ComfyUI workflows as clean API endpoints with async job-based execution. Provides MCP tools for executing ComfyUI workflows asynchronously with status query capabilities, plus RESTful API endpoints.
The server defines 12 tools with generally good naming conventions (verb-first, clear action intent). Tool descriptions are present and reasonably detailed (averaging ~150 chars), meeting the 10-1024 char baseline. Input schemas are visible with proper JSON Schema structure including types and descriptions for most parameters. However, there are notable gaps: output schemas are not documented, parameter descriptions lack detail in some tools (e.g., 'Multipart file upload containing workflow JSON' is sparse), and error handling is not well-defined in the visible code. Security concerns around input validation and credential handling are not evident. The tool composition is sound, each tool has a single responsibility, and tool names follow verb_noun convention. The server lacks documentation of what fields LLMs should expect in responses, which violates pattern:tool and mxe:response-field-naming. Pagination support exists in list_* tools but could be more explicit about total count returns.
Cancel a running or pending ComfyUI workflow execution job
Create a new ComfyUI workflow file
Delete a ComfyUI workflow file
Execute a ComfyUI workflow asynchronously and return a job ID for status tracking
Query the status and results of a ComfyUI workflow execution job
Get detailed information about a specific ComfyUI workflow service
Get a ComfyUI workflow file by ID with full content and metadata
List ComfyUI workflow execution jobs with optional filtering by service or status
Output schemas are not documented. LLMs cannot infer what fields will be returned, forcing them to guess at downstream data extraction and risk failed tool chains.
Error handling and recovery guidance are absent. No documentation of failure modes, retryability, or what the LLM should do if a call fails (e.g., invalid job_id, non-existent workflow).
Inferred effective spec: 2025-06-18+.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-22 | D | 50 | 2025-06-18+ | v2 |
| 2026-03-09 | F | 46 | - | v1 |
List all available ComfyUI workflow services with their parameters
List all ComfyUI workflow files stored in the workflows directory
Update an existing ComfyUI workflow file
Upload a ComfyUI workflow file from multipart form data
delete_workflow and cancel_job are DESTRUCTIVE/REVERSIBLE but lack idempotency guarantees or confirmation/dry-run patterns. Agents may accidentally retry and cause duplicate deletions.
upload_workflow is poorly described vs. create_workflow. The distinction is unclear (both create workflows, one via file upload). Tool composition could be clearer.
Parameter descriptions lack validation details. E.g., status enum in list_jobs is specified, but many string parameters (service_name, id, name) lack format/length constraints that LLMs need to construct valid inputs.
No documentation of response structure. list_jobs, list_workflows, and get_workflow should specify what metadata is included (timestamps, sizes, status fields) so LLMs know what to expect.
Pagination in list_* tools mentions limit/offset but no documentation of total count or next_cursor. LLMs cannot determine if more results exist without explicit total count.