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.
