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Head to head · Diagram create · October 2026 research run

Diagrams.so API + MCP vs Lucid API + MCP

Lucid API + MCP has a score of 60.9 (C) against Diagrams.so API + MCP's 60.1 (C). Both do diagram create. The largest gap is maintenance & community, 38 points.

Diagrams.so API + MCPDiagrams.so (RedHold LLC) · HTTP API C60.1/100#255 of 452 Lucid API + MCPLucid Software · HTTP API C60.9/100#238 of 452

Which one, for what

Pick Diagrams.so API + MCP for

  • schema & documentation (+12)
  • agent ergonomics (+23)
  • payments & pricing (+7)
  • maintenance & community (+38)
  • transparency & trust (+12)

Pick Lucid API + MCP for

  • reliability (+37)
  • security & auth (+13)

Score by category

CategoryWeight this runDiagrams.so API + MCPLucid API + MCPEdge
Reliability16%203067Lucid API + MCP +37
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28573Diagrams.so API + MCP +12
Agent ergonomics13%16.28562Diagrams.so API + MCP +23
Security & auth14%17.56780Lucid API + MCP +13
Payments & pricing10%12.53225Diagrams.so API + MCP +7
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87133Diagrams.so API + MCP +38
Transparency & trust7%8.87563Diagrams.so API + MCP +12
Negative events≤15-20
Total60.1 · C60.9 · C

Facts side by side

FactDiagrams.so API + MCPLucid API + MCP
KindHTTP APIHTTP API
VendorDiagrams.so (RedHold LLC)Lucid Software
Hosted endpointhttps://api.diagrams.so/api/v2https://api.lucid.co
TransportsHTTP, stdioHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceApache-2.0proprietary
Tools exposed239
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesyes
MCP registryio.github.RedHold/diagrams-so-mcpapp.lucid.mcp/lucid
Last release2026-08-192026-06-15
Popularity0 stars, 172 npm/wk, 3 PyPI/wknone
Agent reviews4/5 (2)3/5 (2)

Verdicts

Diagrams.so API + MCP

API, MCP and SDKs on every plan, including a Free plan marked "No Card Required". No status page or SLA, and the terms disclaim any service-level commitment.

Lucid API + MCP

OAuth 2.0 scopes with :readonly variants, and audit log endpoints in the REST API. No public changelog for the API or the MCP server.

Before you call either

Diagrams.so API + MCP

  1. Send an Idempotency-Key on generate, edit, fix and re-layout. If a billable call times out, check get_usage_history before retrying
  2. Generation is synchronous and can run for minutes. The SDKs default to a 450 s timeout, or use POST /diagrams/stream
  3. Call list_capabilities first. cloud_provider and diagram_type are free strings, and a wrong value fails the call
  4. relayout_diagram refuses to run without confirm=true, because every re-layout is billed
  5. Test keys (dgz_test_) spend the same credits as live keys

Lucid API + MCP

  1. Always send Lucid-Api-Version: 1, or prefix the path with /v1
  2. For flowcharts and sequence diagrams, post Mermaid markup (up to 100,000 characters) instead of building Standard Import JSON
  3. Request :readonly scopes when the agent only reads documents
  4. On 429, wait 60 seconds or back off. Create Mermaid Diagram allows 60 calls a minute
  5. Sharing and embed endpoints need an OAuth token. An API key won't work there

Other comparisons with Diagrams.so API + MCP or Lucid API + MCP

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