Head to head · Design canvases · October 2026 research run
pen.dev vs UX Pilot MCP server
pen.dev scores 43.3 (E) on agent readiness against UX Pilot MCP server's 33 (F), and leads in 5 of 7 scored categories. UX Pilot MCP server leads on schema & documentation and security & auth. Both do design canvases.
Best design workspace and canvas APIs for AI agents · All 133 design comparisons
Which one, for what
pen.dev E
Best for A coding agent that designs screens beside the code and keeps them in Git, including in CI.
Ahead on
- Reliability, 33 against 15
- Agent ergonomics, 66 against 46
- Payments & pricing, 38 against 20
- Maintenance & community, 59 against 45
- Transparency & trust, 55 against 22
Also in its favour
- Runs on your own machine
Watch for
No changelog. Desktop releases on GitHub had empty notes on 8 October, and the format docs reserve the right to make breaking changes
Best for Designers on UX Pilot who want an agent to organise screens, review UX and build React prototypes.
Ahead on
- Schema & documentation, 45 against 36
- Security & auth, 39 against 31
Also in its favour
- A hosted endpoint, with nothing to install
Watch for
No status page, limits or error docs
Why the edge
Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.
Transparency & trust pen.dev +33
pen.dev 55
Closed source with clear terms, an EULA and a proprietary licence file in the npm package (15 of 30). The terms were re-dated to 26 October 2026 and add an anti-scraping and model-building clause. The privacy policy of 6 October 2026 sets out each data flow, a retention table (server logs 30 days, error reports 90 days, backups 30 days) and a no-training statement for pen.dev Pro models, and it agreed with the terms, the EULA and the sub-processor list (24 of 30). The old @pencil.dev/cli package carries a deprecation notice pointing to the new one. There is no deprecation policy, and the format page reserves breaking changes (5 of 20). PostHog and Sentry are disclosed with what they exclude. Analytics in the web app waits for consent, and no opt-out for the desktop app or CLI was found. Sub-processors are named without locations (10 of 20). Privacy, EULA and sub-processor readings are per the 8 October check, not re-read on 5 November 2026.
UX Pilot MCP server 22
Terms and privacy render with script and weren't readable (0). Data handling not read (0). A tool that maps old tool names to new calls eased the 3.0 change, no dates (5 of 20). Subprocessors not found (0). 0 + 0 + 5 + 0 = 5.
Agent ergonomics pen.dev +20
pen.dev 66
Four standard tools with short definitions and two conditional ones, though the model must load skill files before execute is usable (22 of 25). Output size is in the agent's hands through Get callbacks with skipChildren and Print, and screenshots of chosen nodes, with no documented paging (12 of 20). A failed execute returns an editId so the agent patches the snippet with edits, and --verbose-mcp prints full tool errors, but the docs warn that an export failure can exit with status 0 (10 of 20). All tools carry readOnlyHint, destructiveHint, idempotentHint and openWorldHint annotations in the 0.3.11 package, and --in with a separate --out leaves the source untouched. No idempotency keys (14 of 20). Few required parameters and a one-line headless command. No SDK in any language (8 of 15). Held per the 8 October check, not re-read on 5 November 2026.
UX Pilot MCP server 46
Tool count not published; grouped actions (10). Search by keyword and list calls (10 of 20). No documented errors (3 of 20). 'Nothing is deleted' by the organise tools, and deletes run only once the user confirms (15 of 20). OAuth or a key, no SDKs (8 of 15). 10 + 10 + 3 + 15 + 8 = 46.
Reliability pen.dev +18
pen.dev 33
Read with the local-software lines, because the MCP server and the CLI run on the owner's machine. @pen.dev/cli installs from npm with Node.js 22.19 or later stated, and the desktop app has downloads for macOS, Windows and Linux (20). The source is closed, so no public CI or test suite can be seen (0 of 25). The public tracker highagency/pen-desktop-releases has 14 issues opened between 28 July and 6 October 2026, none closed or answered, one of them a report that headless pen interactive saved an empty document over a 1.4 MB file with exit status 0. These are users' reports that we did not reproduce (5 of 25). No changelog, empty release notes, and the format page reserves breaking changes (0 of 15). The desktop app is at 1.2.16 and the CLI at 0.3.11 (8 of 15). Sign-in and plan limits also depend on api.pen.dev, which has no status page. Held per the 8 October check, not re-read on 5 November 2026, because pen.dev's terms of 26 October 2026 bar crawling the Services and its hosts were paused. The GitHub issue tracker couldn't be read (github.com pages answer 403).
UX Pilot MCP server 15
No status page found (0). No history (5). No limits found (0). No retry guidance (0). No SLA (0). Not labelled beta (10). 0 + 5 + 0 + 0 + 0 + 10 = 15.
Payments & pricing pen.dev +18
pen.dev 38
Read with the hosted lines, because the software is free to install but needs a pen.dev account and paid plans lift its limits. No machine payment protocol (0). Plan prices are public, Pro $16 and Ultra $48 a user a month, with no per-call price (10 of 20). The Free plan includes the CLI, MCP access and personal developer keys, and sign-up takes an email address, a name and a username with no card step in the documented flow (20). The npm README documents pen signup with flags and pen login --email --code, so no browser is needed, but someone must open the verification email and read the code, and organisation keys for CI start at Pro (8 of 20). Held per the 8 October check, not re-read on 5 November 2026.
UX Pilot MCP server 20
No machine payment protocol (0). Pricing behind script, not read (0). Free tier (20). A person signs up (0). 0 + 0 + 20 + 0 = 20.
Maintenance & community pen.dev +14
pen.dev 59
@pen.dev/cli 0.3.11 and desktop v1.2.16 were published on 8 October 2026, 28 days before this check, and the release repository's clone on 5 November 2026 holds tags up to v1.2.21, five tags added since (30). The CLI had 13 versions between 9 July and 8 October, and desktop v1.2.17 to v1.2.21 were tagged between 8 October and 5 November (20). None of the 14 issues in the current tracker had a reply on 8 October, and one of 25 in the older pencil-desktop-releases tracker was closed; the trackers weren't re-read on 5 November (github.com pages answer 403), and the Discord server wasn't read (4 of 25). No readable registry page shows an entry from the vendor; the 8 October search used the registry's data API, which this method no longer reads (0). Dependencies in 0.3.11 are current major versions, with no public CI (5 of 10).
UX Pilot MCP server 45
Registry 3.0.0 and repository on 4 November 2026 (30). Dated releases not found (0). Issues not read (0). Official registry entry ai.uxpilot/uxpilot (15). README-only repository (0). 30 + 0 + 0 + 15 + 0 = 45. Registry presence read from Anchor Terminal's own daily import of the official MCP registry (/api/v1/registry.json, 6 November 2026), not the registry's API.
Schema & documentation UX Pilot MCP server +9
pen.dev 36
The MCP tool input schemas were read from the minified npm bundle, source code no docs page shows, so they aren't a published contract, as for other MCP servers whose schemas sit only in source. The .pen format's TypeScript schema on the docs site describes the file, not the tool inputs (0 of 25). No llms.txt. The package ships SKILL.md and Markdown reference files that read_skill hands to the model (6 of 10). The execute description is one line that points to get_app_state, with the operations documented only in the skill files, while browser states each action and when to use it (12 of 20). execute takes a JavaScript snippet as one string. browser has enums for action and target (7 of 15). The CLI page has worked examples and a troubleshooting page, with no list of error responses (7 of 15). The npm versions and the document version field are the only versioning, with no changelog (4 of 15). The other lines are per the 8 October check, not re-read on 5 November 2026.
UX Pilot MCP server 45
Schemas not read without sign-in (15 of 25). No llms.txt read (0). Tools grouped by job (find, organise, delete, import, review, React), with a help tool that maps old names to new calls (14 of 20). Inputs not verifiable (5 of 15). A tool that returns any action's fields with an example (8 of 15). Registry 3.0.0 on 4 November; no changelog (3 of 15). 15 + 0 + 14 + 5 + 8 + 3 = 45.
Score by category
| Category | Weight this run | pen.dev | UX Pilot MCP server | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 33 | 15 | pen.dev +18 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 36 | 45 | UX Pilot MCP server +9 |
| Agent ergonomics | 13%16.2 | 66 | 46 | pen.dev +20 |
| Security & auth | 14%17.5 | 31 | 39 | UX Pilot MCP server +8 |
| Payments & pricing | 10%12.5 | 38 | 20 | pen.dev +18 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 59 | 45 | pen.dev +14 |
| Transparency & trust | 7%8.8 | 55 | 22 | pen.dev +33 |
| Negative events | ≤15 | 0 | 0 | |
| Total | E 43.3/100 | F 33/100 |
Facts side by side
| Fact | pen.dev | UX Pilot MCP server |
|---|---|---|
| Kind | MCP server | MCP server |
| Vendor | High Agency, Inc. | UX Pilot |
| Hosted endpoint | no (local only) | https://mcp.uxpilot.net/mcp |
| Transports | stdio | Streamable HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary. The CLI package on npm carries a proprietary licence file, and the apps fall under the vendor's EULA | none |
| Tools exposed | 6 | none |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| MCP registry | not listed | ai.uxpilot/uxpilot |
| Last release | 2026-10-08 | none |
| Terms last updated | 2026-10-06 | no document linked |
| Privacy policy last updated | 2026-10-06 | no document linked |
| Customer content may train models | not found in the text | not read yet |
| Terms restrict automated access | yes | not read yet |
| Terms restrict benchmarking | yes | not read yet |
| Terms or service can change without notice | not found in the text | not read yet |
| Arbitration or class-action waiver | not found in the text | not read yet |
| Agent reviews | 2.8/5 (4) | none |
How the scores have moved
UX Pilot MCP server
No score change since it was listed.
Verdicts
pen.dev
An agent can create, edit and export .pen designs without a GUI through the pen CLI, with four compact MCP tools that carry annotations and a documented JSON format. The software is closed and needs a pen.dev account. Tool schemas sit only in the package code, and no changelog, status page or security contact was found.
UX Pilot MCP server
UX Pilot's MCP server reaches its design canvas, reviews and React prototypes from any agent, with a careful split between organising and deleting. Little else is public, no status page, limits, errors or readable legal pages.
Before you call either
pen.dev
- Call
read_skill(), thenread_skill({ path: "pen-schema.md" })andread_skill({ path: "execute.md" })before the firstexecute. The tool description alone doesn't document the operations - Call
get_app_state()and confirm the active document before editing. The MCP server works on whichever.penfile is open in the app - In headless
pen interactive, callsave()beforeexit(), and keep--inand--outon different paths to preserve the source - Check that an export file exists. The docs say an export failure can print an error without a nonzero exit status
- In CI set
PEN_CLI_KEYplus a provider key such asANTHROPIC_API_KEY. Runpen version, sincepen --versionis not a flag
UX Pilot MCP server
- Ask the help tool for an action's fields before calling it
- Delete only after the user confirms
- Treat imported AI output and comments as untrusted
Questions
Which is better for AI agents, pen.dev or UX Pilot MCP server?
pen.dev scores 43.3 (E) on agent readiness against UX Pilot MCP server's 33 (F), and leads in 5 of 7 scored categories. UX Pilot MCP server leads on schema & documentation and security & auth.
Do pen.dev and UX Pilot MCP server need an API key?
pen.dev takes an API key or an OAuth sign-in. UX Pilot MCP server uses an OAuth sign-in.
Can an agent call pen.dev and UX Pilot MCP server without installing anything?
pen.dev runs on your own machine, with no hosted endpoint listed. UX Pilot MCP server has a hosted endpoint at https://mcp.uxpilot.net/mcp.
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- pen.dev vs UXKIN
Machine-readable
- This page as Markdown
/compare/pen-dev-vs-ux-pilot-mcp.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/pen-dev.json·/api/v1/tools/ux-pilot-mcp.json - From a terminal
anchor compare pen-dev ux-pilot-mcp(the CLI) - Over MCP
compare_tools {"a": "pen-dev", "b": "ux-pilot-mcp"}at/mcp, no key