fleet-memory/hindsight-api-slim
Nicolò Boschi 57f154454d
fix(recall): cap entity fanout in graph expansion (#911)
* fix(recall): cap entity fanout in graph expansion to prevent slow queries

On large banks, the entity co-occurrence self-join in _expand_combined()
produces massive intermediate row counts when seeds reference high-fanout
entities (e.g. an entity with 25K+ mentions). This causes recall latency
to degrade significantly.

Changes:
- Replace unbounded entity self-join with LATERAL per-entity cap
  (graph_per_entity_limit, default 200), reducing intermediate rows
  from potentially millions to at most num_entities * 200
- Add ORDER BY unit_id DESC in LATERAL subquery for deterministic
  recency-biased sampling (rides the PK index, no extra sort)
- Add timeout fallback (graph_expansion_timeout, default 10s) that
  drops entity expansion and falls back to semantic+causal only
- Add composite index (entity_id, unit_id) on unit_entities for
  index-only scans in the LATERAL subquery
- Merge 3 unmerged migration heads into one
- Fix recall_perf.py dotenv override issue

Unlike the approach in #895, this does NOT filter out hub entities
entirely — all entities are kept but capped equally, preserving
retrieval quality for queries about frequently-mentioned entities.

Benchmarked on a 67K-unit bank (top entity = 25K mentions):
- retrieval_graph: 0.337s → 0.055s (84% faster)
- end-to-end recall: 0.912s → 0.519s (43% faster)

* fix(tests): fix broken test_combined_scoring and test_reranking_proof_count

- test_combined_scoring: replace MagicMock(spec=RetrievalResult) with real
  dataclass instances — MagicMock attributes returned nested mocks that
  failed on >= comparisons with int
- test_reranking_proof_count: remove deleted `embedding` param from
  RetrievalResult constructor, use None for occurred_start/end to get
  neutral recency (datetime.now gave recency=1.0 which boosted scores)

* refactor: rename config to link_expansion_ prefix, fix observation fanout

- Rename GRAPH_PER_ENTITY_LIMIT → LINK_EXPANSION_PER_ENTITY_LIMIT and
  GRAPH_EXPANSION_TIMEOUT → LINK_EXPANSION_TIMEOUT to follow the
  convention that these are specific to the link_expansion graph retriever
- Apply the same LATERAL per-entity cap to _expand_observations(), which
  had the same unbounded self-join through unit_entities

* style: fix formatting in config.py
2026-04-07 18:59:50 +02:00
..
hindsight_api fix(recall): cap entity fanout in graph expansion (#911) 2026-04-07 18:59:50 +02:00
tests fix(recall): cap entity fanout in graph expansion (#911) 2026-04-07 18:59:50 +02:00
pyproject.toml security: bump litellm to >=1.83.0 (#912) 2026-04-07 16:54:24 +02:00
README.md feat: introduce hindsight-api-slim and hindsight-all-slim packages (#560) 2026-03-13 13:50:03 +01:00

Hindsight API

Memory System for AI Agents — Temporal + Semantic + Entity Memory Architecture using PostgreSQL with pgvector.

Hindsight gives AI agents persistent memory that works like human memory: it stores facts, tracks entities and relationships, handles temporal reasoning ("what happened last spring?"), and forms opinions based on configurable disposition traits.

Installation

pip install hindsight-api

Quick Start

Run the Server

# Set your LLM provider
export HINDSIGHT_API_LLM_PROVIDER=openai
export HINDSIGHT_API_LLM_API_KEY=sk-xxxxxxxxxxxx

# Start the server (uses embedded PostgreSQL by default)
hindsight-api

The server starts at http://localhost:8888 with:

  • REST API for memory operations
  • MCP server at /mcp for tool-use integration

Use the Python API

from hindsight_api import MemoryEngine

# Create and initialize the memory engine
memory = MemoryEngine()
await memory.initialize()

# Create a memory bank for your agent
bank = await memory.create_memory_bank(
    name="my-assistant",
    background="A helpful coding assistant"
)

# Store a memory
await memory.retain(
    memory_bank_id=bank.id,
    content="The user prefers Python for data science projects"
)

# Recall memories
results = await memory.recall(
    memory_bank_id=bank.id,
    query="What programming language does the user prefer?"
)

# Reflect with reasoning
response = await memory.reflect(
    memory_bank_id=bank.id,
    query="Should I recommend Python or R for this ML project?"
)

CLI Options

hindsight-api --help

# Common options
hindsight-api --port 9000          # Custom port (default: 8888)
hindsight-api --host 127.0.0.1     # Bind to localhost only
hindsight-api --workers 4          # Multiple worker processes
hindsight-api --log-level debug    # Verbose logging

Configuration

Configure via environment variables:

Variable Description Default
HINDSIGHT_API_DATABASE_URL PostgreSQL connection string pg0 (embedded)
HINDSIGHT_API_LLM_PROVIDER openai, anthropic, gemini, groq, ollama, lmstudio openai
HINDSIGHT_API_LLM_API_KEY API key for LLM provider -
HINDSIGHT_API_LLM_MODEL Model name gpt-4o-mini
HINDSIGHT_API_HOST Server bind address 0.0.0.0
HINDSIGHT_API_PORT Server port 8888

Example with External PostgreSQL

export HINDSIGHT_API_DATABASE_URL=postgresql://user:pass@localhost:5432/hindsight
export HINDSIGHT_API_LLM_PROVIDER=groq
export HINDSIGHT_API_LLM_API_KEY=gsk_xxxxxxxxxxxx

hindsight-api

Docker

docker run --rm -it -p 8888:8888 \
  -e HINDSIGHT_API_LLM_API_KEY=$OPENAI_API_KEY \
  -v $HOME/.hindsight-docker:/home/hindsight/.pg0 \
  ghcr.io/vectorize-io/hindsight:latest

MCP Server

For local MCP integration without running the full API server:

hindsight-local-mcp

This runs a stdio-based MCP server that can be used directly with MCP-compatible clients.

Key Features

  • Multi-Strategy Retrieval (TEMPR) — Semantic, keyword, graph, and temporal search combined with RRF fusion
  • Entity Graph — Automatic entity extraction and relationship tracking
  • Temporal Reasoning — Native support for time-based queries
  • Disposition Traits — Configurable skepticism, literalism, and empathy influence opinion formation
  • Three Memory Types — World facts, bank actions, and formed opinions with confidence scores

Documentation

Full documentation: https://hindsight.vectorize.io

License

Apache 2.0