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genai-toolbox/docs/en/resources/tools/_index.md
Yuan 4827771b78 feat: add support for optional parameters (#617)
Add a `default` field to parameters, that enables users to specify a
default value.

e.g.

```
  parameters:
    - name: name
      type: string
      default: "some-default-value"
      description: The name of the hotel.
```
if this parameter is invoked without specifying `name`, the parameter
would default to "some-default-value"


For parameter manifest, there will be an additional `Required` field.
The default `Required` field is true. If a `default` value is presented,
`Required: false`. Array parameter's item's `Required` field will
inherit the array's `Required` field.

Fixes #475
2025-06-20 10:46:59 -07:00

8.9 KiB

title, type, weight, description
title type weight description
Tools docs 2 Tools define actions an agent can take -- such as reading and writing to a source.

A tool represents an action your agent can take, such as running a SQL statement. You can define Tools as a map in the tools section of your tools.yaml file. Typically, a tool will require a source to act on:

tools:
 search_flights_by_number:
    kind: postgres-sql
    source: my-pg-instance
    statement: |
      SELECT * FROM flights
      WHERE airline = $1
      AND flight_number = $2
      LIMIT 10
    description: |
      Use this tool to get information for a specific flight.
      Takes an airline code and flight number and returns info on the flight.
      Do NOT use this tool with a flight id. Do NOT guess an airline code or flight number.
      An airline code is a code for an airline service consisting of a two-character
      airline designator and followed by a flight number, which is a 1 to 4 digit number.
      For example, if given CY 0123, the airline is "CY", and flight_number is "123".
      Another example for this is DL 1234, the airline is "DL", and flight_number is "1234".
      If the tool returns more than one option choose the date closest to today.
      Example:
      {{
          "airline": "CY",
          "flight_number": "888",
      }}
      Example:
      {{
          "airline": "DL",
          "flight_number": "1234",
      }}
    parameters:
      - name: airline
        type: string
        description: Airline unique 2 letter identifier
      - name: flight_number
        type: string
        description: 1 to 4 digit number

Specifying Parameters

Parameters for each Tool will define what inputs the agent will need to provide to invoke them. Parameters should be pass as a list of Parameter objects:

    parameters:
      - name: airline
        type: string
        description: Airline unique 2 letter identifier
      - name: flight_number
        type: string
        description: 1 to 4 digit number

Basic Parameters

Basic parameters types include string, integer, float, boolean types. In most cases, the description will be provided to the LLM as context on specifying the parameter.

    parameters:
      - name: airline
        type: string
        description: Airline unique 2 letter identifier
field type required description
name string true Name of the parameter.
type string true Must be one of "string", "integer", "float", "boolean" "array"
default parameter type false Default value of the parameter. If provided, the parameter is not required.
description string true Natural language description of the parameter to describe it to the agent.

Array Parameters

The array type is a list of items passed in as a single parameter. To use the array type, you must also specify what kind of items are in the list using the items field:

    parameters:
      - name: preferred_airlines
        type: array
        description: A list of airline, ordered by preference. 
        items:
          name: name 
          type: string
          description: Name of the airline. 
field type required description
name string true Name of the parameter.
type string true Must be "array"
default parameter type false Default value of the parameter. If provided, the parameter is not required.
description string true Natural language description of the parameter to describe it to the agent.
items parameter object true Specify a Parameter object for the type of the values in the array.

{{< notice note >}} Items in array should not have a default value. If provided, it will be ignored. {{< /notice >}}

Authenticated Parameters

Authenticated parameters are automatically populated with user information decoded from ID tokens that are passed in request headers. They do not take input values in request bodies like other parameters. To use authenticated parameters, you must configure the tool to map the required authServices to specific claims within the user's ID token.

  tools:
    search_flights_by_user_id:
        kind: postgres-sql
        source: my-pg-instance
        statement: |
          SELECT * FROM flights WHERE user_id = $1
        parameters:
          - name: user_id
            type: string
            description: Auto-populated from Google login
            authServices:
              # Refer to one of the `authServices` defined
              - name: my-google-auth
              # `sub` is the OIDC claim field for user ID
                field: sub
field type required description
name string true Name of the authServices used to verify the OIDC auth token.
field string true Claim field decoded from the OIDC token used to auto-populate this parameter.

Template Parameters

Template parameters types include string, integer, float, boolean types. In most cases, the description will be provided to the LLM as context on specifying the parameter. Template parameters will be inserted into the SQL statement before executing the prepared statement. They will be inserted without quotes, so to insert a string using template parameters, quotes must be explicitly added within the string.

Template parameter arrays can also be used similarly to basic parameters, and array items must be strings. Once inserted into the SQL statement, the outer layer of quotes will be removed. Therefore to insert strings into the SQL statement, a set of quotes must be explicitly added within the string.

{{< notice warning >}} Because template parameters can directly replace identifiers, column names, and table names, they are prone to SQL injections. Basic parameters are preferred for performance and safety reasons. {{< /notice >}}

tools:
 select_columns_from_table:
    kind: postgres-sql
    source: my-pg-instance
    statement: |
      SELECT {{array .columnNames}} FROM {{.tableName}}
    description: |
      Use this tool to list all information from a specific table.
      Example:
      {{
          "tableName": "flights",
          "columnNames": ["id", "name"]
      }}
    templateParameters:
      - name: tableName
        type: string
        description: Table to select from
      - name: columnNames
        type: array
        description: The columns to select
        items:
          name: column
          type: string
          description: Name of a column to select
field type required description
name string true Name of the template parameter.
type string true Must be one of "string", "integer", "float", "boolean" "array"
description string true Natural language description of the template parameter to describe it to the agent.
items parameter object true (if array) Specify a Parameter object for the type of the values in the array (string only).

Authorized Invocations

You can require an authorization check for any Tool invocation request by specifying an authRequired field. Specify a list of authServices defined in the previous section.

tools:
  search_all_flight:
      kind: postgres-sql
      source: my-pg-instance
      statement: |
        SELECT * FROM flights
      # A list of `authServices` defined previously
      authRequired:
        - my-google-auth
        - other-auth-service

Kinds of tools