Create and test lambda tools

To create a Lambda Tool with the API:

1. Meet the following prerequisites:
   • Access to the Vectara API with tool creation permissions.
   • Basic Python familiarity.
   • API key.
2. Define a simple function. The entry point must be process.
   This example calculates customer scores based on their activity metrics:

   CUSTOMER_SCORE_CALCULATOR.PY

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   Notes

   • Use type annotations for automatic schema discovery.
   • Parameters with default values become optional in the schema.
   • Return a JSON-serializable dictionary.
3. Create the Lambda Tool with the API.

   CREATE LAMBDA TOOL REQUEST

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   Example response:

   CREATE LAMBDA TOOL RESPONSE

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The input and output schemas were automatically discovered from the function's type annotations.

Test Lambda Tools

Before deploying your Lambda Tool to agents, test it with sample inputs to verify correct behavior.

Test your Lambda Tool

TEST LAMBDA TOOL REQUEST

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Test Response:

TEST LAMBDA TOOL RESPONSE

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Update lambda tools

Modify existing Lambda Tools to update code, configuration, or metadata:

UPDATE LAMBDA TOOL REQUEST

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When you update the code, schemas are automatically re-discovered from the new function signature.

List all lambda tools

LIST LAMBDA TOOLS

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Disable a lambda tool

DISABLE LAMBDA TOOL

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Delete a lambda tool

DELETE LAMBDA TOOL

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Available Python libraries

Lambda Tools run in a secure sandbox on Python 3.12. Your code can import the Python standard library plus preinstalled third-party packages including:

• numpy - Numerical arrays and vectorized math
• pandas - DataFrames for tabular data analysis
• python-calamine, openpyxl, and xlrd - Spreadsheet reading; import python-calamine as python_calamine
• xlsxwriter - XLSX generation
• python-pptx - PPTX creation and editing; import it as pptx
• python-docx - DOCX creation and editing; import it as docx

Commonly used standard-library modules include json for encoding and decoding, math for mathematical functions, datetime for dates and times, collections for container datatypes, itertools and functools for iterator and higher-order functions, re for regular expressions, time for time access, and typing for type hints.

Security Constraints

Lambda Tools cannot:

• Install additional packages (pip install is not available)
• Access the network directly (use composable lambda tools to call tools like web_get instead)
• Persist state between executions — the temporary workspace is writable but discarded after each execution

Deprecated: max_memory_mb

The max_memory_mb field on a lambda tool's execution configuration is deprecated and ignored. Memory is fixed by the execution environment and cannot be configured per function. Setting the field has no effect.

Use a lambda tool with an agent

After creating a Lambda Tool, you can configure agents to use it through inline tool configurations. You reference the tool by its ID and optionally provide argument overrides.

Inline configuration

Use an inline configuration to point an agent to an existing Lambda Tool by ID:

INLINE LAMBDA TOOL CONFIGURATION (INSIDE AGENT)

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The argument_override field allows you to:

• Hardcode specific values that the LLM cannot change (e.g., "customer_tier": "enterprise")
• Use dynamic context references with $ref to pull values from session or agent metadata (e.g., {"$ref": "session.metadata.search_query"})

Reusable Lambda tool configuration

You can also create a reusable LambdaToolConfiguration that can be referenced across multiple agents. This approach is useful for consistent, governed usage of Lambda Tools.

CREATE REUSABLE LAMBDA TOOL CONFIGURATION

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Then reference this configuration in your agent:

REFERENCE LAMBDA TOOL CONFIGURATION IN AGENT

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