scope_and_categories: Verifies scope and category filters across batch queries.
  • test_memory_recall_many_read_only_and_touch: Verifies read barrier and access time touch.
  • test_memory_scope_and_slice_recall_many: Tests MemoryScope and MemorySlice batch recall delegation.
  • test_recall_memory_tool_batch_execution: Verifies RecallMemoryTool delegates to recall_many.
  • test_flow_recall_many_delegation: Verifies Flow.recall with list[str] delegates to recall_many.
  • test_memory_recall_many_deep_mode: Verifies depth="deep" mode execution and score aggregation.
  • test_memory_arecall_many: Verifies asynchronous arecall_many.
• All 144 memory tests passing (pytest lib/crewai/tests/memory/).
• Flow runtime tests passing (pytest lib/crewai/tests/test_flow.py).
• Ruff linter (ruff check) and formatter (ruff format --check) passed with 0 errors.

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• lib/crewai/src/crewai/flow/runtime/__init__.py
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📝 Walkthrough

Walkthrough

The pull request adds batched memory recall to UnifiedMemory, scoped memory APIs, Flow.recall, and RecallMemoryTool. It adds concurrent search, deduplication, ranking, filtering, asynchronous delegation, and compatibility fallback behavior.

Changes

Batch memory recall

Layer / File(s)	Summary
UnifiedMemory batch recall lib/crewai/src/crewai/memory/unified_memory.py, lib/crewai/tests/memory/test_unified_memory.py	Memory.recall_many batches embeddings, performs concurrent shallow or deep recall, filters private records, deduplicates matches, ranks results, and applies limits. arecall and arecall_many run synchronous work in worker threads. Tests cover scoring, filtering, touch behavior, deep recall, and asynchronous recall.
Scoped and public recall adapters lib/crewai/src/crewai/memory/memory_scope.py, lib/crewai/src/crewai/flow/runtime/__init__.py, lib/crewai/src/crewai/tools/memory_tools.py, lib/crewai/tests/memory/test_unified_memory.py	MemoryScope and MemorySlice support batched recall and scoped path joining. Flow.recall accepts string lists and falls back to per-query recall for legacy backends. RecallMemoryTool uses recall_many when available. Tests cover delegation, fallback aggregation, and scoped results.

Suggested reviewers: roli-lpci

Sequence Diagram(s)

sequenceDiagram
  participant Flow
  participant Memory
  participant Embedder
  participant VectorStore
  Flow->>Memory: recall_many(queries)
  Memory->>Embedder: embed_texts(queries)
  Memory->>VectorStore: concurrent vector searches
  Memory-->>Flow: ranked deduplicated matches

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Priority: ⬇️ Low

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: adding batch query recall through recall_many to UnifiedMemory.
Description check	✅ Passed	The description covers the linked issue, implementation, compatibility behavior, testing, and quality checks. It uses different section headings from the template and does not include an explicit Addi…
Linked Issues check	✅ Passed	The PR meets the coding requirements in issue #7530. Memory.recall_many() and arecall_many() batch all query embeddings, run vector searches concurrently, oversample candidates, deduplicate by `re…
Out of Scope Changes check	✅ Passed	The changes stay within issue #7530 scope. MemoryScope and MemorySlice delegation, Flow.recall() list support, asynchronous worker execution, access-time behavior, events, and related tests inte…
Docstring Coverage	✅ Passed	Docstring coverage is 90.32% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 31 functions across 5 files.

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Actionable comments posted: 4

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
In `@lib/crewai/src/crewai/flow/runtime/__init__.py`:
- Around line 1019-1022: Update the compatibility fallback around the query loop
in the flow runtime to match recall_many() semantics: aggregate results by
record ID, retain each record’s highest score, sort the consolidated matches by
score, and apply the requested limit before returning. Preserve the existing
memory.recall calls and use the established result and limit fields.

In `@lib/crewai/src/crewai/memory/memory_scope.py`:
- Line 367: Update MemorySlice.recall_many() and MemorySlice.recall() to apply
the provided scope to each selected slice root before delegating to
Memory.recall_many() or Memory.recall(), so roots such as “/projects/alpha” with
scope “/child” resolve to “/projects/alpha/child”; do not merely filter the
original roots or ignore scope.

In `@lib/crewai/src/crewai/memory/unified_memory.py`:
- Line 1314: Update arecall_many to execute recall_many in a worker thread via
await asyncio.to_thread, preserving the existing arguments and return behavior
so embedding, storage, and deep-recall work does not block the event loop.
- Line 899: Update the storage search contract and both built-in backend
implementations so privacy filtering is applied before enforcing the search
limit, using the source/privacy predicate supplied by recall_many. Ensure
recall_many applies the final global limit only after filtering, deduplication,
and sorting, preserving up to limit visible results when include_private is
false.

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