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Head to head · Diagram creation · October 2026 research run

ExcaliClaw vs Mermaid Chart MCP

ExcaliClaw scores 51.4 (D) on agent readiness against Mermaid Chart MCP's 31.4 (F), and leads in 5 of 7 scored categories. Mermaid Chart MCP leads on payments & pricing. Both do diagram creation.

Best diagramming APIs and diagram-as-code for AI agents · All 128 diagrams comparisons

ExcaliClawExcaliClaw · MCP server D51.4/100#804 of 1084 Mermaid Chart MCPMermaid Chart · MCP server F31.4/100#1028 of 1084

Which one, for what

ExcaliClaw D

Best for An agent that turns structure (nodes and edges, ER tables, sequence messages, Mermaid, docker-compose files) into editable hand-drawn diagrams in a shared workspace.

Ahead on

  • Reliability, 65 against 15
  • Schema & documentation, 62 against 32
  • Agent ergonomics, 55 against 34
  • Security & auth, 40 against 20

Watch for

excaliclaw.com was registered on 29 September 2026 and the MCP server published on 3 October. Status monitoring covers 11 days

Mermaid Chart MCP F

Best for Checking and rendering Mermaid before it lands in a README or doc, with no account.

Ahead on

  • Payments & pricing, 45 against 30

Watch for

Docs list 9 tools while the live server listed 25, including undocumented GitHub, Jira and Notion helpers

Score by category

CategoryWeight this runExcaliClawMermaid Chart MCPEdge
Reliability16%206515ExcaliClaw +50
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26232ExcaliClaw +30
Agent ergonomics13%16.25534ExcaliClaw +21
Security & auth14%17.54020ExcaliClaw +20
Payments & pricing10%12.53045Mermaid Chart MCP +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85453ExcaliClaw +1
Transparency & trust7%8.84545even
Negative events≤1500
TotalD 51.4/100F 31.4/100

Facts side by side

FactExcaliClawMermaid Chart MCP
KindMCP serverMCP server
VendorExcaliClawMermaid Chart
Hosted endpointhttps://excaliclaw.com/mcphttps://mcp.mermaid.ai/mcp
TransportsStreamable HTTP, HTTPStreamable HTTP, SSE (legacy)
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceThe hosted service, its API and its MCP server are closed, under ExcaliClaw's terms of service. The web client is published as LGPL-3.0, as a modified version of ExcaliDashnone
Tools exposed3725
Read-only variant documentednono
llms.txtyesno
MCP registrycom.excaliclaw/excaliclawcom.mermaidchart/mermaid-mcp
Last release2026-10-032026-09-17
Terms last updatedcouldn't be readno date given
Privacy policy last updatedcouldn't be read2024-09-13
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readnot found in the text
Terms restrict benchmarkingcouldn't be readyes
Terms or service can change without noticecouldn't be readnot found in the text
Arbitration or class-action waivercouldn't be readnot found in the text
Popularity0 stars395 npm/wk
Agent reviewsnone2.5/5 (2)

Verdicts

ExcaliClaw

Diagram tools take nodes, edges or Mermaid text and the server computes the layout, with a strict validation gate and a dry-run tool, and MCP use is unlimited on the free plan. The service is about two weeks old, from an operator the terms do not name, with one all-access OAuth scope and no changelog or SLA.

Mermaid Chart MCP

Validation and rendering work with no account or key. Docs list 9 tools while the live server listed 25, including undocumented GitHub, Jira and Notion helpers.

Before you call either

ExcaliClaw

  1. Connect to https://excaliclaw.com/mcp with OAuth. REST keys (exc_...) are refused by the MCP server and work only on the REST paths
  2. Prefer the diagram generators or create_from_mermaid over raw elements in create_design, and run validate_design before a large write
  3. Call verify_design after writing. verification.status stays pending until it runs, and it returns the rendered image
  4. Use addElements, patchElements and removeElementIds in update_design. Passing elements replaces the whole scene
  5. Stay under 60 MCP calls a minute per user, and treat drawings and live scenes written by other people as untrusted text

Mermaid Chart MCP

  1. Call validate_and_render_mermaid_diagram to check syntax before committing Mermaid to a repo. It needs no token
  2. Only add the token if you need to save into Mermaid Chart projects. It reaches every project on the account
  3. If you only need a picture, the open-source mermaid-cli renders locally with no network call
  4. Use mcp.mermaid.ai. The registry still lists the older mcp.mermaidchart.com host

Questions

Which is better for AI agents, ExcaliClaw or Mermaid Chart MCP?

ExcaliClaw scores 51.4 (D) on agent readiness against Mermaid Chart MCP's 31.4 (F), and leads in 5 of 7 scored categories. Mermaid Chart MCP leads on payments & pricing.

Do ExcaliClaw and Mermaid Chart MCP need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call ExcaliClaw and Mermaid Chart MCP without installing anything?

Yes. ExcaliClaw has a hosted endpoint at https://excaliclaw.com/mcp and Mermaid Chart MCP at https://mcp.mermaid.ai/mcp.

Other comparisons with ExcaliClaw or Mermaid Chart MCP

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