FastDoc AI is a VS Code extension that generates inline documentation for JavaScript, TypeScript, JSX, TSX, and Python functions using a local or remote LLM backend.

Features

Generate JSDoc or Python docstrings from the command palette, editor context menu, keyboard shortcut, or FastDoc sidebar.
Use local Ollama by default so source code stays on your machine.
Optionally connect to OpenAI-compatible APIs or Anthropic Claude.
Store remote API keys securely in VS Code SecretStorage.
Detect existing documentation and ask before overwriting it.
Preview and edit generated documentation before insertion.
Generate 1-3 variants and compare them in the sidebar.
Remember the last provider/model per workspace.

Quick Start

Install FastDoc AI from the VS Code Marketplace.
Open a JavaScript, TypeScript, JSX, TSX, or Python file.
Place your cursor on a function, or within 3 lines of one.
Run FastDoc: Generate Documentation from the Command Palette.
Review the generated documentation and insert it.

Keyboard shortcut:

macOS: Cmd+Shift+D
Windows/Linux: Ctrl+Shift+D

Backend Setup

FastDoc needs an LLM backend.

Local Ollama

Ollama is the default backend.

ollama pull gpt-oss:20b
ollama serve

FastDoc connects to http://localhost:11434 by default.

Remote Providers

Use FastDoc: Open Settings to configure:

OpenAI-compatible API URL, for example https://api.openai.com/v1
Anthropic API, with the URL left blank for https://api.anthropic.com
Model name
API key
Variant count
Request timeout

API keys are stored in VS Code SecretStorage. Use FastDoc: Clear API Key to remove the stored key.

Commands

Command	Description
FastDoc: Generate Documentation	Generate documentation for the nearest function.
FastDoc: Set API Key	Store a remote provider API key securely.
FastDoc: Clear API Key	Remove the stored API key.
FastDoc: Open Settings	Open the FastDoc settings panel.

Settings

Setting	Default	Description
`fastdoc.llm.provider`	`ollama`	`ollama`, `openai`, or `anthropic`. The legacy value `remote` maps to `openai`.
`fastdoc.llm.model`	`gpt-oss:20b`	Model name used for generation.
`fastdoc.llm.ollamaUrl`	`http://localhost:11434`	Ollama API base URL.
`fastdoc.llm.remoteUrl`	empty	Remote provider base URL.
`fastdoc.llm.apiKey`	empty	Deprecated fallback. Use SecretStorage through the commands/settings panel.
`fastdoc.llm.variantCount`	`1`	Number of variants to generate, from 1 to 3.
`fastdoc.llm.timeoutMs`	`30000`	Request timeout in milliseconds.

Troubleshooting

Symptom	Fix
No function found	Move the cursor onto the function name or within 3 lines of the signature.
Ollama connection fails	Confirm Ollama is running and `fastdoc.llm.ollamaUrl` is correct.
Remote 401/403 error	Update the stored API key.
Remote model error	Check that the selected model is valid for the provider.
Generic documentation	Try a stronger model or provide more source context around the function.

Privacy

The default Ollama backend runs locally. Remote providers send the selected source context to the configured provider, and FastDoc shows a privacy warning before remote generation.