C4Loom
Server Configuration
Describes the environment variables required to run the server.
| Name | Required | Description | Default |
|---|---|---|---|
| C4_JAVA | No | Optional Java executable override. | java |
| C4_IDLE_MS | No | Engine inactivity window, not total execution time. | 120000 |
| C4_CHROMIUM | No | Playwright-managed Chromium; optional executable override. | |
| C4_CONNECT_MS | No | Official MCP connection/request wait, renewed by tool progress. | 20000 |
| C4_OUTPUT_ROOT | No | The allowed root for generated runs and artifact reads. | <checkout>/output |
| C4_RUNTIME_DIR | No | Directory for pinned engines and engines.json. | <checkout>/.runtime |
| C4_NODE_MODULES | No | Optional externally managed Node package directory. | |
| C4_DOWNLOAD_IDLE_MS | No | Download inactivity window. | 120000 |
| C4_OFFICIAL_MCP_URL | No | Unset; optional official MCP endpoint. | |
| C4_ALLOW_REMOTE_OFFICIAL | No | Unset; set to 1 to permit a non-loopback validator. |
Instructions
Guidance the server publishes about itself, which clients place ahead of the tool catalog so the model reads it before choosing anything.
This server publishes no instructions, or was last inspected before Glama recorded them.
Capabilities
Features and capabilities supported by this server
Protocol revision2025-11-25
| Capability | Details |
|---|---|
| tools | {
"listChanged": true
} |
Tools
Functions exposed to the LLM to take actions
| Name | Description |
|---|---|
| generate_c4B | Generate Structurizr DSL/JSON and real C1 context, C2 container, C3 component and C4 code diagrams from an explicit architecture model. Returns transparent SVG/PNG, a viewer and a hashed manifest. |
| render_structurizrA | Render real C1-C3 images from self-contained DSL. Use generate_c4 with codeViews for C4. Rejects executable directives and external references. |
| read_artifactB | Return PNG images, editable sources or manifests, restricted to the output root. |
| check_runtimeA | Verify Structurizr and PlantUML hashes. This check does not replace a real generation. |
Prompts
Interactive templates invoked by user choice
| Name | Description |
|---|---|
No prompts | |
Resources
Contextual data attached and managed by the client
| Name | Description |
|---|---|
No resources | |
TDQS
Scored across 4 tools
generate_c4 and render_structurizr both produce C1-C4 diagrams, which is the one real overlap, but the descriptions explicitly delineate them (explicit architecture model vs. self-contained DSL, and render_structurizr points to generate_c4 with codeViews for C4). read_artifact and check_runtime are clearly distinct utility operations.
All four tools follow a consistent verb_noun snake_case pattern (generate_c4, render_structurizr, read_artifact, check_runtime). No mixing of conventions or vague standalone verbs.
Four tools is a tight, well-scoped surface for a diagram generation server, with generation, rendering, artifact retrieval, and runtime verification each earning a slot. It is on the lean side but nothing feels redundant.
The core loop (generate, render, read output, verify runtime) is covered, but read_artifact requires knowing an exact path and there is no list/gallery tool to discover existing artifacts, nor any cleanup or model-validation operation. Agents hitting an unknown output filename have a dead end.