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Fella is a local-first desktop app for asking plain-language questions about files in a folder. It keeps model-written prose separate from the tool results and checks that support it.

Before you start

After this workflow, you can inspect the sources, computations, and verification findings behind an answer.

The four-part workflow

1

Open a workspace

Choose a folder, drag it into the app, or use /open. Fella catalogs supported files and prepares tables and documents for read-only tools.
2

Ask a question

Ask about tables, documents, trends, comparisons, joins, or correlations. SQL is the default computation path; Python is the escape hatch.
3

Inspect the evidence

Open Evidence to see tool steps, queries or arguments, results, timings, and verification findings. Charts render below the answer.
4

Refine the workspace

Ask a follow-up, add fella.md context, correct vocabulary, switch models, or open another conversation.

Choose a guide

Open a folder

Workspace boundaries, scanning, .fellaignore, and the catalog.

Ask questions

How to phrase questions and how Fella chooses SQL, documents, Python, and charts.

Read the evidence

Follow every computation and understand the verification checklist.

Understand files

Supported formats, table names, documents, and rescanning.

Add context and memory

Teach Fella your vocabulary without turning context into fake evidence.

Choose a model

Hosted providers, custom endpoints, and credential storage.

Manage sessions

Tabs, the history sidebar, focus mode, retrying, and updates.

Commands and shortcuts

The command palette, slash commands, and keyboard reference.

Product boundary

The base agent has no tool that writes, moves, or deletes workspace files. The model chooses read-only tools; the data engine runs their computations and records evidence. Verification checks the completed answer, but it does not prove that a valid query interpreted an ambiguous question correctly.
Python runs inside an embedded WASM capability boundary. Hosted providers receive prompts and tool results for the question. Review privacy and security before using sensitive data.
Fella answers questions about a workspace. It is not a general task agent, file manager, coding assistant, or cloud service.

The harness, engine, and model

The ownership boundaries behind the user workflow.

Privacy and security

Provider egress, credentials, and the Python boundary.