Recall: Retrieving Memories

The Recall operation searches and retrieves relevant memories from a memory bank. Using the TEMPR retrieval strategy, it finds information that matches your query through multiple search methods—semantic similarity, keyword matching, entity relationships, and temporal reasoning.

Overview

Recall enables intelligent memory retrieval:

• TEMPR multi-strategy search (semantic, keyword, graph, temporal)
• Relevance-ranked results
• Configurable result limits
• Memory type filtering (World Facts, Experience, Observations)

Basic Usage

Python

from hindsight_client import Hindsight

client = Hindsight(
    base_url="https://api.hindsight.vectorize.io",
    api_key="your-api-key"
)

# Simple recall
result = client.recall(
    bank_id="your-bank-id",
    query="What are the user's preferences?"
)

for memory in result.results:
    print(f"[{memory.type}] {memory.text}")

TypeScript

import { HindsightClient } from '@vectorize-io/hindsight-client';

const client = new HindsightClient({
  baseUrl: 'https://api.hindsight.vectorize.io',
  apiKey: 'your-api-key'
});

// Simple recall
const result = await client.recall(
  'your-bank-id',
  "What are the user's preferences?"
);

result.results.forEach(memory => {
  console.log(`[${memory.type}] ${memory.text}`);
});

cURL

curl -X POST https://api.hindsight.vectorize.io/v1/default/banks/{bank_id}/memories/recall \
  -H "Authorization: Bearer your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "query": "What are the user'\''s preferences?"
  }'

How It Works

When you call Recall:

1. Query Processing - Your query is analyzed for semantic meaning, keywords, entities, and temporal references
2. TEMPR Search - Four parallel search methods execute:
   • Semantic - Finds conceptually similar memories
   • Keyword (BM25) - Matches exact terms and phrases
   • Graph - Traverses entity relationships
   • Temporal - Handles time-based queries ("last week", "in March")
3. Ranking - Results from all methods are fused and ordered by relevance
4. Filtering - Optional filters are applied (type, date, etc.)
5. Response - Top matching memories are returned

Request Parameters

Parameter	Type	Required	Description
bank_id	string	Yes	Memory bank to search (in URL path)
query	string	Yes	Search query (natural language)
types	array	No	Filter by memory types
budget	string	No	Search depth: "low", "mid", "high" (default: "mid")
max_tokens	integer	No	Max tokens in response (default: 4096)
trace	boolean	No	Include debug trace (default: false)
query_timestamp	string	No	Reference time for temporal queries (ISO 8601)

Response

{
  "results": [
    {
      "id": "mem_abc123",
      "text": "User prefers dark mode interfaces",
      "type": "observation",
      "entities": ["user"],
      "context": "",
      "mentioned_at": "2024-03-15T10:30:00Z"
    },
    {
      "id": "mem_def456",
      "text": "User's timezone is Pacific Standard Time",
      "type": "world",
      "entities": ["user"],
      "context": "",
      "mentioned_at": "2024-03-14T14:20:00Z"
    }
  ],
  "entities": {
    "user": {
      "entity_id": "ent_456",
      "canonical_name": "user",
      "observations": []
    }
  }
}

Field	Description
results	Array of matching memories
results[].id	Unique memory identifier
results[].text	The memory text
results[].type	Memory category (world, experience, observation)
results[].entities	Entities mentioned in the memory
results[].context	Context when the memory was formed
results[].mentioned_at	When the memory was stored
entities	Entity details for entities in results

Query Best Practices

Use Natural Language

Good

memories = client.recall(
    bank_id=bank_id,
    query="What programming languages does the user know?"
)

Less Effective

memories = client.recall(
    bank_id=bank_id,
    query="programming languages"
)

Be Specific

Good

memories = client.recall(
    bank_id=bank_id,
    query="What did we discuss about the project timeline in our last meeting?"
)

Less Effective

memories = client.recall(
    bank_id=bank_id,
    query="timeline"
)

Ask Questions

Framing queries as questions often yields better results:

# Questions work well
memories = client.recall(query="What are the user's hobbies?")
memories = client.recall(query="When does the client prefer to have meetings?")
memories = client.recall(query="What technology stack is the project using?")

Filtering Results

By Memory Type

# Only get world facts and observations
memories = client.recall(
    bank_id=bank_id,
    query="Tell me about the user",
    types=["world_fact", "observation"]
)

By Relevance Score

# Only highly relevant results
memories = client.recall(
    bank_id=bank_id,
    query="user preferences",
    min_score=0.8
)

Limiting Results

# Get top 5 results
memories = client.recall(
    bank_id=bank_id,
    query="project requirements",
    limit=5
)

Understanding Scores

The relevance score (0-1) indicates how well a memory matches your query:

Score Range	Interpretation
0.9 - 1.0	Excellent match, directly relevant
0.8 - 0.9	Strong match, highly relevant
0.7 - 0.8	Good match, relevant
0.6 - 0.7	Moderate match, somewhat relevant
< 0.6	Weak match, may not be useful

Advanced Patterns

Contextual Search

Combine query with context for better results:

context = "We're discussing the new mobile app feature"
question = "What design preferences have been mentioned?"

memories = client.recall(
    bank_id=bank_id,
    query=f"{context} {question}"
)

Iterative Refinement

Start broad, then narrow down:

# First, broad search
all_prefs = client.recall(query="user preferences")

# Then, specific search based on results
color_prefs = client.recall(query="preferred colors for UI design")

Combining with Retain

Build conversational memory:

# Store what the user says
client.retain(
    bank_id=bank_id,
    content=f"User said: {user_message}"
)

# Recall relevant context for response
context = client.recall(
    bank_id=bank_id,
    query=user_message,
    limit=5
)

Using in the UI

The Recall view in memory banks provides a debugging interface:

1. Navigate to your memory bank
2. Click Recall in the sidebar
3. Enter your search query
4. View results with:
   • Memory content
   • Relevance scores
   • Memory types
   • Retrieval traces

This is useful for:

• Testing query effectiveness
• Debugging retrieval issues
• Understanding score distributions

Token Usage

Recall operations consume tokens based on:

• Query length
• Number of results retrieved
• Memory content sizes

Monitor usage on the Usage Analytics page.

Error Handling

Python

try:
    result = client.recall(bank_id=bank_id, query=query)
    for memory in result.results:
        print(memory.text)
except Exception as e:
    print(f"Error: {e}")

TypeScript

try {
  const result = await client.recall(bankId, query);
  result.results.forEach(m => console.log(m.text));
} catch (error) {
  console.error('Error:', error.message);
}

Common Errors

Error	Cause	Solution
401 Unauthorized	Invalid API key	Check your API key
402 Payment Required	Insufficient credits	Add credits to your account
404 Not Found	Invalid bank_id	Verify the bank exists
400 Bad Request	Empty query	Provide a search query

Performance Tips

1. Limit results - Only request the number of memories you need
2. Filter by type - Narrow scope when you know what you're looking for
3. Use min_score - Filter out low-relevance matches
4. Cache results - Store frequently-needed memories locally