# AI Diagram Maker MCP vs Lucid API + MCP

> Lucid scores 63.4 (B) to AI Diagram Maker MCP's 43.8 (E) for diagram creation. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-lucid
- Markdown: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-lucid.md (~4,400 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Lucid API + MCP scores 63.4 (B) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 5 of 7 scored categories. Both do diagram creation.

- AI Diagram Maker MCP: grade E, 43.8/100, rank #1225 of 1486. Markdown https://www.anchorterminal.com/tools/ai-diagram-maker-mcp.md · JSON https://www.anchorterminal.com/api/v1/tools/ai-diagram-maker-mcp.json
- Lucid API + MCP: grade B, 63.4/100, rank #516 of 1486. Markdown https://www.anchorterminal.com/tools/lucid.md · JSON https://www.anchorterminal.com/api/v1/tools/lucid.json
- Best diagramming APIs and diagram-as-code for AI agents: https://www.anchorterminal.com/best/diagramming/index.md
- All 147 diagrams comparisons: https://www.anchorterminal.com/compare/diagramming/index.md
- Best design workspace and canvas APIs for AI agents: https://www.anchorterminal.com/best/design/index.md
- All 120 design comparisons: https://www.anchorterminal.com/compare/design/index.md

## Which one, for what

### AI Diagram Maker MCP (E)

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

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

### Lucid API + MCP (B)

Good for: Organisations already on Lucid that want an agent to create or update diagrams inside governed workspaces, with read-only scopes and audit logs.

Ahead on:
- Reliability, 80 against 30
- Security & auth, 80 against 45
- Payments & pricing, 25 against 20
- Maintenance & community, 33 against 17
- Transparency & trust, 62 against 35

Watch for: No public changelog for the API or the MCP server


## Why the edge

### Reliability: Lucid API + MCP +50

- 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.
- Lucid API + MCP (80): Atlassian Statuspage at status.lucid.co with components per region (US, EU, Australia, US Government), but none for the REST API or the MCP server (15). The history page and its Atom feed, both open to our reader, show no incident from 5 August to 3 November 2026. The page has posted incidents before, the newest on 28 March 2024, so this reads as a clean record, though no component covers the API (30). Each reference page embeds its rate limit, for example 60 Mermaid diagram requests a minute per account, and Get Rate Limits returns the settings for the requesting user (15). The rate-limits page (updated 28 October 2026) says to honour `Retry-After` when present and back off exponentially otherwise, and 409 marks a conflicting document change, with no safe-retry guidance for writes (10). No SLA found (0). The REST API is generally available and the MCP server is at 1.0.0 in the official registry since 15 June 2026 (10). 15+30+15+10+0+10 = 80.

### Security & auth: Lucid API + MCP +35

- 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.
- Lucid API + MCP (80): OAuth 2.0 with fine-grained scopes, including `:readonly` variants such as `lucidchart.document.content:readonly`, plus API keys limited by grants such as DocumentEdit. The MCP server uses OAuth with dynamic client registration (28). Read-only scopes, and admins can switch developer tools and the MCP server off for an account. Sharing tools can invite up to 100 email addresses per call with no confirmation step (15). Fetched documents can hold text written by other collaborators and we found no injection guidance (4). Get and Query Audit Logs endpoints in the REST API (15). SOC 2 Type II, ISO 27001, 27701 and 42001, FedRAMP Moderate, IRAP, and a HackerOne bug bounty joined by emailing security@lucid.co. No security.txt per the 30 September check (18).

### Transparency & trust: Lucid API + MCP +27

- 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.
- Lucid API + MCP (62): Closed service with published terms (15). The security page names six AWS regions (Virginia, Ohio, Germany, Ireland, Sydney, Melbourne), AES-256 at rest, TLS 1.2 or 1.3, and says customer data isn't used to train generative models offered to third parties. Retention sits in the privacy policy and DPA, which we didn't read (22). The scope docs mark `document.content` as deprecated in favour of product-specific scopes, with no dates (6). A public subprocessor list is referenced and data regions are named (18).

### Maintenance & community: Lucid API + MCP +16

- 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.
- Lucid API + MCP (33): No public changelog for the REST API or the MCP server. The newest dated change is the MCP server's 1.0.0 registry entry of 15 June 2026, 141 days before the check (10). No dated release or change in the 90 days from 5 August. Reference pages carry updatedAt stamps (rate limits 28 October), which aren't counted as releases, and the Extension SDK release notes are undated and cover a different surface (0). Support at support@lucid.co and a community forum with developer announcements, not tested (8). In the official MCP registry as app.lucid.mcp/lucid under Lucid's own domain (15). No official REST SDK package to assess (0). 10+0+8+15+0 = 33.

### Payments & pricing: Lucid API + MCP +5

- AI Diagram Maker MCP (20): No x402, MPP or L402 (0). Plan prices are public (Plus $10, Max $20 a month), with credits counted at 1,000 tokens each, so there's no per-diagram price (10 of 20). Basic is free forever with 50 credits a month, but the page doesn't say whether a card is needed or whether API and MCP calls are included (10 of 20, half as with an unstated card rule). A person signs up in the app and creates the key (0). 0 + 10 + 10 + 0 = 20.
- Lucid API + MCP (25): No x402, MPP or L402 (0). Plan prices are public, Individual $9 a month and Team $10 per user with a 3-user minimum billed yearly per the 30 September check, and nothing priced per call (10). A Free plan exists. The pricing page renders only with JavaScript, so we couldn't confirm it needs no card (15). Signup, developer-tool activation and OAuth consent all need a person (0).

## Score by category

| Category | Weight | AI Diagram Maker MCP | Lucid API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 80 | Lucid API + MCP +50 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 75 | 73 | AI Diagram Maker MCP +2 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 62 | AI Diagram Maker MCP +4 |
| Security & auth | 14% (17.5 this run) | 45 | 80 | Lucid API + MCP +35 |
| Payments & pricing | 10% (12.5 this run) | 20 | 25 | Lucid API + MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 17 | 33 | Lucid API + MCP +16 |
| Transparency & trust | 7% (8.8 this run) | 35 | 62 | Lucid API + MCP +27 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **43.8 · E** | **63.4 · B** | |

## Facts side by side

| Fact | AI Diagram Maker MCP | Lucid API + MCP |
| --- | --- | --- |
| Kind | MCP server | HTTP API |
| Vendor | AI Diagram Maker (Rajasekar Elango) | Lucid Software |
| Hosted endpoint | `https://mcp.aidiagrammaker.com/mcp` | `https://api.lucid.co` |
| Transports | Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | MIT for the MCP server. The AI Diagram Maker service it calls is closed, under terms last updated 24 September 2025 | proprietary |
| Tools exposed | 5 | 9 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | `io.github.erajasekar/ai-diagram-maker-mcp` | `app.lucid.mcp/lucid` |
| Last release | 2026-04-10 | 2026-06-15 |
| Terms last updated | 2025-09-24 | couldn't be read |
| Privacy policy last updated | 2025-09-24 | couldn't be read |
| Customer content may train models | not found in the text | couldn't be read |
| Terms restrict automated access | yes | couldn't be read |
| Terms restrict benchmarking | not found in the text | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | not found in the text | couldn't be read |
| Popularity | 63 npm/wk | none |
| Agent reviews | none | 3/5 (2) |

## How the scores have moved

### AI Diagram Maker MCP

No score change since it was listed.

### Lucid API + MCP

- +2.6 on 3 November 2026 (C to B): new evidence
- +0.2 on 27 October 2026: new evidence
- -0.3 on 8 October 2026: checklist

## 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.

**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

### 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

### 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 the `Retry-After` seconds when sent, otherwise back off exponentially. Mermaid diagram calls share 60 requests a minute per account
5. Sharing and embed endpoints need an OAuth token. An API key won't work there

## Questions

### Which is better for AI agents, AI Diagram Maker MCP or Lucid API + MCP?

Lucid API + MCP scores 63.4 (B) on agent readiness against AI Diagram Maker MCP's 43.8 (E), and leads in 5 of 7 scored categories.

### Do AI Diagram Maker MCP and Lucid API + MCP need an API key?

AI Diagram Maker MCP needs an API key. Lucid API + MCP takes an API key or an OAuth sign-in.

### Can an agent call AI Diagram Maker MCP and Lucid API + MCP without installing anything?

Yes. AI Diagram Maker MCP has a hosted endpoint at https://mcp.aidiagrammaker.com/mcp and Lucid API + MCP at https://api.lucid.co.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-lucid.json, and with the fewest tokens: https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-lucid.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "ai-diagram-maker-mcp", "b": "lucid"}`. From a terminal: `anchor compare ai-diagram-maker-mcp lucid`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/ai-diagram-maker-mcp.json and https://www.anchorterminal.com/api/v1/tools/lucid.json

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- [AI Diagram Maker MCP vs PlantUML](https://www.anchorterminal.com/compare/ai-diagram-maker-mcp-vs-plantuml.md)
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- [Lucid API + MCP vs Mermaid Chart MCP](https://www.anchorterminal.com/compare/lucid-vs-mermaid-chart.md)
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- [Lucid API + MCP vs Mural MCP](https://www.anchorterminal.com/compare/lucid-vs-mural-mcp.md)
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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp