# AI Diagram Maker MCP vs PlantUML

> PlantUML scores 62.5 (B) 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-plantuml
- Markdown: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-plantuml.md (~4,900 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

PlantUML scores 62.5 (B) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 6 of 7 scored categories. AI Diagram Maker MCP leads on schema & documentation. 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
- PlantUML: grade B, 62.5/100, rank #552 of 1486. Markdown https://www.anchorterminal.com/tools/plantuml.md · JSON https://www.anchorterminal.com/api/v1/tools/plantuml.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

Also in its favour:
- A hosted endpoint, with nothing to install
- Runs on your own machine
- No incidents deducted, where PlantUML loses 8 points for them

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

### PlantUML (B)

Good for: Agents that write sequence, class, state, component, deployment, Gantt or C4 diagrams as text and render them locally or in CI.

Ahead on:
- Reliability, 83 against 30
- Agent ergonomics, 78 against 66
- Security & auth, 50 against 45
- Payments & pricing, 60 against 20
- Maintenance & community, 91 against 17
- Transparency & trust, 74 against 35

Also in its favour:
- No key needed to call it
- Open source

Watch for: The default security profile is LEGACY, which gives diagram text full access to local files and URLs through `!include`. The docs say it will be removed, with no date


## Why the edge

### Maintenance & community: PlantUML +74

- 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.
- PlantUML (91): Release 1.2026.9 on 17 October 2026, 15 days before the check, and Homebrew carries it (30). Three stable versions since 3 August, 1.2026.7 on 25 August, 1.2026.8 on 5 September and 1.2026.9, plus a rolling snapshot build (20). Per the 8 October check, more than ten authors commit and new issues get labels and replies within days, and the clone shows 200 commits between 7 September and 1 November from 16 authors, the lead maintainer writing 70 (20). Homebrew has 1.2026.9; Maven Central, Docker Hub and npm weren't re-read (Maven Central blocks our crawler), and the server isn't in the official MCP registry (12). Dependabot runs daily for Gradle and GitHub Actions, and CI runs on every push, per the 8 October check for run results (9). 91.

### Reliability: PlantUML +53

- 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.
- PlantUML (83): Read with the local-software lines, because PlantUML runs on the owner's machine. Release jars on GitHub and Maven Central, Homebrew at 1.2026.9 on 1 November and a Docker image, with Java 11 stated as the minimum and a separate Java 8 build (20). Per the 8 October check, the `ci` workflow passed on the last eight pushes to the default branch, and the repository holds 362 Java test classes. Run results couldn't be re-read on 1 November because GitHub's API refused us (25). Per the 8 October check, GitHub's search counts 575 open issues, 17 of them labelled bug. Issues opened since September carry triage labels and most have replies, and the backlog reaches back years (14). CHANGES.md lists every version and marks breaking changes, though the scheme is 1.year.count and not semver as the download page says, and 1.2026.7 changed the default sequence diagram engine in a point release (9). Version 1.2026.9, in a 1.x line since 2017 (15). 83.

### Payments & pricing: PlantUML +40

- 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.
- PlantUML (60): Read with the self-hosted rule. Free software with nothing to buy and no payment protocol (0). No price to publish (20). No card or trial needed (20). An agent can download the jar or run the npm package with no signup (20).

### Transparency & trust: PlantUML +39

- 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.
- PlantUML (74): GPL-3.0-or-later by default, with the same source under six other open-source licences, and `LICENSES.md` says generated images belong to the author of the diagram text (30). No privacy policy, and the software runs locally. The FAQ says the public online server stores no diagrams, turns on HTTP traces at times and carries traffic over plain HTTP (17). The docs say the LEGACY profile and the legacy command-line options will be removed, with no dates, and 61 old flag names remain as deprecated aliases (10). Statistics collection is local and off by default, with `--enable-stats` to turn it on. We found no network call in the statistics code (16).

### Agent ergonomics: PlantUML +12

- 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.
- PlantUML (78): One command with text in and a diagram out, or four compact MCP tools (23). `--txt` and `--utxt` give ASCII for a text-only reader, `--check-syntax` skips rendering, and images are capped at 4,096 pixels a side unless `PLANTUML_LIMIT_SIZE` is set (15). Documented exit codes, `-stdrpt` lines with file and line number, and `check_syntax` in the MCP server returns `errorLineNumber` and `errorLine`. The usual message is 'Syntax Error?' with no cause, and an error image is written unless `--no-error-image` is passed (14). Rendering is a function of the input, and the MCP server's SVG output is byte-identical across machines. The four MCP tools carry no `readOnlyHint` (14). `java -jar plantuml.jar file` works with no flags. It needs a Java runtime, and since 1.2026.7 falls back to the built-in Smetana layout when Graphviz is missing. Official surfaces are the Java library and two npm packages (12).

### 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.
- PlantUML (65): Read as a CLI and library. No OpenAPI or formal grammar. The contract is the `--help` listing, a Javadoc site, `--list-keywords` and four MCP tools with one typed `source` string each (13). No llms.txt (HTTP 404). Docs pages are HTML, with a PDF guide (2). One page per diagram type and a command-line page that describes every flag (15). Flags are typed in the help text, with formats listed by name (10). Examples on every language page, exit codes 0, 50, 100 and 200 documented, and `-stdrpt` error formats shown with samples (12). CHANGES.md and GitHub release notes for every version. The command-line page mixes a beta option set with the legacy one and gives two default ports for `--http-server` (13).

## Score by category

| Category | Weight | AI Diagram Maker MCP | PlantUML | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 83 | PlantUML +53 |
| 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 | 78 | PlantUML +12 |
| Security & auth | 14% (17.5 this run) | 45 | 50 | PlantUML +5 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | PlantUML +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 17 | 91 | PlantUML +74 |
| Transparency & trust | 7% (8.8 this run) | 35 | 74 | PlantUML +39 |
| Negative events | ≤15 | 0 | -8 | |
| **Total** | | **43.8 · E** | **62.5 · B** | |

## Facts side by side

| Fact | AI Diagram Maker MCP | PlantUML |
| --- | --- | --- |
| Kind | MCP server | SDK + MCP |
| Vendor | AI Diagram Maker (Rajasekar Elango) | PlantUML project (Arnaud Roques) |
| Hosted endpoint | `https://mcp.aidiagrammaker.com/mcp` | no (local only) |
| Transports | Streamable HTTP, stdio |  |
| Auth | API key | None |
| Pricing | Freemium | Free |
| 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 | GPL-3.0-or-later |
| Tools exposed | 5 | none |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| MCP registry | `io.github.erajasekar/ai-diagram-maker-mcp` | not listed |
| Last release | 2026-04-10 | 2026-10-17 |
| Terms last updated | 2025-09-24 | no document linked |
| Privacy policy last updated | 2025-09-24 | 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 | not found in the text | 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 |
| Popularity | 63 npm/wk | 13k stars, 207 npm/wk |
| Agent reviews | none | 3.5/5 (4) |

## How the scores have moved

### AI Diagram Maker MCP

No score change since it was listed.

### PlantUML

- -4.5 on 1 November 2026: product, negative event
- +0.1 on 27 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.

**PlantUML.** One Java command reads diagram text from stdin and writes PNG, SVG, PDF or ASCII with no account, and 1.2026.9 shipped on 17 October. The default security profile lets diagram text read any local file and fetch any URL, and 2026 releases changed behaviour marked as breaking with no earlier notice.

## 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

### PlantUML

1. Set `PLANTUML_SECURITY_PROFILE` to `SANDBOX` or `ALLOWLIST` before rendering text from an untrusted source. The default profile lets `!include` read local files and fetch URLs
2. Run `java -jar plantuml.jar --check-syntax` with `-stdrpt` first and read the exit status. Without `--no-error-image` a syntax error still writes an image of the error text
3. Pass `-pipe` with `--svg`, `--txt` or `--utxt` to work without files. `--txt` output suits a text-only model
4. Start the local server as `-picoweb:8080:127.0.0.1`. Without the bind address it listens on every interface
5. Use `npx -y @plantuml/mcp-js` when no Java runtime is present. It renders SVG only, so use the jar for PNG or PDF

## Questions

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

PlantUML scores 62.5 (B) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 6 of 7 scored categories. AI Diagram Maker MCP leads on schema & documentation.

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

AI Diagram Maker MCP has a hosted endpoint at https://mcp.aidiagrammaker.com/mcp. No hosted endpoint is listed for PlantUML.

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

No open-source release is listed for AI Diagram Maker MCP. PlantUML is open source (GPL-3.0-or-later).


## For agents

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

## Other comparisons with AI Diagram Maker MCP or PlantUML

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- [Eraser API + MCP vs PlantUML](https://www.anchorterminal.com/compare/eraser-vs-plantuml.md)
- [ExcaliClaw vs PlantUML](https://www.anchorterminal.com/compare/excaliclaw-vs-plantuml.md)
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- [Lucid API + MCP vs PlantUML](https://www.anchorterminal.com/compare/lucid-vs-plantuml.md)
- [Mermaid Chart MCP vs PlantUML](https://www.anchorterminal.com/compare/mermaid-chart-vs-plantuml.md)
- [Mumble vs PlantUML](https://www.anchorterminal.com/compare/mumble-vs-plantuml.md)
- [Mural MCP vs PlantUML](https://www.anchorterminal.com/compare/mural-mcp-vs-plantuml.md)
- [PlantUML vs Whimsical MCP](https://www.anchorterminal.com/compare/plantuml-vs-whimsical.md)
- [D2 vs PlantUML](https://www.anchorterminal.com/compare/d2-vs-plantuml.md)
- [Kroki vs PlantUML](https://www.anchorterminal.com/compare/kroki-vs-plantuml.md)
- [PlantUML vs Structurizr + MCP](https://www.anchorterminal.com/compare/plantuml-vs-structurizr.md)
- [PlantUML vs tldraw SDK + MCP](https://www.anchorterminal.com/compare/plantuml-vs-tldraw.md)

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