# uml.singsk.com PlantUML (remote · uml.singsk.com)

Render, validate, encode/decode PlantUML diagram-as-code; 22 diagram types. Free, no auth.

- Trust score: 78/100 (medium)
- Change this week: 0
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `uml.singsk.com`: 78/100 (this document), [markdown](https://verifymcp.io/servers/com-singsk-uml-plantuml/uml.md), [page](https://verifymcp.io/servers/com-singsk-uml-plantuml/uml)

## Channel facts

- Endpoint: `https://uml.singsk.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.1.0.2`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 6 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 79/100
  - AI-judged instruction clarity (excellent).
  - Tool/resource definitions use about 669 tokens (~111/item across 6 items; 6 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 100/100
  - No destabilizing schema changes in the last 30 days.
- **Tool Coverage**: 83/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 50% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 6 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 7 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 60/100
  - Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28.

## Install

### How do I install the uml.singsk.com PlantUML MCP server?

uml.singsk.com PlantUML is a hosted endpoint at https://uml.singsk.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http com-singsk-uml-plantuml 'https://uml.singsk.com/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "com-singsk-uml-plantuml": {
      "url": "https://uml.singsk.com/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "com-singsk-uml-plantuml": {
      "type": "http",
      "url": "https://uml.singsk.com/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.com-singsk-uml-plantuml]
url = "https://uml.singsk.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-singsk-uml-plantuml": {
      "type": "remote",
      "url": "https://uml.singsk.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-singsk-uml-plantuml --url 'https://uml.singsk.com/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-singsk-uml-plantuml:
    url: "https://uml.singsk.com/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "com-singsk-uml-plantuml": {
      "Transport": "http",
      "Url": "https://uml.singsk.com/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add com-singsk-uml-plantuml -t streamable-http -u 'https://uml.singsk.com/mcp'
```

### Other

```json
{
  "mcpServers": {
    "com-singsk-uml-plantuml": {
      "type": "http",
      "url": "https://uml.singsk.com/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-05 (score 78, 0)

- [security] Stability: 0.97 → pass

### 2026-11-04 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-02 (score 77, +15)

- [security improvement] Injection markers: unverified → pass
- [security improvement] TLS certificate: unverified → pass
- [security improvement] HSTS header: unverified → pass
- [security improvement] Transport: fail → pass
- [security] Authorization: Authorisation not fully verified: no authorisation is required to call this server, and 6 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
- [functional regression] MCP protocol: unverified → fail
- [functional improvement] Endpoint reachability: unreachable → reachable
- [functional improvement] Tool coverage: unverified → 100
- [functional improvement] Stability: unverified → 0.90

### 2026-11-01 (score 62, −16)

The score moved with no change recorded against any check. We would rather say so than guess.

### 2026-10-30 (score 78, 0)

- [security regression] Endpoint reachability: reachable → unreachable
- [security regression] Stability: pass → unverified
- [security regression] Tool safety: pass → unverified
- [security regression] TLS certificate: pass → unverified
- [security regression] HSTS header: pass → unverified
- [security regression] Transport: pass → fail
- [security] Authorization: Authorisation not yet verified: we couldn't confirm whether this endpoint requires it.
- [functional regression] Capabilities: fail → unverified
- [functional regression] Tool coverage: 100 → unverified

### 2026-10-29 (score 78, 0)

- [security improvement] Injection markers: unverified → pass
- [security improvement] Stability: unverified → pass
- [security improvement] TLS certificate: unverified → pass
- [security improvement] HSTS header: unverified → pass
- [security improvement] Transport: fail → pass
- [security] Authorization: Authorisation not fully verified: no authorisation is required to call this server, and 6 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
- [functional regression] MCP protocol: unverified → fail
- [functional improvement] Endpoint reachability: unreachable → reachable
- [functional improvement] Tool coverage: unverified → 100

### 2026-10-28 (score 78, 0)

- [security regression] Endpoint reachability: reachable → unreachable
- [security regression] Tool safety: pass → unverified
- [security regression] TLS certificate: pass → unverified
- [security regression] Stability: 0.97 → unverified
- [security regression] HSTS header: pass → unverified
- [security regression] Transport: pass → fail
- [security] Authorization: Authorisation not yet verified: we couldn't confirm whether this endpoint requires it.
- [functional regression] Capabilities: fail → unverified
- [functional regression] Tool coverage: 100 → unverified

### 2026-10-27 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (6)

### `render_diagram` (~120 tokens)

Render PlantUML source text to a diagram image. Returns a PNG image block (format "png") or the SVG markup as text (format "svg", default), plus the shareable render URL. The source is validated first: on a syntax error the result is an error object with line, column, hint and a help link so you can fix the diagram and retry.

Input parameters:

- `format` (string)
- `text` (string, required): PlantUML source including @startuml ... @enduml (or the matching @start/@end pair)

### `validate_diagram` (~75 tokens)

Check PlantUML source without rendering. Returns {ok:true, diagram_type} or {ok:false, error:{code, message, line, column, source_line, hint, diagram_type_detected, help}}. Cheap - call it in a generate -> validate -> fix loop before rendering.

Input parameters:

- `text` (string, required)

### `encode_source` (~142 tokens)

Encode PlantUML source into a URL token and ready-to-use share/render URLs (svg + png). The result carries url_ok: GET URLs only work while the token is at most 16000 characters; when url_ok is false do not share the URLs - render with render_diagram instead (it uses the POST API, no size limit up to 5 MB). Tokens use PlantUML's own 64-character alphabet ("0-9 A-Z a-z - _") over raw DEFLATE. This is NOT base64 - never encode or decode tokens with a base64 codec; use encode_source / decode_token.

Input parameters:

- `text` (string, required)

### `decode_token` (~96 tokens)

Recover the PlantUML source from a token or from any PlantUML render URL (the token is extracted automatically). Tokens use PlantUML's own 64-character alphabet ("0-9 A-Z a-z - _") over raw DEFLATE. This is NOT base64 - never encode or decode tokens with a base64 codec; use encode_source / decode_token.

Input parameters:

- `encoded` (string, required): Token or full render URL

### `list_diagram_types` (~42 tokens)

List the 22 supported diagram/reference types with a one-line description and the local syntax reference URL for each. Use it to pick the right @start directive.

### `get_syntax_reference` (~72 tokens)

Get the syntax reference entry for one diagram type: description, a render-verified example, and the help page URL. Use it to ground diagram generation.

Input parameters:

- `type` (string, required): Type id or label, e.g. "sequence", "class", "mindmap", "gantt", "json"

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-singsk-uml-plantuml/uml#diagnostics

## Score history

- 2026-11-05: 78
- 2026-11-04: 78
- 2026-11-03: 77
- 2026-11-02: 77
- 2026-11-01: 62
- 2026-10-31: 78
- 2026-10-30: 78
- 2026-10-29: 78
- 2026-10-28: 78
- 2026-10-27: 78
- 2026-10-26: 77
- 2026-10-25: 78
- 2026-10-24: 78
- 2026-10-23: 78
- 2026-10-22: 78
- 2026-10-21: 78
- 2026-10-20: 77
- 2026-10-19: 77
- 2026-10-18: 77
- 2026-10-17: 78
- 2026-10-16: 78
- 2026-10-15: 78
- 2026-10-14: 78
- 2026-10-13: 78
- 2026-10-12: 16
- 2026-10-10: 31
- 2026-10-04: 47
- 2026-10-03: 62
- 2026-10-02: 78
- 2026-10-01: 78

## Common questions

### What is the uml.singsk.com PlantUML MCP server?

uml.singsk.com PlantUML is an MCP server listed in the public MCP registry as com.singsk/uml-plantuml. Render, validate, encode/decode PlantUML diagram-as-code; 22 diagram types. Free, no auth. This page covers its hosted endpoint (https://uml.singsk.com/mcp).

### Is the uml.singsk.com PlantUML MCP server safe to use?

uml.singsk.com PlantUML scores 78 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the uml.singsk.com PlantUML MCP server expose?

uml.singsk.com PlantUML exposes 6 tools: render_diagram, validate_diagram, encode_source, decode_token, list_diagram_types, get_syntax_reference. Their descriptions and schemas cost roughly 547 tokens of context every time the server is loaded.

### Does the uml.singsk.com PlantUML MCP server require authentication?

No. We connected to uml.singsk.com PlantUML without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the uml.singsk.com PlantUML MCP server still maintained?

uml.singsk.com PlantUML is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What did VerifyMCP test on the uml.singsk.com PlantUML MCP server?

VerifyMCP ran 12 checks on uml.singsk.com PlantUML, covering TLS certificate, HTTPS, HSTS header, DNSSEC and 8 more. One item could not be completed, a gap on our side rather than a finding about uml.singsk.com PlantUML: Authorization. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.

## Links

- Remote endpoint: https://uml.singsk.com/mcp
- Website: https://uml.singsk.com/
- Changelog RSS feed: https://verifymcp.io/servers/com-singsk-uml-plantuml/uml.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-singsk-uml-plantuml/uml/changelog.json
- Trust report (JSON): https://verifymcp.io/servers/com-singsk-uml-plantuml/uml.json
- HTML version of this page: https://verifymcp.io/servers/com-singsk-uml-plantuml/uml