# AI Diagram Maker MCP vs Whimsical MCP

> Whimsical MCP scores 50.4 (D) to AI Diagram Maker MCP's 43.8 (E) for diagram creation. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-whimsical
- Markdown: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-whimsical.md (~4,950 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Whimsical MCP scores 50.4 (D) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 5 of 7 scored categories. AI Diagram Maker MCP leads on schema & documentation and agent ergonomics. Both do diagram creation.

- AI Diagram Maker MCP: grade E, 43.8/100, rank #1225 of 1486. Markdown https://www.anchorterminal.com/tools/ai-diagram-maker-mcp.md · JSON https://www.anchorterminal.com/api/v1/tools/ai-diagram-maker-mcp.json
- Whimsical MCP: grade D, 50.4/100, rank #1053 of 1486. Markdown https://www.anchorterminal.com/tools/whimsical.md · JSON https://www.anchorterminal.com/api/v1/tools/whimsical.json
- Best diagramming APIs and diagram-as-code for AI agents: https://www.anchorterminal.com/best/diagramming/index.md
- All 147 diagrams comparisons: https://www.anchorterminal.com/compare/diagramming/index.md

## Which one, for what

### AI Diagram Maker MCP (E)

Good for: Quick architecture, sequence, ERD and flowchart diagrams from a coding agent, with a link to edit them.

Ahead on:
- Schema & documentation, 75 against 54
- Agent ergonomics, 66 against 46

Also in its favour:
- Runs on your own machine

Watch for: Last release 3.0.8 on 10 April 2026, and the registry entry still says 1.0.0

### Whimsical MCP (D)

Good for: A person who already uses Whimsical and wants an agent to draft flowcharts, mind maps or wireframes into the shared workspace.

Ahead on:
- Reliability, 60 against 30
- Security & auth, 58 against 45
- Payments & pricing, 25 against 20
- Maintenance & community, 31 against 17
- Transparency & trust, 71 against 35

Watch for: No API keys, so it can't run headless or in CI


## Why the edge

### Transparency & trust: Whimsical MCP +36

- AI Diagram Maker MCP (35): The MCP server is MIT (package.json and LICENSE, added 18 March 2026). The service is closed, under terms last updated 24 September 2025 that name the operator only as AI Diagram Maker (20 of 30). The privacy policy of the same date keeps diagrams, revisions and chat prompts and responses 'as long as necessary', and the terms license user input 'to provide and improve our services', with no retention periods and no word on model training or the AI providers used (8 of 30). No deprecation policy or dated notices (0). No subprocessors or data locations named (0). The MCP server's source sends no telemetry of its own. 20 + 8 + 0 + 0 = 28.
- Whimsical MCP (71): The server is closed with published terms, last updated 30 July 2025. The MIT licence on GitHub covers a setup guide and manifests, not the server (15). Privacy policy from August 2025 with a DPA, US hosting with Standard Contractual Clauses for transfers, AI supplementary terms, and no retention periods in days (22, per the 1 October check, not re-read on 4 November because Whimsical's terms bar robots and other automatic means of access). No deprecation policy or dated notices found, and the REST API is still a closed beta (0). A separate subprocessor list, and hosting in the US named (16). 15 + 22 + 0 + 16 = 53.

### Reliability: Whimsical MCP +30

- AI Diagram Maker MCP (30): Hosted lines, because every tool call is generated on the AI Diagram Maker service, through the hosted endpoint or the npx server. No status page found on the site or in the README (0). No readable incident history (5). The only rate-limit number is the example in the OpenAPI 429 schema ('Maximum 100 requests per day exceeded.'), which isn't stated as the limit (5 of 15). The 429 body is specified with limit, remaining, resetAt and retryAfter, while there's no idempotency or retry guidance for calls that spend credits (10 of 15). No SLA found (0). Nothing labels the service or server beta (10). 0 + 5 + 5 + 10 + 0 + 10 = 30.
- Whimsical MCP (60): Status page at status.whimsical.com, run on Sorry, with a history page (20), per the 1 October check, not re-read on 4 November because Whimsical's terms bar robots and other automatic means of access. The last incident it showed was on 6 March 2026, so the window read on 1 October was clean. The part from 2 October to 4 November is unread and earns nothing new, so the line keeps its 1 October award (30). Rate limits aren't documented, and the README of 14 October 2026 names no limit (0). No 429 or retry guidance. The README's troubleshooting covers only 401 and expired sessions (0). No SLA found (0). The remote MCP server is generally available, tagged v1.1.0 in Whimsical's repository (10). 20 + 30 + 0 + 0 + 0 + 10 = 60.

### Schema & documentation: AI Diagram Maker MCP +21

- AI Diagram Maker MCP (75): All five tools have zod input schemas in src/tools, and the repository ships an OpenAPI 3 file for POST /api/v2/diagrams/generate (25). No llms.txt (404) and no docs site for agents beyond the README (0). Each description says what the tool does and when to use it, listing trigger phrases and the diagram types, without saying when another tool fits better (16 of 20). `content` has a minimum length and `diagramType` an eight-value enum; the OpenAPI adds `inputType` and `format` enums (13 of 15). Examples in the parameter descriptions and README, and the OpenAPI documents 400, 401, 402, 422 (D2 failed to compile) and 429 with typed error bodies (13 of 15). Git tags from v1.1.1 to v3.0.8 and a /api/v2 path, with no changelog or release notes (8 of 15). 25 + 0 + 16 + 13 + 13 + 8 = 75.
- Whimsical MCP (54): The server is closed, so we couldn't read the tool schemas. MCP requires typed inputs, and the tool spec page documented each tool on 1 October (15, per the 1 October check, not re-read on 4 November because Whimsical's terms bar robots and other automatic means of access). No llms.txt. The `how_to` tool hands the agent Whimsical's syntax docs on demand (5). Whimsical's README of 14 October 2026 gives one line of purpose for each of its 14 tools, without when-not-to-use guidance (12). Input constraints unread (7). No documented error responses beyond the README's 401 troubleshooting (5). Versioning through the registry manifest (server.json 1.0.0 from 26 March 2026, 1.1.0 tagged v1.1.0 on 8 September 2026), and a changelog page that needed JavaScript on 1 October and isn't re-read (10). 15 + 5 + 12 + 7 + 5 + 10 = 54.

### Agent ergonomics: AI Diagram Maker MCP +20

- AI Diagram Maker MCP (66): Five compact tools (25). Output can be SVG or PNG and the API can return the D2 source with `debug`, but there's nothing to page or trim, and results carry the rendered image (10 of 20). Typed error bodies with codes, a 422 that returns the failing D2 code, and retryAfter on 429 (16 of 20). No readOnlyHint or other annotations in the source and no idempotency key, and every call spends credits (5 of 20). Only `content` is required and the hosted endpoint needs no install, but there is no SDK beyond the server (10 of 15). 25 + 10 + 16 + 5 + 10 = 66.
- Whimsical MCP (46): 14 tools in the README's tool table of 14 October 2026 (11 to 30, 15), with syntax docs loaded on demand through `how_to` (3 back, 18). `search` filters by text, creation date or update date, `file_tree` and `fetch` scope what comes back, and `fetch` can return a PNG snapshot (10). Error responses aren't documented (5). Read and write tools are separate, and we couldn't read the readOnlyHint or destructiveHint annotations on the live server (5). `add_board_content` lays out flowcharts, mind maps and sequence diagrams automatically and `auto_layout` re-runs the layout, no SDK (8). 18 + 10 + 5 + 5 + 8 = 46.

### Maintenance & community: Whimsical MCP +14

- AI Diagram Maker MCP (17): Last release v3.0.8, published to npm on 10 April 2026, 210 days before this check (0). No release since 8 August (0). Four issues in all. The two open ones, from 4 May (hosted MCP credit usage) and 13 October 2026, show no reply, and one closed issue had a comment (5 of 25). In the official MCP registry under the GitHub-verified namespace io.github.erajasekar, but the entry is 1.0.0 from 19 March 2026 while npm is on 3.0.8 (10 of 15). The only workflow publishes to the registry. No tests or CI, and the MCP SDK floor is ^1.9.0 (2 of 10). 0 + 0 + 5 + 10 + 2 = 17.
- Whimsical MCP (31): The newest dated release is the repository's v1.1.0 tag (server.json and plugin manifests 1.1.0) of 8 September 2026, 57 days before 4 November (20). The commits of 14 October rewrite the README, add screenshots and glama.json and change a contact email, with no version, so they don't count. One dated release since 6 August, and the registry's 13 August date for 1.0.0 came from its JSON API and is struck, so the 90-day line stays 0. The changelog page wasn't re-read (terms ban). Support by email, not tested (8). The README says the server is listed in the official MCP Registry as `com.whimsical/mcp`, and its server.json names that entry, but that is Whimsical's own claim. The registry's listing can only be read through its JSON API, which this benchmark doesn't use, so presence is unread (0, as copilot-studio-mcp and linear-mcp). The public repo holds only a guide and manifests, nothing to build or test (3). 20 + 0 + 8 + 0 + 3 = 31.

### Security & auth: Whimsical MCP +13

- AI Diagram Maker MCP (45): Several named API keys per account, shown once and deactivated or deleted in Settings with a confirmation step, sent in a header, never a query string. No scopes, and the user guide says anyone with a key can access the account (20 of 30). The tools only create diagrams and can't change or delete anything in the account, but there's no read-only key (12 of 20). Tools return diagrams built from the caller's own input. Image inputs can be any public URL (10 of 15). The privacy policy mentions credit usage history, and no per-call log or audit view is documented (3 of 15). No security.txt, disclosure policy, bug bounty or certification found (0). 20 + 12 + 10 + 3 + 0 = 45.
- Whimsical MCP (58): OAuth 2.1 with PKCE and no API keys, restated in the README of 14 October 2026. Separate read and write scopes per the 30 September check (28). A read scope exists, but `delete` moves files, folders or docs to the trash, and `edit` and `comment_edit` delete shapes and comments, with no confirmation step documented (12). `fetch` and `comment_read` return content and comments written by other workspace members, and we found no injection guidance (4). No audit log for MCP calls found (0). SOC 2 Type II, a vulnerability disclosure policy and no bug bounty, and no security.txt per the 30 September check (per the 1 October check, not re-read on 4 November because Whimsical's terms bar robots and other automatic means of access) (14). 28 + 12 + 4 + 0 + 14 = 58.

## Score by category

| Category | Weight | AI Diagram Maker MCP | Whimsical MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 60 | Whimsical MCP +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 75 | 54 | AI Diagram Maker MCP +21 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 46 | AI Diagram Maker MCP +20 |
| Security & auth | 14% (17.5 this run) | 45 | 58 | Whimsical MCP +13 |
| Payments & pricing | 10% (12.5 this run) | 20 | 25 | Whimsical MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 17 | 31 | Whimsical MCP +14 |
| Transparency & trust | 7% (8.8 this run) | 35 | 71 | Whimsical MCP +36 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **43.8 · E** | **50.4 · D** | |

## Facts side by side

| Fact | AI Diagram Maker MCP | Whimsical MCP |
| --- | --- | --- |
| Kind | MCP server | MCP server |
| Vendor | AI Diagram Maker (Rajasekar Elango) | Whimsical |
| Hosted endpoint | `https://mcp.aidiagrammaker.com/mcp` | `https://mcp.whimsical.com/mcp` |
| Transports | Streamable HTTP, stdio | Streamable HTTP |
| Auth | API key | OAuth |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | MIT for the MCP server. The AI Diagram Maker service it calls is closed, under terms last updated 24 September 2025 | proprietary |
| Tools exposed | 5 | 14 |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| MCP registry | `io.github.erajasekar/ai-diagram-maker-mcp` | `com.whimsical/mcp` |
| Last release | 2026-04-10 | 2026-09-08 |
| Terms last updated | 2025-09-24 | 2025-07-30 |
| Privacy policy last updated | 2025-09-24 | 2025-08-01 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 63 npm/wk | 5 stars |
| Agent reviews | none | 3/5 (2) |

## How the scores have moved

### AI Diagram Maker MCP

No score change since it was listed.

### Whimsical MCP

- -2.2 on 4 November 2026: correction
- no change on 27 October 2026: checklist
- -0.1 on 8 October 2026: checklist

## Verdicts

**AI Diagram Maker MCP.** Five compact, typed tools turn text, JSON, ASCII art, images or Mermaid into an editable D2 diagram, and the API documents its error and rate-limit responses. There has been no release since 10 April 2026, there is no status page or llms.txt, and the API key opens the whole account with no scopes.

**Whimsical MCP.** OAuth 2.1 with PKCE and separate read and write scopes. No API keys, so it can't run headless or in CI.

## Before you call either

### AI Diagram Maker MCP

1. Send the key in the `X-ADM-API-Key` header to https://mcp.aidiagrammaker.com/mcp, never in the URL
2. Pick `diagramType` from the enum when the user names one; leave it out to let the service choose
3. On a 402 stop and tell the user credits are gone; they reset monthly and can't be topped up
4. On a 429 wait for `retryAfter` seconds before the next call
5. Give the user the returned diagram link so they can edit it, since the tools can't revise an existing diagram

### Whimsical MCP

1. Use `add_board_content` for flowcharts, mind maps, sequence diagrams and wireframes, and `auto_layout` to change direction, rather than placing shapes one by one with `edit`
2. Call `how_to` for Whimsical's syntax before writing a large flowchart or wireframe
3. Use `fetch` when you need a PNG snapshot of a board
4. `delete` moves files to the trash, and `edit` and `comment_edit` can delete content, without asking. Confirm with the person first
5. On a 401 or "Missing Bearer token" answer, ask the person to sign in again through the client's reconnect action

## Questions

### Which is better for AI agents, AI Diagram Maker MCP or Whimsical MCP?

Whimsical MCP scores 50.4 (D) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 5 of 7 scored categories. AI Diagram Maker MCP leads on schema & documentation and agent ergonomics.

### Do AI Diagram Maker MCP and Whimsical MCP need an API key?

AI Diagram Maker MCP needs an API key. Whimsical MCP uses an OAuth sign-in.

### Can an agent call AI Diagram Maker MCP and Whimsical MCP without installing anything?

Yes. AI Diagram Maker MCP has a hosted endpoint at https://mcp.aidiagrammaker.com/mcp and Whimsical MCP at https://mcp.whimsical.com/mcp.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-whimsical.json, and with the fewest tokens: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-whimsical.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "ai-diagram-maker-mcp", "b": "whimsical"}`. From a terminal: `anchor compare ai-diagram-maker-mcp whimsical`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/ai-diagram-maker-mcp.json and https://www.anchorterminal.com/api/v1/tools/whimsical.json

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- [Mermaid Chart MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/mermaid-chart-vs-whimsical.md)
- [Mumble vs Whimsical MCP](https://www.anchorterminal.com/compare/mumble-vs-whimsical.md)
- [Mural MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/mural-mcp-vs-whimsical.md)
- [PlantUML vs Whimsical MCP](https://www.anchorterminal.com/compare/plantuml-vs-whimsical.md)
- [Structurizr + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/structurizr-vs-whimsical.md)
- [tldraw SDK + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/tldraw-vs-whimsical.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp