The April 2026 productivity tool wave has a shared format. Fazm reads it from one file.

The pattern is the tool layer, not the app layer. Linear, Notion, Sentry, GitHub, PostHog, Slack, Supabase, Vercel, Cloudflare, Stripe, and others either shipped or polished MCP servers in Q1 and April 2026. Notion Workers for Agents (released in the 3.4 Part 2 update on April 14) is the capstone: productivity tools started treating the MCP endpoint, not the marketing site, as their product surface. This is different from 'productivity apps' updates, which refers to the desktop clients. Productivity tools updates in April 2026 are, disproportionately, updates to server-side protocol endpoints.

~/.fazm/mcp-servers.json. It is loaded inside the Fazm ACP bridge at acp-bridge/src/index.ts lines 1102 to 1137 via readFileSync and JSON.parse. Each entry has four fields: command, args, env, enabled. Changes take effect on the next conversation, no restart required. The Settings UI in Fazm even has a button labeled 'Open' that calls NSWorkspace.shared.selectFile on that exact path at SettingsPage.swift line 1854. You do not need the Settings UI; the JSON file is canonical.

The format is literally `{ "name": { "command": "...", "args": [...], "env": {...}, "enabled": true } }`. The comment at acp-bridge/src/index.ts line 1103 says: "Format mirrors Claude Code's mcpServers". The label in Fazm Settings UI at SettingsPage.swift line 1844 says: "Uses the same format as Claude Code." So any `mcpServers` block you have been using in `.mcp.json` for Claude Code, or in Cursor's config, or in any other Claude-Code-compatible client, copy-pastes into Fazm as-is.

Open ~/.fazm/mcp-servers.json. If the file does not exist, create it with an empty `{}`. Add an entry: `"linear": { "command": "npx", "args": ["-y", "@modelcontextprotocol/server-linear"], "env": { "LINEAR_API_KEY": "..." }, "enabled": true }`. Save. Start a new Fazm conversation. The bridge spawns the process via stdio, lists the tools it exposes (issue creation, cycle management, sub-issue cascade), and makes them available alongside Fazm's built-in macOS accessibility and Playwright tools. That is the full workflow. Zero Fazm binary changes, zero per-tool adapter code.

They are complementary, not redundant. The macOS accessibility surface drives any Mac app that has no public API: click buttons in Logic Pro, type into Fantastical, toggle panels in Pixelmator Pro. The MCP surface talks to any service that ships a proper tool server: query Linear issues, mutate Notion databases, tail Sentry errors, trigger a Stripe refund. Same chat, same turn, different reach. A productivity workflow like 'read the failing Sentry error, find the related Linear issue, type a root-cause note into Fantastical' uses all three in one session.

Yes. The bridge emits a `mcp_servers_available` event on every session start, built at acp-bridge/src/index.ts line 1261: `send({ type: "mcp_servers_available", servers: payload })`. The Swift side parses it in ACPBridge.swift and updates MCPServerManager.shared.activeServers at MCPServerManager.swift lines 117 to 121. That property drives the Settings page 'Built-in' vs 'Custom' list in SettingsPage.swift at lines 1786 to 1830. So every running Fazm shows you, in a built-in UI pane, exactly which MCP productivity tools are loaded right now.

Notion (with Workers for Agents, April 14), Linear (active MCP endpoint, sub-issue cascade exposed), GitHub (first-party MCP server), Sentry (first-party MCP), Slack (community plus Anthropic maintained), Supabase (first-party), Vercel (deploy and env MCPs), Cloudflare (multiple MCPs), Stripe (first-party), PostHog (event and feature flag MCPs). Todoist and Fantastical do not ship MCPs yet; for those, Fazm falls back to the accessibility surface. Any April 2026 productivity tool that publishes an MCP server becomes a one-line add to ~/.fazm/mcp-servers.json with no Fazm release required.

Yes, with one caveat. The Claude Code format has an optional `type` field (http, sse, stdio). Fazm's loader at acp-bridge/src/index.ts line 1108 types the JSON as stdio by default. If your block uses `type: "http"`, configure the HTTP MCP variant on the Fazm side via the McpServerConfigHttp shape at index.ts lines 983 to 988. For the 90 percent case (stdio, spawned binary or npx package), it is a verbatim paste.

Only if you set `enabled: false` yourself. The loader's single gate at acp-bridge/src/index.ts line 1115 is `if (cfg.enabled === false) continue;` and its only other safety check is `if (!cfg.command) continue;` at line 1116. Entries with a valid command and enabled not equal to false always mount. There is no allowlist, no remote block, no telemetry that strips servers.

Two ways. First, check the Fazm log; the loader logs every user MCP server it loads at index.ts line 1132: `logErr("User MCP server loaded: ${name} (${cfg.command})")`. Second, open Fazm Settings to the MCP Servers tab. You will see a 'Built-in' section with playwright, macos-use, whatsapp, google-workspace (if available) and a 'Custom' section with every entry from your JSON that was successfully mounted. The rows are driven by the `activeServers` published property updated at MCPServerManager.swift line 117.