Mail, calendars, and tasks. One local MCP server and CLI.
Provider-neutral, local-first tooling for AI agents, scripts, and you.
Website · Getting started · Providers · Features · Safety · Privacy · Terms · Technical docs
`corr` brings isolated mail, calendar, and task accounts into one terminal—and one local [Model Context Protocol](https://modelcontextprotocol.io/) server. Gmail, Google Calendar, and Google Tasks are available through a Desktop OAuth client in a Google Cloud project you control. Corresync-managed Google OAuth remains dormant. The canonical task tools also include explicit Microsoft To Do, Todoist, TickTick, and CalDAV VTODO routes; remaining task-provider adapters stay unavailable until their contracts are implemented. - Search mail and build one agenda across accounts without collapsing their identity or provider provenance. - Use one stable, provenance-preserving task model as provider adapters become available. - Save private account-local mail searches and relative calendar windows, then run them live without creating a shadow mailbox or calendar cache. - Use the same typed operations from a human-friendly CLI, stable JSON, or an AI agent. - Keep sign-in in a visible browser, an explicit public-client OAuth flow, or an approved local credential store. - Review consequential effects before they happen. Unknown remote outcomes stop for reconciliation instead of being retried automatically. ## What it feels like ```console $ corr mail search --all-accounts \ --query 'subject:"Quarterly plan"' --limit 3 ● work · microsoft-owa Ana Ruiz Plan review · personal · jmap Finance Plan receipt $ corr agenda list --all-accounts \ --start 2026-07-29T00:00:00Z \ --end 2026-07-30T00:00:00Z ``` Connect an agent to the same local core: ```console corr integrations detect corr integrations plan codex claude-code corr integrations setup codex claude-code # Phase A also includes github-copilot, gemini-cli, qwen-code, qoder, kimi-code ``` Then ask naturally: ```text Check my inboxes, calendars, and task lists and summarize what needs attention today. ``` One failed provider becomes an explicit partial failure. Successful results remain available, and writes still require one exact account. ## Choose the route that fits Mail, calendar, and task routes are selected independently. For example, an account can pair IMAP/SMTP mail with a CalDAV calendar; its task route remains a separate explicit choice. | Route | Mail | Calendar | Tasks | Authentication | | --- | --- | --- | --- | --- | | Outlook Web | Typed reads and writes | Selectable calendars; provider-supported Teams link | — | Dedicated visible browser profile | | Google (your OAuth client) | Gmail API reads and writes; no permanent delete | Selectable calendars; Google Meet when advertised | Google Tasks through a separate task-only grant | Your Desktop OAuth client; client credential and grants in the OS keyring | | Microsoft Graph | Typed reads and writes | Selectable calendars; typed Teams-link creation | Microsoft To Do | Your authorized public OAuth client; OS-keyring grant | | Todoist | — | — | Typed Todoist operations | Your authorized public OAuth client; OS-keyring grant | | TickTick | — | — | Typed TickTick operations | Your authorized confidential OAuth client; external secret handle and OS-keyring grant | | JMAP | Typed mail operations | — | — | OS keyring or approved credential helper | | IMAP / SMTP | IMAP read/manage and SMTP draft/send | — | — | OS keyring or approved credential helper | | CalDAV | — | Typed calendar operations and conditional scheduling | VTODO lists, search, sync, and reviewed writes | OS keyring or approved credential helper | Discovery gathers DNS, well-known, and provider metadata without credentials. It never authenticates or adds an account. Microsoft Graph and user-owned Google authorization remain explicit choices and are never automatic fallbacks. Google discovery can offer guided Desktop-client setup, but no Google sign-in starts until a later explicit `corr auth login`. See the [annotated Google setup guide](https://github.com/nkiyohara/corresync/blob/HEAD/docs/google-oauth-setup.md). iCloud has a first-class guided preset over the same provider-neutral IMAP/SMTP and CalDAV adapters. `corr setup` recognizes documented iCloud Mail address families or the complete verified Apple SRV endpoint set, reviews both routes as one account, and uses one external credential handle by default. After the account is added, an explicit handoff can open Apple's app-password page and the OS-owned credential prompt; the `corr` process never reads the app-specific password. Every available v0.9 route above has synthetic provider-contract and application coverage. The user-owned Google API route is available but live-unobserved. Other provider and platform implementations remain **live-unobserved** until an authorized, content-free observation is bound to the exact commit. See [compatibility evidence](https://github.com/nkiyohara/corresync/blob/HEAD/docs/compatibility.md) before connecting a sensitive account. ## From install to a first read Prefer a guided page? Follow [getting started on the website](https://corresync.org/getting-started.html). ### 1. Install The official standalone installers are the shortest path on every platform. They select the latest stable release, verify its archive and candidate binary, install for the current user without elevation, and leave account setup untouched. #### macOS and Linux ```console curl -LsSf https://corresync.org/install.sh | sh corr --version ``` #### Windows PowerShell ```powershell powershell -NoProfile -Command "irm https://corresync.org/install.ps1 | iex" corr --version ``` Review [`install.sh`](https://corresync.org/install.sh) or [`install.ps1`](https://corresync.org/install.ps1) before running it if you prefer. Package managers remain fully supported alternatives: ```console # Homebrew · macOS or Linux brew install nkiyohara/corresync/corresync # WinGet · Windows winget install --id nkiyohara.Corresync --exact # Scoop · Windows scoop bucket add corresync https://github.com/nkiyohara/scoop-corresync scoop install corresync/corresync ``` Direct archives, native Linux packages, version pinning, checksums, and Sigstore provenance are in the [installation guide](https://github.com/nkiyohara/corresync/blob/HEAD/docs/install.md). The [guided website](https://corresync.org/getting-started.html#step-install) keeps the same copy-paste choices visible for people who do not use GitHub regularly. Claude Desktop users can also install the platform-universal `.mcpb` from the [latest release](https://github.com/nkiyohara/corresync/releases/latest). The bundle runs the same verified `corr mcp serve` binary locally over stdio; it does not deploy Corresync or relay mailbox data. Install the CLI first for the explicit account setup and sign-in steps below, then open or drag the `.mcpb` into Claude Desktop. ### Stay current Interactive commands make a quiet, cached release check at startup. If an update exists, Corresync shows the exact command for your installation: `corr update` for the standalone build, or the matching Homebrew, Scoop, or WinGet command. Package-managed files are never changed by Corresync. Stable releases are selected by default. Standalone users who want signed release candidates can choose the preview channel interactively: ```console corr settings ``` The equivalent copy-paste commands for scripts are: ```console corr config set updates.channel preview corr update ``` Switch back with `corr config set updates.channel stable`; Corresync never downgrades the running binary. Preview releases do not enter package-manager catalogs. Standalone users can opt in to verified automatic installation: ```console corr config set updates.auto_install true ``` It never runs during MCP tool calls, configuration changes, daemon work, JSON output, pipes, or other non-interactive paths. The current command continues normally and the new binary is active on the next `corr` start. ### 2. Add and sign in to your account ```console corr setup ``` The guided setup derives a resumable preflight from current local state, optionally installs shell completion at a displayed user-local path, and then performs credential-free account discovery. It previews the selected mail/calendar/task routes and adds an account only after confirmation. Authentication or external-credential access remains a separate choice. The same run can add more accounts, select several detected agent hosts, preview their independent local integration plans, apply only one confirmed plan, and verify each result. Re-running `corr setup` skips healthy work and offers the missing or repairable steps. After choosing a connection route, the wizard presents a service checklist. For a Microsoft account, Outlook Mail and Calendar are preselected and can be changed independently; Microsoft To Do is an optional, explicit Graph authorization. Teams messaging is shown as coming soon while the v0.9 release gate is closed and cannot be selected, persisted, or opened. Discovery is only route evidence: it never proves that any checked service is enabled for the account, and it never triggers a Graph fallback. Run `corr settings` to open the same account wizard; sign in to, rename, select, or remove accounts; and manage updates, safety, and browser sign-in from an arrow-key form. Its Setup guide entry resumes the complete coordinator instead of maintaining another implementation. The top-level Accounts category contains Add account and the configured account list; selecting an account opens only actions for that account. Removal previews the local data it deletes and asks for confirmation; removing the default first asks which remaining account should replace it. Each choice also displays the equivalent command, so the interactive flow teaches the direct CLI. Set `CORRESYNC_ACCESSIBLE=true` for line-oriented screen-reader prompts; type `:cancel` to leave an input step safely. The direct rename form remains: ```console corr account rename personal work ``` Scripts and advanced users retain the deterministic form: ```console corr setup you@example.com --alias personal corr auth login --account personal corr doctor --account personal ``` The direct `setup ADDRESS` form creates the same provider-neutral, secret-free local configuration, performs credential-free discovery, and adds only an automatically selectable first-party route. It never opens a sign-in page. Authentication is a separate, account-specific action. If no route can be selected safely—or if you want an API or standards route— inspect the evidence and choose the exact provider settings: ```console corr account discover reader@example.invalid corr account add reader@example.invalid --help ``` For Gmail, Google Calendar, and Google Tasks, create a Desktop OAuth client in a Google Cloud project you control. Guided setup validates the downloaded client JSON and places its generated credential in the OS keyring; account addition still does not authenticate. Follow the [Google OAuth setup guide](https://github.com/nkiyohara/corresync/blob/HEAD/docs/google-oauth-setup.md) for current Cloud Console screens, audience choices, exact APIs, scopes, import, and login. Before installing, the optional [provider compatibility checker](https://corresync.org/providers.html#check) can classify public evidence for an address. The browser sends only the domain after the `@` in a request body; it never sends the local part, persists the address, or starts sign-in. The public service uses only a fixed DNS resolver and returns no raw DNS record. Skip it whenever you prefer and run `corr account discover ADDRESS` locally. Account addition does not authenticate. OAuth routes require a client registration you are authorized to use. Google additionally requires a separate external handle for its generated Desktop client credential. Standards routes use a keyring entry or explicitly approved helper reference. Passwords and tokens never enter `config.toml`. See [account and provider configuration](https://github.com/nkiyohara/corresync/blob/HEAD/docs/configuration.md). The Outlook Web route opens a dedicated visible profile during the later `auth login`; that window remains the browser-owned session until account logout or daemon shutdown. SSO, MFA, Conditional Access, and organization notices remain inside the provider-owned flow. ### 3. Connect an agent ```console corr mcp setup codex ``` Use `corr mcp --help` for Claude Code, GitHub Copilot CLI, Gemini CLI, Qwen Code, Qoder, Kimi Code CLI, and generic stdio clients. Corresync exposes 45 narrow tools and two read-only monitor resources; there is no HTTP, SSE, remote MCP endpoint, or hosted relay. ## Nothing sends on the first attempt Consequential writes use a server-enforced `preview -> commit` protocol. The first command shows the normalized account, provider, target, recipients, content digest, and version preconditions without performing the effect. ```console printf 'Synthetic body.\n' | \ corr mail send \ --account work \ --to reader@example.invalid \ --subject 'Review example' \ --body-file - ``` After reviewing every field, repeat the exact command with approval: ```console printf 'Synthetic body.\n' | \ corr mail send \ --account work \ --to reader@example.invalid \ --subject 'Review example' \ --body-file - \ --approve ``` Approval is short-lived, single-use, and bound to the caller, account, provider, target, payload, and effect. Changing any reviewed field invalidates it. MCP keeps preview and commit as separate typed tools. [See the complete safety model](https://corresync.org/safety.html). Corresync's public [Privacy Policy](https://corresync.org/privacy.html) explains Google data access, local storage, disclosure, retention, and removal; the [Terms of Use](https://corresync.org/terms.html) preserve the software rights granted by Apache-2.0. ## More than one inbox - **Cross-account views:** bounded mail search and agenda projections retain original account, provider, calendar, time-zone, and partial-failure provenance. - **Read-only import staging:** inspect an explicitly approved local archive, Maildir tree, or supported export without uploading or mutating the source. - **Opt-in monitoring:** move deliberately from `off` to local notification, durable queueing, and finally one approved no-shell runner. Remote egress is a separate consent. - **Privacy-preserving feedback:** generate an allowlisted report locally, review it, then explicitly copy, save, or open a prefilled GitHub page. A separate default-off setting can submit an even smaller allowlist-only public issue through your authenticated `gh` client after an interactive failure. Mailbox, calendar, import, and event-queue values are private, untrusted external data. Their content is never authority to run a command or start an agent. ## Honest edges - Gmail, Google Calendar, and Google Tasks require a user-owned Google Desktop OAuth client. Corresync-managed Google OAuth stays disabled; the user-owned route is synthetic-contract covered and live-unobserved. - Microsoft Graph requires your own authorized public-client registration. Corresync ships no token relay. - Windows desktop notification setup is unavailable because Corresync does not install an AppUserModelID; queue and approved runner modes remain available. - Provider meeting links are requested only when the selected calendar route reports native support. - Cross-compilation and synthetic fixtures do not prove native browser, keyring, IPC, provider, package-manager, Gatekeeper, or SmartScreen behavior. - Teams chat, channels, calls, recordings, and meeting lifecycle management; tenant-wide access; unattended login; TLS interception; arbitrary provider actions; automatic telemetry; and raw crash upload are outside scope. The exact action matrix and typed provider degradations are in [features.md](https://github.com/nkiyohara/corresync/blob/HEAD/docs/features.md). ## One local safety boundary ```text AI agents ───────── MCP over stdio ─┐ ├── typed use cases + effect policy Humans and scripts ──────── corr ───┘ │ │ authenticated local IPC session owner ├── browser-owned sessions ├── explicit OAuth + keyring └── standards adapters ``` The session owner exposes no TCP listener. On Unix, clients authenticate and pin the environment-independent private runtime directory, singleton lock, socket, and peer UID before the local bearer can be sent. On Windows, clients verify the protected named pipe, owner, DACL, server process, and SID first. Read the [architecture](https://github.com/nkiyohara/corresync/blob/HEAD/docs/architecture.md), [authentication model](https://github.com/nkiyohara/corresync/blob/HEAD/docs/authentication.md), and [threat model](https://github.com/nkiyohara/corresync/blob/HEAD/docs/threat-model.md) for the complete boundaries. ## Documentation | I want to… | Start here | | --- | --- | | Install and verify a release | [Installation](https://github.com/nkiyohara/corresync/blob/HEAD/docs/install.md) | | Add accounts and choose routes | [Configuration](https://github.com/nkiyohara/corresync/blob/HEAD/docs/configuration.md) | | Understand browser, OAuth, and standards sign-in | [Authentication](https://github.com/nkiyohara/corresync/blob/HEAD/docs/authentication.md) | | Learn CLI commands | [CLI guide](https://github.com/nkiyohara/corresync/blob/HEAD/docs/cli.md) | | Connect an AI client | [MCP guide](https://github.com/nkiyohara/corresync/blob/HEAD/docs/mcp.md) | | Compare provider actions and degradations | [Feature matrix](https://github.com/nkiyohara/corresync/blob/HEAD/docs/features.md) | | Consume stable machine output | [JSON contract](https://github.com/nkiyohara/corresync/blob/HEAD/docs/json.md) | | Integrate versioned public/local contracts | [Versioning policy](https://github.com/nkiyohara/corresync/blob/HEAD/docs/adr/0020-public-and-local-versioning.md) | | Verify compatibility claims | [Evidence matrix](https://github.com/nkiyohara/corresync/blob/HEAD/docs/compatibility.md) | | Review privacy and Google data handling | [Privacy Policy](https://corresync.org/privacy.html) | | Review use and open-source license terms | [Terms of Use](https://corresync.org/terms.html) | | Connect Google with your own Desktop client | [Google OAuth setup](https://github.com/nkiyohara/corresync/blob/HEAD/docs/google-oauth-setup.md) | | Review the dormant managed-client plan | [Google verification runbook](https://github.com/nkiyohara/corresync/blob/HEAD/docs/google-oauth-verification.md) | | Review every guide | [Documentation map](https://github.com/nkiyohara/corresync/blob/HEAD/docs/README.md) | Users upgrading from versions before v0.7 can follow the [historical migration guide](https://github.com/nkiyohara/corresync/blob/HEAD/docs/migration-v0.7.md). `corr` is the primary command. The product, package, repository, configuration roots, plugin, and MCP server remain named Corresync. ## Contributing and security Read [CONTRIBUTING.md](https://github.com/nkiyohara/corresync/blob/HEAD/CONTRIBUTING.md) and [AGENTS.md](https://github.com/nkiyohara/corresync/blob/HEAD/AGENTS.md). Default tests and CI use only synthetic fixtures: ```console mise exec -- task verify ``` Please report vulnerabilities through [GitHub private vulnerability reporting](https://github.com/nkiyohara/corresync/blob/HEAD/SECURITY.md), never a public issue.