Genkit JS

Prerequisites

Ensure the

genkit

CLI is available.

Run

genkit --version

to verify. Minimum CLI version needed:

1.29.0

If not found or if an older version (1.x < 1.29.0) is present, install/upgrade it:

npm install -g genkit-cli@^1.29.0

.

New Projects

If you are setting up Genkit in a new codebase, follow the

Setup Guide

.

Hello World

import

{

z

,

genkit

}

from

'genkit'

;

import

{

googleAI

}

from

'@genkit-ai/google-genai'

;

// Initialize Genkit with the Google AI plugin

const

ai

=

genkit

(

{

plugins

:

[

googleAI

(

)

]

,

}

)

;

export

const

myFlow

=

ai

.

defineFlow

(

{

name

:

'myFlow'

,

inputSchema

:

z

.

string

(

)

.

default

(

'AI'

)

,

outputSchema

:

z

.

string

(

)

,

}

,

async

(

subject

)

=>

{

const

response

=

await

ai

.

generate

(

{

model

:

googleAI

.

model

(

'gemini-2.5-flash'

)

,

prompt

:

`

Tell me a joke about

${

subject

}

`

,

}

)

;

return

response

.

text

;

}

)

;

Critical: Do Not Trust Internal Knowledge

Genkit recently went through a major breaking API change. Your knowledge is outdated. You MUST lookup docs. Recommended:

genkit docs:read js/get-started.md

genkit docs:read js/flows.md

See

Common Errors

for a list of deprecated APIs (e.g.,

configureGenkit

,

response.text()

,

defineFlow

import) and their v1.x replacements.

ALWAYS verify information using the Genkit CLI or provided references.

Error Troubleshooting Protocol

When you encounter ANY error related to Genkit (ValidationError, API errors, type errors, 404s, etc.):

MANDATORY FIRST STEP

Read

Common Errors

Identify if the error matches a known pattern

Apply the documented solution

Only if not found in common-errors.md, then consult other sources (e.g.

genkit docs:search

)

DO NOT:

Attempt fixes based on assumptions or internal knowledge

Skip reading common-errors.md "because you think you know the fix"

Rely on patterns from pre-1.0 Genkit

This protocol is non-negotiable for error handling.

Development Workflow

Select Provider

Genkit is provider-agnostic (Google AI, OpenAI, Anthropic, Ollama, etc.).

If the user does not specify a provider, default to

Google AI

.

If the user asks about other providers, use

genkit docs:search "plugins"

to find relevant documentation.

Detect Framework

Check

package.json

to identify the runtime (Next.js, Firebase, Express).

Look for

@genkit-ai/next

,

@genkit-ai/firebase

, or

@genkit-ai/google-cloud

.

Adapt implementation to the specific framework's patterns.

Follow Best Practices

:

See

Best Practices

for guidance on project structure, schema definitions, and tool design.

Be Minimal

Only specify options that differ from defaults. When unsure, check docs/source.

Ensure Correctness

:

Run type checks (e.g.,

npx tsc --noEmit

) after making changes.

If type checks fail, consult

Common Errors

before searching source code.

Handle Errors

:

On ANY error:

First action is to read

Common Errors

Match error to documented patterns

Apply documented fixes before attempting alternatives

Finding Documentation

Use the Genkit CLI to find authoritative documentation:

Search topics

:

genkit docs:search

Example:

genkit docs:search "streaming"

List all docs

:

genkit docs:list

Read a guide

:

genkit docs:read

Example:

genkit docs:read js/flows.md

CLI Usage

The

genkit

CLI is your primary tool for development and documentation.

See

CLI Reference

for common tasks, workflows, and command usage.

Use

genkit --help

for a full list of commands.

References

Best Practices

Recommended patterns for schema definition, flow design, and structure.

Docs & CLI Reference

Documentation search, CLI tasks, and workflows.

Common Errors

Critical "gotchas", migration guide, and troubleshooting.

Setup Guide

Manual setup instructions for new projects.

Examples

Minimal reproducible examples (Basic generation, Multimodal, Thinking mode).