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name: fiftyone-develop-plugin description: Develop custom FiftyOne plugins (operators and panels) from scratch. Use when user wants to create a new plugin, extend FiftyOne with custom operators, build interactive panels, or integrate external APIs into FiftyOne. Guides through requirements, design, coding, testing, and iteration.

Develop FiftyOne Plugins

Overview

Create custom FiftyOne plugins with full lifecycle support: requirements gathering, code generation, local testing, and iterative refinement.

Use this skill when:

• User asks to create/build/develop a FiftyOne plugin
• User wants to add custom functionality to FiftyOne App
• User needs to integrate an external API or service

Prerequisites

• FiftyOne installed (pip install fiftyone)
• Python 3.8+ (for Python plugins)
• Node.js 16+ (only for JavaScript panels)

Key Directives

ALWAYS follow these rules:

1. Understand before coding

Ask clarifying questions. Never assume what the plugin should do.

2. Plan before implementing

Present file structure and design. Get user approval before generating code.

3. Search existing plugins for patterns

Copylist_plugins(enabled=True)
list_operators(builtin_only=False)
get_operator_schema(operator_uri="@voxel51/brain/compute_similarity")

4. Test locally before done

Install plugin and verify it works in FiftyOne App.

5. Iterate on feedback

Refine until the plugin works as expected.

Workflow

Phase 1: Requirements

Ask these questions:

1. "What should your plugin do?" (one sentence)
2. "Operator (action) or Panel (interactive UI)?"
3. "What inputs from the user?"
4. "What outputs/results?"
5. "External APIs or secrets needed?"
6. "Background execution for long tasks?"

Phase 2: Design

1. Search existing plugins for similar patterns
2. Create plan with:
   • Plugin name (@org/plugin-name)
   • File structure
   • Operator/panel specs
   • Input/output definitions
3. Get user approval before coding

See PLUGIN-STRUCTURE.md for file formats.

Phase 3: Generate Code

Create these files:

Reference docs:

• PYTHON-OPERATOR.md
• PYTHON-PANEL.md
• JAVASCRIPT-PANEL.md

Phase 4: Install & Test

Copy# Find plugins directory
python -c "import fiftyone as fo; print(fo.config.plugins_dir)"

# Copy plugin
cp -r ./my-plugin ~/.fiftyone/plugins/

# Verify detection
python -c "import fiftyone as fo; print(fo.plugins.list_plugins())"

Test in App:

Copylaunch_app(dataset_name="test-dataset")
# Press Cmd/Ctrl + ` to open operator browser
# Search for your operator

Phase 5: Iterate

1. Get user feedback
2. Fix issues
3. Re-copy to plugins directory
4. Restart App if needed
5. Repeat until working

Quick Reference

Plugin Types

Operator Config Options

Input Types

Minimal Example

fiftyone.yml:

Copyname: "@myorg/hello-world"
type: plugin
operators:
  - hello_world

init.py:

Copyimport fiftyone.operators as foo
import fiftyone.operators.types as types

class HelloWorld(foo.Operator):
    @property
    def config(self):
        return foo.OperatorConfig(
            name="hello_world",
            label="Hello World"
        )

    def resolve_input(self, ctx):
        inputs = types.Object()
        inputs.str("message", label="Message", default="Hello!")
        return types.Property(inputs)

    def execute(self, ctx):
        print(ctx.params["message"])
        return {"status": "done"}

def register(p):
    p.register(HelloWorld)

Troubleshooting

Plugin not appearing:

• Check fiftyone.yml exists in plugin root
• Verify location: ~/.fiftyone/plugins/
• Check for Python syntax errors
• Restart FiftyOne App

Operator not found:

• Verify operator listed in fiftyone.yml
• Check register() function
• Run list_operators() to debug

Secrets not available:

• Add to fiftyone.yml under secrets:
• Set environment variables before starting FiftyOne

Resources

• Plugin Development Guide
• FiftyOne Plugins Repo
• Operator Types API

License

Copyright 2017-2025, Voxel51, Inc. Apache 2.0 License