Capsulate vs Core
A side-by-side look at the Capsulate and Core MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Capsulate for os automation work as a local process; choose Core for os automation as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose Capsulate when
- You need dedicated capabilities in the OS Automation domain.
- You prefer a local stdio subprocess transport.
- You have the keys it needs:
CAPSULATE_API_KEY. - You want tools like
capsulate_launch, capsulate_list, capsulate_get.
Choose Core when
- You need dedicated capabilities in the OS Automation domain.
- You prefer a local stdio subprocess transport.
- You want tools like
electron_assert_pattern, electron_attach, electron_check.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | OS Automation | OS Automation |
| Quality signal | 61/100 · Good | 57/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | Not declared | Not declared |
| Pricing | Not declared | Not declared |
| Required env vars | CAPSULATE_API_KEY | None listed |
| Verified owner | Community listing | Community listing |
| GitHub stars | 0 | 12 |
| Directory activity | 1 views 0 installs 0 upvotes | 1 views 0 installs 0 upvotes |
| Tools | 54 | 55 |
| Full listing | View Capsulate | View Core |
Tools & capabilities
Capsulate tools 54
capsulate_launchLaunch a new isolated cloud sandbox (capsule) and (by default) wait until it is ready. Returns the capsule id and connection info. Use the returned sessionId for exec/files/etc. With skill, the capsule is the skill's environment (its saved template with the software set up) and the skill's setup procedure has run, so you can use its procedures right away.capsulate_listList the team's active capsules.capsulate_getFetch a capsule's full details by id.capsulate_destroyTerminate a capsule and release its resources.capsulate_execExecute a command inside a capsule and return stdout, stderr, and the exit code. Provide the command as an argv array, e.g. ['ls','-la','/workspace']. Commands first: files, installs, settings, scripts and data are one call here, a fraction of a second, where the screen takes many steps. On a Linux desktop capsule it runs as the desktop user 'capsulate' (home folder, DISPLAY :1, so apps open on the shared screen); prefix 'sudo' for root. On Windows pass ['powershell.exe', '-Command', '<script>']: it runs in the desktop session's PowerShell, about 0.3 s. It works while a person holds the screen.capsulate_run_codeRun a snippet of code inside a capsule: python, node or bash on Linux, powershell on Windows (about 0.3 s). Returns stdout/stderr/exit. Faster than doing the same on the screen.capsulate_write_fileWrite a UTF-8 text file inside a capsule (the folder is created). One call, far faster than typing it into an editor on the screen; open it afterwards with capsulate_open if the person should see it.capsulate_read_fileRead a UTF-8 text file from inside a capsule. One call, no screen needed.capsulate_set_envSet environment variables inside a running capsule.capsulate_screenshotCapture a screenshot of a desktop capsule. Returns the image so you can see the screen. For a smaller, faster image ask for format 'jpeg', a scale such as 0.5, or only a region (x, y, w, h) of the screen; the text after the image says how its points map back to screen pixels, which click and the other tools take.capsulate_clickClick at pixel (x, y) in a desktop capsule. Pass screenshot:true to see the screen after the click.capsulate_typeType text into the focused field of a desktop capsule.- +42 more on the listing page
Core tools 55
electron_assert_patternValidate, in a single check (no polling), that an element's text or a named attribute matches a pattern. Target by ref or selector. With `attribute` set, reads that attribute; otherwise reads the element's trimmed text. Provide exactly one of: equals, contains, matches_regex. Optional flags (any of i, m, s, u) apply to matches_regex; g and y are rejected as stateful. Returns: { ok, session_id, matched, actual }. Errors: EXPECTATION_FAILED (element found but its value did not match the pattern — details carry expected + actual; a missing attribute reads as actual: null), SELECTOR_NO_MATCH (no element matched — this is one-shot, so a missing element is a precondition failure, not a retry; carries similar_refs), REF_NOT_FOUND (stale ref), TRANSPORT_UNSUPPORTED, NOT_RUNNING, BAD_ARGUMENT (no/multiple predicates, invalid regex or flags, or ref+selector both/neither).electron_attachAttach to an already-running Electron app exposing a CDP debug endpoint (use electron_discover_running to find one, or start the app with --remote-debugging-port). Provide port (+ optional loopback host) or a loopback cdpUrl; pid alone is not attachable over CDP but, when supplied alongside, lets stop escalate to SIGKILL. The CDP transport supports eval/read/observe and core interaction surfaces against the attached app. The selected CDP page is also the default snapshot/find surface; explicit iframe/webview surface targeting remains unavailable. Returns: { ok, session_id, transport, windows, capabilities }. Errors: TRANSPORT_UNSUPPORTED (no attach-capable transport), CDP_DISCONNECTED (endpoint unreachable or dropped; retryable), CDP_TIMEOUT (handshake/method timeout; retryable), BAD_ARGUMENT (missing target selector or non-loopback endpoint).electron_checkCheck the checkbox/radio identified by ref or selector (no-op if already checked). Options: force, timeoutMs. Returns: { ok, session_id, target, checked: true }. Errors: REF_NOT_FOUND / SELECTOR_NO_MATCH (carries similar_refs), ELEMENT_NOT_VISIBLE (retryable), ELEMENT_DISABLED, NOT_RUNNING, BAD_ARGUMENT.electron_clear_inputClear the value of the input/textarea identified by ref or selector (sets it to empty). Options: force, timeoutMs. Returns: { ok, session_id, target, cleared }. Errors: REF_NOT_FOUND / SELECTOR_NO_MATCH (carries similar_refs), ELEMENT_NOT_VISIBLE (retryable), ELEMENT_DISABLED, NOT_RUNNING, BAD_ARGUMENT.electron_clickClick the element identified by ref (from a snapshot) or selector. Options: button (left|right|middle, default left), clickCount (2 = double-click), force (bypass actionability), timeoutMs. Returns: { ok, session_id, target }. Errors: REF_NOT_FOUND / SELECTOR_NO_MATCH (no such element — re-snapshot; not retryable, carries similar_refs), ELEMENT_NOT_VISIBLE (retryable), ELEMENT_DISABLED (not retryable), NOT_RUNNING, BAD_ARGUMENT (ref+selector both/neither).electron_console_logsRead the captured renderer console output for the session, newest-relevant entries last. Filters (all optional, ANDed): type (one or more of log/info/warning/error/debug/...), match (a regular expression the text must match), since (epoch ms — only entries at/after it), limit (max entries, default 200, max 1000 — the most recent are kept). Returns: { ok, session_id, entries: [{ type, text, timestamp, windowId?, location? }], count, overflowed }. overflowed is the number of older entries the buffer dropped. Errors: NOT_RUNNING, BAD_ARGUMENT (invalid regex, or multiple sessions).electron_detachDisconnect from an attached or injected app without stopping it. A launch-owned session cannot detach because its transport owns the process; this includes Playwright development launches and packaged CDP launches. Use electron_stop for that case. Returns: { ok, session_id, detached: true }. Errors: TRANSPORT_UNSUPPORTED (launch-owned session; not retryable), NOT_RUNNING (no such session), BAD_ARGUMENT (multiple sessions).electron_dialog_handlerArm the auto-responder for native JS dialogs (alert/confirm/prompt/beforeunload) and read which dialogs fired. Dialogs block the renderer, so the policy is applied automatically the instant one appears. Arming args (all optional): action (accept|dismiss — the default for every dialog), perType (per-kind overrides, e.g. {"confirm":"accept","beforeunload":"dismiss"}, falls back to action), promptText (text submitted to prompt() when it is accepted), oneShot (apply to exactly the next dialog, then revert to dismiss). With NO arming args the call is inspect-only and leaves the policy unchanged. Read args (all optional): type (one or more kinds to include), since (epoch ms), limit (max events, default 50, max 200 — most recent kept), clear (flush the whole buffer after reading). Until armed, the default policy is dismiss, so dialogs never hang the app. Returns: { ok, session_id, policy, entries: [{ type, message, action, defaultValue?, promptText?, timestamp, windowId? }], count, overflowed }. overflowed counts dropped events across the whole buffer, not just the returned (type/since/limit-filtered) subset. Errors: NOT_RUNNING, BAD_ARGUMENT (promptText without an accepting prompt policy, or oneShot without a policy to arm).electron_discover_runningScan the conventional CDP debug ports (9222-9225 by default) for already-running, debuggable Electron apps on loopback only. No session required. Returns: { ok, targets, count, scanned } where each target is { targetId, port, appName, pid } and scanned reports { host, ports, elapsed_ms } so an empty result is unambiguous. Errors: BAD_ARGUMENT (non-loopback host, invalid port list, or timeout outside bounds). A failed probe is simply "no target on that port".electron_doctorRun non-mutating preflight checks without starting an Electron session: Node version, Playwright, Electron, Linux display, configured app root and screenshot directory, eval policy, and project Electron runtime alignment. Returns: { ok, doctor_ok, checks, runtime }, where runtime includes server and, with --app-root, target Electron/Node/V8/ABI facts plus a bounded native-addon inventory. Inspect failed checks and warnings before electron_launch. Errors: none.electron_dragDrag the source element (ref or selector) onto the target element (targetRef or targetSelector), using the real mouse API. Options: force, timeoutMs. Returns: { ok, session_id, source, target }. Errors: SELECTOR_NO_MATCH / REF_NOT_FOUND (carries similar_refs), ELEMENT_NOT_VISIBLE (retryable), NOT_RUNNING, BAD_ARGUMENT (a side missing or both ref+selector given).electron_drop_fileSimulate dropping OS files onto the element identified by ref or selector. Web DataTransfer mode: reads each path on the host running the server, rebuilds the files in the renderer, and dispatches dragenter/dragover/drop with a real DataTransfer — engaging standard web drop handlers. Paths must be ABSOLUTE (max 10 files, 5242880 bytes each). default_prevented reports whether a drop handler engaged (called preventDefault); false usually means the target has no web drop handler. Apps that resolve dropped files to native OS paths need an app-specific IPC convention this tool does not simulate. Options: mimeType, timeoutMs. Returns: { ok, session_id, target, files, default_prevented }. Errors: ABSOLUTE_PATH_REQUIRED, FILE_NOT_FOUND, BAD_ARGUMENT (too many/large files, or ref+selector both), SELECTOR_NO_MATCH / REF_NOT_FOUND (carries similar_refs), NOT_RUNNING.- +43 more on the listing page
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
Capsulate
{
"mcpServers": {
"capsulate": {
"command": "npx",
"args": [
"-y",
"@capsulate/mcp"
],
"env": {
"CAPSULATE_API_KEY": "YOUR_CAPSULATE_API_KEY_HERE"
}
}
}
}
Core
{
"mcpServers": {
"core": {
"command": "npx",
"args": [
"-y",
"--package",
"@electron-stagewright/core@0.5.0",
"--package",
"playwright@1.61.1",
"--package",
"electron@42.3.0",
"electron-stagewright"
]
}
}
}
Frequently asked questions
Capsulate is categorized under OS Automation and uses a local stdio subprocess. Core belongs to OS Automation and uses a local stdio subprocess. Pick Capsulate for os automation work and Core for os automation.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
Capsulate has no declared pricing — check the project's own site. Core has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add capsulate and core as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, Capsulate has a quality signal of 61/100 (Good) with 1 views, 0 installs and 0 GitHub stars. Core has 57/100 (Good) with 1 views, 0 installs and 12 GitHub stars.
