# AI Diagram Maker MCP vs Excalidraw

> Excalidraw scores 52.5 (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-excalidraw
- Markdown: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-excalidraw.md (~5,200 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

Excalidraw scores 52.5 (D) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 4 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
- Excalidraw: grade D, 52.5/100, rank #984 of 1486. Markdown https://www.anchorterminal.com/tools/excalidraw.md · JSON https://www.anchorterminal.com/api/v1/tools/excalidraw.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 65
- Agent ergonomics, 66 against 58

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

### Excalidraw (D)

Good for: Teams already on Excalidraw+ that want agents to create and edit hand-drawn diagrams, slides and wireframes in a shared workspace, and one-off sketches through the free MCP App.

Ahead on:
- Security & auth, 73 against 45
- Payments & pricing, 35 against 20
- Maintenance & community, 44 against 17
- Transparency & trust, 63 against 35

Also in its favour:
- Open source

Watch for: The API and MCP server are in public beta. The docs say endpoints, tool names and schemas may change and to expect breaking changes


## Why the edge

### Security & auth: Excalidraw +28

- 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.
- Excalidraw (73): API keys are workspace-bound, take `read` or `full` permission or specific routes, carry an expiry and can be rotated or soft-deleted. Personal and workspace keys differ in access to private collections (30). Read-only keys expose only read tools and deletes go to trash, with no confirmation step found (14). Scene text written by collaborators returns to the model and `add_image` fetches a public URL, with no injection guidance found (3). `GET /logs` returns the workspace audit log with filters by user, action and operation (13). Excalidraw states SOC 2 Type 1 and Type 2, yearly penetration tests and Vanta scanning, and publishes advisories on GitHub (OSV lists five for the editor, the newest on 24 April 2026). That newest one, GHSA-39h7-pwv7-rc3x, covers Mermaid's own sequence-diagram flaw (CVE-2025-54881, published by Mermaid on 19 August 2025), fixed in 0.18.1 by a dependency update, so it takes no deduction; the other four are older than twelve months. No security.txt, bug bounty or SECURITY.md was found, and the trust centre report was not read (13). Docs readings per the 9 October check, not re-read on 4 November. 30 + 14 + 3 + 13 + 13 = 73.

### Transparency & trust: Excalidraw +28

- 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.
- Excalidraw (63): The graded service is closed under public terms of use, while the editor and the MCP App are MIT (20). The privacy policy of 29 April 2021 says servers are in the United States and data is kept at most one month after an account ends. The DPA of 13 January 2026 says cancelling a subscription does not delete data and retention follows internal policies. Neither names AI providers (14). No deprecation policy, only the beta warning that contracts may break (3). The DPA points to a sub-processor list at trust.excalidraw.com, which is script-drawn and was not read, and says some sub-processors are in the United States (8). The terms were re-read on 4 November (published 30 May 2022, in effect 1 June 2022); the other documents per the 9 October check. 20 + 14 + 3 + 8 = 45.

### Maintenance & community: Excalidraw +27

- 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.
- Excalidraw (44): The newest changelog entry is dated 1 September 2026, 64 days before this check, per the 9 October reading (20); the changelog wasn't re-read on 4 November (terms ban automated access). The editor package `@excalidraw/excalidraw` has no release since 0.18.1 (20 April 2026), and the MCP App's newest tag is v0.3.2 (9 February 2026), both read from clones. Of the dated entries recorded, only 1 September falls in the 90 days from 6 August (0). A public changelog, a roadmap, a Discord server and support@excalidraw.com exist, and the editor repository had commits up to 3 November 2026 (12). There is no SDK for the API, and the editor package on npm is the vendor's only official package (5). The editor repository runs test, lint and size workflows, and the MCP App repository has no CI and no commit since 24 March 2026 (7). 20 + 0 + 12 + 5 + 7 = 44.

### Payments & pricing: Excalidraw +15

- AI Diagram Maker MCP (20): No x402, MPP or L402 (0). Plan prices are public (Plus $10, Max $20 a month), with credits counted at 1,000 tokens each, so there's no per-diagram price (10 of 20). Basic is free forever with 50 credits a month, but the page doesn't say whether a card is needed or whether API and MCP calls are included (10 of 20, half as with an unstated card rule). A person signs up in the app and creates the key (0). 0 + 10 + 10 + 0 = 20.
- Excalidraw (35): No x402, MPP or L402 (0). Plan prices are public, Free at $0 and Plus at $6 a user a month, with no per-call price (10). The free editor and the keyless MCP App need no card, while the API needs the Plus plan, whose 14-day trial does not say whether a card is taken; the terms (re-read 4 November) say the account is charged when the trial ends (15). The MCP App's README gives https://mcp.excalidraw.com as a remote server to add as a custom connector, with no key, but an API key is created by a person in workspace settings (10). Pricing per the 9 October check, not re-read on 4 November. 0 + 10 + 15 + 10 = 35.

### Schema & documentation: AI Diagram Maker MCP +10

- 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.
- Excalidraw (65): The endpoint reference is generated from an OpenAPI schema, but no file is linked from the docs, and the MCP tool definitions could not be read without a key (10). `llms.txt` and `llms-full.txt` are published (10). The tools page says when to use `search_scene_content` over `get_scene_content`, `label` over `text` and `create_diagram` over `edit_scene_content` (16). Parameters carry ranges and enums in the reference, while `edit_scene_content` takes its elements as a JSON array string (9). Each endpoint has samples in six languages and error bodies for 400, 401 and 403 (12). The path is versioned as `/api/v1` and a monthly product changelog carries API and MCP items, with no API changelog of its own (8). Per the 9 October check, not re-read on 4 November (terms ban automated access). 10 + 10 + 16 + 9 + 12 + 8 = 65.

### Agent ergonomics: AI Diagram Maker MCP +8

- 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.
- Excalidraw (58): The docs list 37 MCP tools (5). The server shows a key only the tools its routes allow, so a read-only or route-restricted key cuts the list (7). Lists take `offset` and `limit` up to 100, logs take a cursor and filters, and `search_scene_content` returns only matching elements (18). Errors are JSON with `statusCode`, `error` and `message`, and seven status codes are documented (13). No idempotency keys. Deletes of scenes and collections move them to trash, and MCP annotations could not be read (8). `create_diagram` measures labels and routes arrows, but there is no SDK for the API (7). Per the 9 October check, not re-read on 4 November. 5 + 7 + 18 + 13 + 8 + 7 = 58.

## Score by category

| Category | Weight | AI Diagram Maker MCP | Excalidraw | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 30 | even |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 75 | 65 | AI Diagram Maker MCP +10 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 58 | AI Diagram Maker MCP +8 |
| Security & auth | 14% (17.5 this run) | 45 | 73 | Excalidraw +28 |
| Payments & pricing | 10% (12.5 this run) | 20 | 35 | Excalidraw +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 17 | 44 | Excalidraw +27 |
| Transparency & trust | 7% (8.8 this run) | 35 | 63 | Excalidraw +28 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **43.8 · E** | **52.5 · D** | |

## Facts side by side

| Fact | AI Diagram Maker MCP | Excalidraw |
| --- | --- | --- |
| Kind | MCP server | HTTP API |
| Vendor | AI Diagram Maker (Rajasekar Elango) | Excalidraw s.r.o. |
| Hosted endpoint | `https://mcp.aidiagrammaker.com/mcp` | `https://api.excalidraw.com/api/v1/mcp` |
| Transports | Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | API key | API key |
| 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 | Excalidraw+ is a proprietary service under Excalidraw's terms of use. The editor and the MCP App on GitHub are MIT |
| Tools exposed | 5 | 37 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | `io.github.erajasekar/ai-diagram-maker-mcp` | not listed |
| Last release | 2026-04-10 | 2026-09-01 |
| Terms last updated | 2025-09-24 | no date given |
| Privacy policy last updated | 2025-09-24 | 2021-04-29 |
| 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 | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 63 npm/wk | 134k stars, 676k npm/wk |

## How the scores have moved

### AI Diagram Maker MCP

No score change since it was listed.

### Excalidraw

- -2.0 on 4 November 2026 (C to D): new evidence, correction
- -0.1 on 28 October 2026: correction
- +0.1 on 28 October 2026: new evidence

## 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.

**Excalidraw.** Excalidraw+ keys carry read or full permission, route restrictions and an expiry, and the MCP server shows a key only the tools its routes allow. The API and MCP server are in public beta with breaking changes expected, sit behind the $6 Plus plan, and have no published OpenAPI file, SDK or idempotency keys. No status history can be read.

## 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

### Excalidraw

1. Send `Authorization: Bearer <API_KEY>` to https://api.excalidraw.com/api/v1. For MCP, use `POST /api/v1/mcp` only. The server is stateless and answers 405 to other methods
2. Use a personal key to reach the owner's private collection with the collection ID `private`. A workspace admin must enable personal keys first
3. Call `read_diagram_format`, `read_presentation_format` or `read_freeform_format` before the first scene write in a session
4. Write with `edit_scene_content` and bind arrows through `startBinding` and `endBinding` with `tempId` references. `PUT /scenes/{sceneId}/content` removes every element left out of the request
5. Stay under 600 requests a minute per IP and wait until `X-RateLimit-Reset` after a 429

## Questions

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

Excalidraw scores 52.5 (D) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 4 of 7 scored categories. AI Diagram Maker MCP leads on schema & documentation and agent ergonomics.

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

Both need an API key.

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

Yes. AI Diagram Maker MCP has a hosted endpoint at https://mcp.aidiagrammaker.com/mcp and Excalidraw at https://api.excalidraw.com/api/v1/mcp.

### Are AI Diagram Maker MCP and Excalidraw open source?

No open-source release is listed for AI Diagram Maker MCP. Excalidraw is open source (Excalidraw+ is a proprietary service under Excalidraw's terms of use. The editor and the MCP App on GitHub are MIT).


## For agents

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

## Other comparisons with AI Diagram Maker MCP or Excalidraw

- [AI Diagram Maker MCP vs Cloudviz API](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-cloudviz.md)
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- [AI Diagram Maker MCP vs Mumble](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-mumble.md)
- [AI Diagram Maker MCP vs Mural MCP](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-mural-mcp.md)
- [AI Diagram Maker MCP vs PlantUML](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-plantuml.md)
- [AI Diagram Maker MCP vs Structurizr + MCP](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-structurizr.md)
- [AI Diagram Maker MCP vs tldraw SDK + MCP](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-tldraw.md)
- [AI Diagram Maker MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-whimsical.md)
- [Cloudviz API vs Excalidraw](https://www.anchorterminal.com/compare/cloudviz-vs-excalidraw.md)
- [Diagrams.so API + MCP vs Excalidraw](https://www.anchorterminal.com/compare/diagrams-so-vs-excalidraw.md)
- [draw.io + MCP vs Excalidraw](https://www.anchorterminal.com/compare/drawio-vs-excalidraw.md)
- [Eraser API + MCP vs Excalidraw](https://www.anchorterminal.com/compare/eraser-vs-excalidraw.md)
- [ExcaliClaw vs Excalidraw](https://www.anchorterminal.com/compare/excaliclaw-vs-excalidraw.md)
- [Excalidraw vs Kroki](https://www.anchorterminal.com/compare/excalidraw-vs-kroki.md)
- [Excalidraw vs Lucid API + MCP](https://www.anchorterminal.com/compare/excalidraw-vs-lucid.md)
- [Excalidraw vs Mermaid Chart MCP](https://www.anchorterminal.com/compare/excalidraw-vs-mermaid-chart.md)
- [Excalidraw vs Mumble](https://www.anchorterminal.com/compare/excalidraw-vs-mumble.md)
- [Excalidraw vs Mural MCP](https://www.anchorterminal.com/compare/excalidraw-vs-mural-mcp.md)
- [Excalidraw vs PlantUML](https://www.anchorterminal.com/compare/excalidraw-vs-plantuml.md)
- [Excalidraw vs Structurizr + MCP](https://www.anchorterminal.com/compare/excalidraw-vs-structurizr.md)
- [Excalidraw vs tldraw SDK + MCP](https://www.anchorterminal.com/compare/excalidraw-vs-tldraw.md)
- [Excalidraw vs Whimsical MCP](https://www.anchorterminal.com/compare/excalidraw-vs-whimsical.md)
- [D2 vs Excalidraw](https://www.anchorterminal.com/compare/d2-vs-excalidraw.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