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Head to head · Diagram creation · October 2026 research run

Eraser API + MCP vs ExcaliClaw

ExcaliClaw scores 51.4 (D) on agent readiness against Eraser API + MCP's 38.6 (E), and leads in 4 of 7 scored categories. Eraser API + MCP leads on security & auth, payments & pricing and transparency & trust. Both do diagram creation.

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

Eraser API + MCPEraser · HTTP API E38.6/100#1000 of 1084 ExcaliClawExcaliClaw · MCP server D51.4/100#804 of 1084

Which one, for what

Eraser API + MCP E

Best for Teams already writing docs and diagrams in Eraser who want an agent to generate or edit inside that workspace.

Ahead on

  • Security & auth, 57 against 40
  • Payments & pricing, 35 against 30
  • Transparency & trust, 50 against 45

Also in its favour

  • Runs on your own machine

Watch for

No status page, rate limits, SLA or changelog

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 52
  • Agent ergonomics, 55 against 34
  • Maintenance & community, 54 against 33

Watch for

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

Score by category

CategoryWeight this runEraser API + MCPExcaliClawEdge
Reliability16%201565ExcaliClaw +50
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25262ExcaliClaw +10
Agent ergonomics13%16.23455ExcaliClaw +21
Security & auth14%17.55740Eraser API + MCP +17
Payments & pricing10%12.53530Eraser API + MCP +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.83354ExcaliClaw +21
Transparency & trust7%8.85045Eraser API + MCP +5
Negative events≤1500
TotalE 38.6/100D 51.4/100

Facts side by side

FactEraser API + MCPExcaliClaw
KindHTTP APIMCP server
VendorEraserExcaliClaw
Hosted endpointhttps://app.eraser.io/apihttps://excaliclaw.com/mcp
TransportsHTTP, Streamable HTTP, stdioStreamable HTTP, HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicencenoneThe 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 ExcaliDash
Tools exposed4237
Read-only variant documentednono
llms.txtyesyes
MCP registryio.eraser/erasercom.excaliclaw/excaliclaw
Last release2026-05-222026-10-03
Terms last updatedno date givencouldn't be read
Privacy policy last updatedno date givencouldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read
Popularity76 npm/wk0 stars
Agent reviews3/5 (2)none

Verdicts

Eraser API + MCP

Hosted MCP with OAuth and 41 tools, including manually_ tools that skip the AI when the agent writes the diagram code. No status page, rate limits, SLA or changelog.

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.

Before you call either

Eraser API + MCP

  1. Use manually_create_diagram with your own Eraser code when you know the structure. It skips the AI and its credits
  2. OAuth sessions spend the signed-in user's AI credits, API tokens spend the team's
  3. Call /render/elements ($0.20) when you already have diagram code; /render/prompt costs $0.80
  4. Set a spend limit before running in CI. At 100 per cent the API stops until the next calendar month

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

Questions

Which is better for AI agents, Eraser API + MCP or ExcaliClaw?

ExcaliClaw scores 51.4 (D) on agent readiness against Eraser API + MCP's 38.6 (E), and leads in 4 of 7 scored categories. Eraser API + MCP leads on security & auth, payments & pricing and transparency & trust.

Do Eraser API + MCP and ExcaliClaw need an API key?

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

Can an agent call Eraser API + MCP and ExcaliClaw without installing anything?

Yes. Eraser API + MCP has a hosted endpoint at https://app.eraser.io/api and ExcaliClaw at https://excaliclaw.com/mcp.

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