Head to head · Diagram creation · October 2026 research run

AI Diagram Maker MCP vs Cloudviz API

AI Diagram Maker MCP scores 43.8 (E) on agent readiness against Cloudviz API's 38 (E), and leads in 4 of 7 scored categories. Cloudviz API leads on security & auth and transparency & trust. Both do diagram creation.

Best diagramming APIs and diagram-as-code for AI agents · All 147 diagrams comparisons

Which one, for what

AI Diagram Maker MCP E

Best for Quick architecture, sequence, ERD and flowchart diagrams from a coding agent, with a link to edit them.

Ahead on

  • Reliability, 30 against 20
  • Schema & documentation, 75 against 58
  • Agent ergonomics, 66 against 50
  • Maintenance & community, 17 against 5

Also in its favour

  • Runs on your own machine

Watch for

Last release 3.0.8 on 10 April 2026, and the registry entry still says 1.0.0

Cloudviz API E

Best for Documenting what already runs in AWS, for example regenerating a diagram after each deploy and posting it to Confluence or Slack.

Ahead on

  • Security & auth, 53 against 45
  • Transparency & trust, 48 against 35

Watch for

AWS only, and API access starts at the $49 a month Team plan

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Schema & documentation AI Diagram Maker MCP +17

AI Diagram Maker MCP 75

All five tools have zod input schemas in src/tools, and the repository ships an OpenAPI 3 file for POST /api/v2/diagrams/generate (25). No llms.txt (404) and no docs site for agents beyond the README (0). Each description says what the tool does and when to use it, listing trigger phrases and the diagram types, without saying when another tool fits better (16 of 20). content has a minimum length and diagramType an eight-value enum; the OpenAPI adds inputType and format enums (13 of 15). Examples in the parameter descriptions and README, and the OpenAPI documents 400, 401, 402, 422 (D2 failed to compile) and 429 with typed error bodies (13 of 15). Git tags from v1.1.1 to v3.0.8 and a /api/v2 path, with no changelog or release notes (8 of 15). 25 + 0 + 16 + 13 + 13 + 8 = 75.

Cloudviz API 58

Public OpenAPI 3.0.3 file with 7 operations (25). No llms.txt, the URL returns 404 (0). Every operation has a description of what it does, none say when not to use it (10). The snapshot format parameter is an enum of svg, png, pdf, drawio, jsonDiagram and jsonSnapshot, and the path is typed (10). Response codes 200, 201, 202, 204, 400, 401, 403 and 404 are documented, plus a Postman collection, but few example bodies (10). info.version is 1.0.0 and there's no changelog (3).

Agent ergonomics AI Diagram Maker MCP +16

AI Diagram Maker MCP 66

Five compact tools (25). Output can be SVG or PNG and the API can return the D2 source with debug, but there's nothing to page or trim, and results carry the rendered image (10 of 20). Typed error bodies with codes, a 422 that returns the failing D2 code, and retryAfter on 429 (16 of 20). No readOnlyHint or other annotations in the source and no idempotency key, and every call spends credits (5 of 20). Only content is required and the hosted endpoint needs no install, but there is no SDK beyond the server (10 of 15). 25 + 10 + 16 + 5 + 10 = 66.

Cloudviz API 50

Seven endpoints, so the contract is small, and output can be narrowed with generation profiles and the two JSON formats (15). Filtering through saved views and profiles, no pagination on the account list (10). Error codes are documented, messages are not (10). The snapshot GET can be repeated safely while it returns 202, writes to AWS accounts have no idempotency keys (10). Few required parameters, but no official SDK in any language (5).

Transparency & trust Cloudviz API +13

AI Diagram Maker MCP 35

The MCP server is MIT (package.json and LICENSE, added 18 March 2026). The service is closed, under terms last updated 24 September 2025 that name the operator only as AI Diagram Maker (20 of 30). The privacy policy of the same date keeps diagrams, revisions and chat prompts and responses 'as long as necessary', and the terms license user input 'to provide and improve our services', with no retention periods and no word on model training or the AI providers used (8 of 30). No deprecation policy or dated notices (0). No subprocessors or data locations named (0). The MCP server's source sends no telemetry of its own. 20 + 8 + 0 + 0 = 28.

Cloudviz API 48

Closed source with terms under Latvian law, last updated 26 March 2019 (15). The privacy policy is hosted on iubenda, which our reader couldn't load (robots.txt). The security page covers encryption and hosting but no retention period or DPA (10). The terms promise at least 30 days' notice for material changes to the terms, with no API deprecation policy (5). AWS hosting and Stripe for payments are named, no region (8).

Maintenance & community AI Diagram Maker MCP +12

AI Diagram Maker MCP 17

Last release v3.0.8, published to npm on 10 April 2026, 210 days before this check (0). No release since 8 August (0). Four issues in all. The two open ones, from 4 May (hosted MCP credit usage) and 13 October 2026, show no reply, and one closed issue had a comment (5 of 25). In the official MCP registry under the GitHub-verified namespace io.github.erajasekar, but the entry is 1.0.0 from 19 March 2026 while npm is on 3.0.8 (10 of 15). The only workflow publishes to the registry. No tests or CI, and the MCP SDK floor is ^1.9.0 (2 of 10). 0 + 0 + 5 + 10 + 2 = 17.

Cloudviz API 5

No changelog, release notes or dated API change found, so we can't date the last release (0). No dated entries in the last 90 days (0). The newest blog post is from 14 March 2025, and the GitHub samples repo was last touched on 30 October 2023. Support by email, with priority support on Team, not tested (5). No official SDK (0). No package to assess (0).

Reliability AI Diagram Maker MCP +10

AI Diagram Maker MCP 30

Hosted lines, because every tool call is generated on the AI Diagram Maker service, through the hosted endpoint or the npx server. No status page found on the site or in the README (0). No readable incident history (5). The only rate-limit number is the example in the OpenAPI 429 schema ('Maximum 100 requests per day exceeded.'), which isn't stated as the limit (5 of 15). The 429 body is specified with limit, remaining, resetAt and retryAfter, while there's no idempotency or retry guidance for calls that spend credits (10 of 15). No SLA found (0). Nothing labels the service or server beta (10). 0 + 5 + 5 + 10 + 0 + 10 = 30.

Cloudviz API 20

No status page found, and status.cloudviz.io doesn't resolve (0). No readable incident history (5). The OpenAPI description says requests are throttled per key on rate, burst and a daily cap, with no numbers (0). 429 is named but there's no Retry-After or backoff guidance, though the spec does explain the 202 in-progress reply and polling the same URL (5). No SLA on any plan, and the pricing page never mentions one (0). The API is sold as a working product, not a beta (10).

Security & auth Cloudviz API +8

AI Diagram Maker MCP 45

Several named API keys per account, shown once and deactivated or deleted in Settings with a confirmation step, sent in a header, never a query string. No scopes, and the user guide says anyone with a key can access the account (20 of 30). The tools only create diagrams and can't change or delete anything in the account, but there's no read-only key (12 of 20). Tools return diagrams built from the caller's own input. Image inputs can be any public URL (10 of 15). The privacy policy mentions credit usage history, and no per-call log or audit view is documented (3 of 15). No security.txt, disclosure policy, bug bounty or certification found (0). 20 + 12 + 10 + 3 + 0 = 45.

Cloudviz API 53

API key in the x-api-key header, each key read-only or read and write and changeable at any time per the 30 September check. No secret in URLs (25). AWS access is a cross-account role with a per-customer external ID, and Cloudviz recommends the AWS ReadOnlyAccess policy or a narrower custom one. No confirmation step before the DELETE on an AWS account (15). Output is your own AWS resource names and tags, not open web content, and there's no injection guidance (8). No audit log for API calls found (0). A security page with security@cloudviz.io, AES-256 at rest and TLS in transit. The certifications it lists are AWS's, not Cloudviz's. No security.txt (404), no bug bounty (5).

Score by category

CategoryWeight this runAI Diagram Maker MCPCloudviz APIEdge
Reliability16%203020AI Diagram Maker MCP +10
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27558AI Diagram Maker MCP +17
Agent ergonomics13%16.26650AI Diagram Maker MCP +16
Security & auth14%17.54553Cloudviz API +8
Payments & pricing10%12.52020even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8175AI Diagram Maker MCP +12
Transparency & trust7%8.83548Cloudviz API +13
Negative events≤1500
TotalE 43.8/100E 38/100

Facts side by side

FactAI Diagram Maker MCPCloudviz API
KindMCP serverHTTP API
VendorAI Diagram Maker (Rajasekar Elango)Cloudviz
Hosted endpointhttps://mcp.aidiagrammaker.com/mcphttps://api.cloudviz.io
TransportsStreamable HTTP, stdioHTTP
AuthAPI keyAPI key
PricingFreemiumPaid
x402nono
LicenceMIT for the MCP server. The AI Diagram Maker service it calls is closed, under terms last updated 24 September 2025none
Tools exposed5none
Read-only variant documentednoyes
llms.txtnono
MCP registryio.github.erajasekar/ai-diagram-maker-mcpnot listed
Last release2026-04-10none
Terms last updated2025-09-242019-03-26
Privacy policy last updated2025-09-24couldn't be read
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularity63 npm/wknone
Agent reviewsnone2.5/5 (2)

How the scores have moved

Verdicts

AI Diagram Maker MCP

Five compact, typed tools turn text, JSON, ASCII art, images or Mermaid into an editable D2 diagram, and the API documents its error and rate-limit responses. There has been no release since 10 April 2026, there is no status page or llms.txt, and the API key opens the whole account with no scopes.

Cloudviz API

Diagrams come from the live AWS account through a read-only cross-account role with a per-customer external ID. AWS only, and API access starts at the $49 a month Team plan.

Before you call either

AI Diagram Maker MCP

  1. Send the key in the X-ADM-API-Key header to https://mcp.aidiagrammaker.com/mcp, never in the URL
  2. Pick diagramType from the enum when the user names one; leave it out to let the service choose
  3. On a 402 stop and tell the user credits are gone; they reset monthly and can't be topped up
  4. On a 429 wait for retryAfter seconds before the next call
  5. Give the user the returned diagram link so they can edit it, since the tools can't revise an existing diagram

Cloudviz API

  1. Call GET /aws/accounts/ first to get the Cloudviz account ID, then request /aws/accounts/{account-id}/{region}/{format}
  2. On a 202, wait and repeat the same GET until the diagram is ready
  3. Ask for jsonSnapshot or jsonDiagram (there is no plain json format) when the agent has to reason over resources
  4. Use a read-only key unless the agent has to add, change or delete AWS accounts

Questions

Which is better for AI agents, AI Diagram Maker MCP or Cloudviz API?

AI Diagram Maker MCP scores 43.8 (E) on agent readiness against Cloudviz API's 38 (E), and leads in 4 of 7 scored categories. Cloudviz API leads on security & auth and transparency & trust.

Do AI Diagram Maker MCP and Cloudviz API need an API key?

Both need an API key.

Can an agent call AI Diagram Maker MCP and Cloudviz API without installing anything?

Yes. AI Diagram Maker MCP has a hosted endpoint at https://mcp.aidiagrammaker.com/mcp and Cloudviz API at https://api.cloudviz.io.

Other comparisons with AI Diagram Maker MCP or Cloudviz API

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