# Line9 (remote · mcp.line9.ai)

Render Mermaid with Line9 layout in your assistant.

- Trust score: 75/100 (medium)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-25

## Components

- remote · `mcp.line9.ai`: 75/100 (this document), [markdown](https://verifymcp.io/servers/ai-line9-diagrams/mcp.md), [page](https://verifymcp.io/servers/ai-line9-diagrams/mcp)

## Channel facts

- Endpoint: `https://mcp.line9.ai/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.4.4`

## 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 2026-09-25.

- **Endpoint Security**: 74/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - 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**: 77/100
  - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 636 tokens (~159/item across 4 items; 3 tools + 1 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).
  - Supports UI / widget rendering.

## Install

### How do I install the Line9 MCP server?

Line9 is a hosted endpoint at https://mcp.line9.ai/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 ai-line9-diagrams 'https://mcp.line9.ai/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "ai-line9-diagrams": {
      "url": "https://mcp.line9.ai/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "ai-line9-diagrams": {
      "type": "http",
      "url": "https://mcp.line9.ai/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.ai-line9-diagrams]
url = "https://mcp.line9.ai/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "ai-line9-diagrams": {
      "type": "remote",
      "url": "https://mcp.line9.ai/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add ai-line9-diagrams --url 'https://mcp.line9.ai/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  ai-line9-diagrams:
    url: "https://mcp.line9.ai/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "ai-line9-diagrams": {
      "Transport": "http",
      "Url": "https://mcp.line9.ai/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add ai-line9-diagrams -t streamable-http -u 'https://mcp.line9.ai/mcp'
```

### Other

```json
{
  "mcpServers": {
    "ai-line9-diagrams": {
      "type": "http",
      "url": "https://mcp.line9.ai/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.

### 2026-09-25 (score 75, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-24 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-22 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-20 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-18 (score 72, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-09-17 (score 71)

First indexed and scored.

## MCP tools (3)

### `render_diagram` (~408 tokens)

Render diagram

Render Mermaid source with Line9's layout engine. Call this whenever you write or change Mermaid and the user should see the result. Flowcharts and sequence diagrams get Line9's layout; other Mermaid kinds are rendered with Mermaid's own layout and flagged as such. Returns a short verdict — kind, size, warnings, or a parse error with its line and column — plus an "Open in Line9" link. On a parse error, fix the named line and call again. Assistants that support MCP Apps show the diagram in a panel; there, do not paste the SVG or repeat the source in your reply. In an assistant with no panel (a terminal or editor), reply with the verdict line and the `open_url` link — that link is the only way the user sees the diagram. Write flowcharts as `flowchart LR` unless the user asks for top-to-bottom; chat panels are wide and short. No sign-in needed; renders carry a small Line9 mark unless the user is signed in to Line9 Pro. Set theme, orientation, spacing and legend in the source itself (`line9:` frontmatter; `flowchart LR`), never as arguments. This connector cannot publish or save. To publish, the user opens the diagram in Line9 (the `open_url` link) and publishes there — not with the Line9 CLI.

Input parameters:

- `plan` (string): Opaque plan from a previous result (widget use). A hint only: skips the solve when it still fits the source.
- `source` (string, required): Mermaid source. Optional YAML frontmatter is honoured — set it in the source, never as arguments: `title`, and a nested `line9:` block with `theme` (one of `boardroom`, `linen`, `blueprint`), `scale:…

Output parameters:

- `config` (object)
- `controls` (object)
- `diagram` (object)
- `diagram_type` (string|null)
- `diagrams` (array)
- `edge_count` (number)
- `engine_version` (string)
- `error` (object)
- `fallback_reason` (string)
- `height` (number)
- `mermaid_version` (string)
- `node_count` (number)
- `open_url` (string)
- `orientation` (string)
- `path` (string)
- `plan` (string)
- `render_mode` (string)
- `schema_version` (number)
- `signed_in` (boolean)
- `source` (string)
- `status` (string)
- `stop_reason` (string)
- `svg` (string)
- `truncated` (boolean)
- `warnings` (array)
- `watermark` (boolean)
- `width` (number)

### `list_diagrams` (~84 tokens)

List my diagrams

List the diagrams published in the user's Line9 workspace(s): name, visibility, version, last update and permalink. Use it to find a diagram before `get_diagram`. Requires Line9 sign-in.

Input parameters:

- `limit` (integer): Maximum rows to return (1–100; default 50).
- `query` (string): Case-insensitive substring of the diagram name.

Output parameters:

- `config` (object)
- `controls` (object)
- `diagram` (object)
- `diagram_type` (string|null)
- `diagrams` (array)
- `edge_count` (number)
- `engine_version` (string)
- `error` (object)
- `fallback_reason` (string)
- `height` (number)
- `mermaid_version` (string)
- `node_count` (number)
- `open_url` (string)
- `orientation` (string)
- `path` (string)
- `plan` (string)
- `render_mode` (string)
- `schema_version` (number)
- `signed_in` (boolean)
- `source` (string)
- `status` (string)
- `stop_reason` (string)
- `svg` (string)
- `truncated` (boolean)
- `warnings` (array)
- `watermark` (boolean)
- `width` (number)

### `get_diagram` (~132 tokens)

Get a diagram

Fetch a published diagram's current Mermaid source by name or slug, and show it rendered. The returned source is stamped with the diagram's identity — keep the `line9:` frontmatter block when you edit it so that Line9 recognises the diagram when it is opened and published there instead of creating a new one. Requires Line9 sign-in. This connector cannot publish or save. To publish, the user opens the diagram in Line9 (the `open_url` link) and publishes there — not with the Line9 CLI.

Input parameters:

- `diagram` (string, required): Diagram name, slug, or trailing public_ref.

Output parameters:

- `config` (object)
- `controls` (object)
- `diagram` (object)
- `diagram_type` (string|null)
- `diagrams` (array)
- `edge_count` (number)
- `engine_version` (string)
- `error` (object)
- `fallback_reason` (string)
- `height` (number)
- `mermaid_version` (string)
- `node_count` (number)
- `open_url` (string)
- `orientation` (string)
- `path` (string)
- `plan` (string)
- `render_mode` (string)
- `schema_version` (number)
- `signed_in` (boolean)
- `source` (string)
- `status` (string)
- `stop_reason` (string)
- `svg` (string)
- `truncated` (boolean)
- `warnings` (array)
- `watermark` (boolean)
- `width` (number)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/ai-line9-diagrams/mcp#diagnostics

## Score history

- 2026-09-25: 75
- 2026-09-24: 75
- 2026-09-23: 74
- 2026-09-22: 74
- 2026-09-21: 73
- 2026-09-20: 73
- 2026-09-19: 72
- 2026-09-18: 72
- 2026-09-17: 71

## Common questions

### What is the Line9 MCP server?

Line9 is an MCP server listed in the public MCP registry as ai.line9/diagrams. Render Mermaid with Line9 layout in your assistant. This page covers its hosted endpoint (https://mcp.line9.ai/mcp).

### Is the Line9 MCP server safe to use?

Line9 scores 75 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 Line9 MCP server expose?

Line9 exposes 3 tools: render_diagram, list_diagrams, get_diagram. Their descriptions and schemas cost roughly 624 tokens of context every time the server is loaded.

### Does the Line9 MCP server require authentication?

No. We connected to Line9 without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Line9 MCP server still maintained?

Line9 is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://mcp.line9.ai/mcp
- Website: https://line9.ai/mcp
- Changelog RSS feed: https://verifymcp.io/servers/ai-line9-diagrams/mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/ai-line9-diagrams/mcp.json
- HTML version of this page: https://verifymcp.io/servers/ai-line9-diagrams/mcp