Cida

Cida is an open-source macOS menu-bar assistant for translating and polishing text wherever it is selected. It is aimed at people who want a keyboard-first writing aid without committing to one model vendor: its documented configuration supports OpenAI Chat Completions, OpenAI Responses, Anthropic Messages, and compatible local endpoints. The project is Apache-2.0 licensed; GitHub released v1.5.1 on October 3, 2026.

What it does

Selection translation: Select text and press Option-A to open Cida with translation as the default action. Source and target language settings accept languages, dialects, and styles.
Improve in place: Option-F replaces selected text with a same-language improvement. The original app's Undo command remains the practical way to revert it.
Custom text actions: Create prompt-based actions such as shortening a paragraph, extracting tasks, or reshaping text into an email, then place the most-used action first.
Screen and window translation: Option-S captures an area for local OCR; Option-D translates text under the pointer, and the documented window mode translates newly visible content while retaining normal interaction with the source app.
CLI configuration: The bundled executable can show and update configuration, read an API key from stdin, and make a real connectivity check.

Privacy and trade-offs

The project says API keys live in the macOS Keychain, history is not retained, and text requests go only to the provider selected by the user. Screenshot OCR uses Apple's Vision framework locally; Cida says screenshots are neither saved nor uploaded. Those are project statements, not an independent security audit. Accessibility permission enables selection, in-place translation, and replacement; Screen Recording enables capture and scrolling overlays. Leave either permission off if the workflow does not need it.

A practical workflow

Install the signed and notarized DMG on macOS 15 or newer, choose a provider or local compatible endpoint, then run the app's check command before processing real work. Start with Option-A on a short email or documentation excerpt, verify the output, and create one custom action only after the model and language settings are correct. Use local endpoints when that better fits your data boundary; provider charges still apply where the selected provider bills for inference.

Alternatives and fit

Cida is a desktop text layer, not a document repository or a general coding agent. Compare Obsidian for local notes and Claude Code for repository work. Choose Cida when the job is repeatedly translating or improving text inside existing Mac applications. Read the official README before granting permissions or supplying a provider key.