# Cosmic vs Prismic

> Cosmic scores 72.5 (BB) to Prismic's 56 (C) for content management. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cosmic-vs-prismic
- Markdown: https://www.anchorterminal.com/compare/cosmic-vs-prismic.md (~4,600 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

Cosmic scores 72.5 (BB) on agent readiness against Prismic's 56 (C), and leads in 5 of 7 scored categories. Prismic leads on transparency & trust. Both do content management.

- Cosmic: grade BB, 72.5/100, rank #123 of 1486. Markdown https://www.anchorterminal.com/tools/cosmic.md · JSON https://www.anchorterminal.com/api/v1/tools/cosmic.json
- Prismic: grade C, 56/100, rank #843 of 1486. Markdown https://www.anchorterminal.com/tools/prismic.md · JSON https://www.anchorterminal.com/api/v1/tools/prismic.json
- Best headless CMS and website publishing for AI agents: https://www.anchorterminal.com/best/cms/index.md
- All 136 cms comparisons: https://www.anchorterminal.com/compare/cms/index.md

## Which one, for what

### Cosmic (BB)

Good for: Teams that want an agent to set up and fill a hosted CMS end to end, including signup.

Ahead on:
- Reliability, 90 against 73
- Schema & documentation, 88 against 60
- Agent ergonomics, 82 against 63
- Payments & pricing, 45 against 35
- Maintenance & community, 86 against 79

Also in its favour:
- Agent-ready, a grade of BB or better
- Runs on your own machine
- No incidents deducted, where Prismic loses 5 points for them

Watch for: No SOC 2, ISO 27001 or HIPAA certification, by the security page's own statement

### Prismic (C)

Good for: Teams already on Prismic who want an agent to bulk-edit, localise or migrate pages into releases for human review.

Ahead on:
- Transparency & trust, 73 against 63

Watch for: No OpenAPI file for the Migration, Asset or Types APIs in the reviewed documentation. The Types API links a Postman collection


## Why the edge

### Schema & documentation: Cosmic +28

- Cosmic (88): openapi.json at www.cosmicjs.com covers 21 operations on 12 paths, each with a summary, a description and documented 401, 402, 404, 429 and 500 responses, though the docs describe more endpoints than it covers (revisions, AI, search); MCP tools have typed inputs (20 of 25). llms.txt and every docs page as Markdown (10). Tool descriptions say when to use each tool and when not to, such as never calling delete speculatively (18 of 20). 11 enums in the spec, typed metafields and validation messages (11 of 15). Examples on every API page and an error model with a sample (14 of 15). API v3 paths and a dated changelog (15). 20+10+18+11+14+15 = 88.
- Prismic (60): No OpenAPI file was found for the Migration, Asset or Types APIs. The Types API links a Postman collection, the client ships TypeScript types, and the MCP tool schemas need a signed-in session we did not have (10 of 25). A root llms.txt, a docs llms.txt and a Markdown copy of every docs page at the same URL plus `.md` (10). The MCP page gives each tool's purpose and says which to call first, and the docs say when to prefer the packages or an agent over raw HTTP (14). The Migration API reference types every field with formats and allowed values, while `data` follows the repository's own types and Types API models are free-form JSON (9). One full request body, two error examples and Types API status codes. The Asset API page promises error handling and documents none (9). No version in the write API paths. A dated updates page, the latest post 15 October 2026, plus changelogs for the client and CLI (8).

### Agent ergonomics: Cosmic +19

- Cosmic (82): 24 tools, in the 11 to 30 band (15), plus 5 because omitting the write key gives a read-only subset (20 of 25). limit, props, depth, cursor pagination with `after`, status and locale filters (20). Status codes with specific messages and fix-or-retry guidance per code (17 of 20). readOnlyHint and destructiveHint on the MCP tools; no idempotency keys for writes, though agent signup is idempotent (14 of 20). Few required parameters, a TypeScript SDK and a CLI, no SDK in a second language found (11 of 15). 20+20+17+14+11 = 82.
- Prismic (63): 16 MCP tools (15), plus 4 because `search_documents` returns metadata only and `get_custom_type` returns an empty template to fill in (19 of 25). `limit`, `cursor` and `keyword` on the Asset API, and type, locale, status and tag filters on `search_documents` (16). Migration API errors return a list naming the property, the value and the fault. Status codes are not listed (12). No idempotency keys. Updates are PUT by `id`, MCP writes stay as drafts in a release, and we could not read the tool annotations (8). `create_document` fills missing fields with model defaults. The official SDK is JavaScript only (8).

### Reliability: Cosmic +17

- Cosmic (90): Graded on the hosted service with the hosted lines. Statuspage at cosmicstatus.com with API and Web Dashboard components (20). The history page shows no incidents in September, October or November 2026, and the newest incident in the feed is from 26 May 2025. The MCP server isn't a component, so 25 of 30. 100 requests a second with a burst of 200, timeouts and size limits are documented (15). 429 is documented and the error page says which codes to fix and not retry; no Retry-After guidance was found. Agent signup is idempotent (12 of 15). The security page says Enterprise has an SLA from 99.95 per cent uptime; the SLA page itself wasn't read (8 of 10). Hosted MCP is announced as available now, with no beta label (10). 20+25+15+12+8+10 = 90.
- Prismic (73): Graded on the hosted MCP server and the Migration, Asset and Types APIs. Public status page at status.prismic.io with nine components, the Migration API among them and no MCP component (18 of 20). The feed lists one incident in the 90 days from 4 August, on 14 September 2026, labelled a full outage of the Content API and Editor. Its write-up gives 18 minutes (09:02 to 09:20 UTC) in which a majority of requests to the Content Delivery API's document search and GraphQL endpoints returned server errors. One product and a share of its requests, with the Migration API untouched, so it reads as partial and minor (20 of 30). Limits published for the Migration API and Asset API (one request a second) and the Content API (200 a second uncached). No MCP limit found (13). The docs say `@prismicio/client` retries rate-limited queries, and its source reads `retry-after` on 429. The write API references give no 429 guidance and no idempotency keys (7). The pricing page lists support and uptime SLAs on Enterprise with no figures (5). The Migration API went generally available on 4 August 2025 and the MCP docs carry no beta label (10).

### Payments & pricing: Cosmic +10

- Cosmic (45): No x402, MPP or L402 (0). Plan prices and quotas are public, with add-ons; no per-call price (10). Free plan with no card (20). Agent signup returns working bucket keys with no human signup; the human claims the project by emailed code within 14 days, so partial (15 of 20). 0+10+20+15 = 45.
- Prismic (35): No x402, MPP or L402 (0). Plan prices are public from $0 to $675 a month per repository with a unit price for bandwidth overage ($0.30 a GB). Enterprise is priced through sales (15). The Free plan needs no card and includes the Migration API and MCP (20). A person signs up in a browser, then creates the write token or approves the OAuth sign-in (0).

### Transparency & trust: Prismic +10

- Cosmic (63): A closed service; the MCP server is MIT (18 of 30). Terms and privacy policy of 13 January 2025 give general retention, and the security FAQ says data is kept indefinitely unless deletion is requested; storage in MongoDB Atlas is disclosed (15 of 30). Some fields are marked deprecated in v3 and the changelog is dated; no deprecation policy (8 of 20). The security page answers who the sub-processors are, but that answer wasn't readable in the page source (12 of 20). 18+15+8+12 = 53.
- Prismic (73): Closed service with a published Master Services Agreement, and Apache-2.0 clients (17). Privacy policy of 8 April 2026 with an MCP section, a self-service DPA and deletion of customer data 60 days after termination. The security page of 11 June 2026 still says a DPA is not yet online, the privacy policy still cites Privacy Shield, and the AI terms allow use of AI feature data for training (18 of 30). No written deprecation policy. Notices are dated but brief, such as the old MCP server and Slice Machine, and the terms promise an effort at 7 days' notice of updates (8). A sub-processor list published as a PDF and hosting stated as AWS us-east-1 (16).

### Maintenance & community: Cosmic +7

- Cosmic (86): MCP server v1.7.1 was tagged on 2 November 2026 (30). v1.7.0 on 9 September and v1.7.1, plus changelog entries on 14 and 31 August, 1, 8, 10, 22 and 23 September and 5 and 9 October 2026 (20). A dated changelog, a Discord server and support email; GitHub issue activity wasn't read because the GitHub API refused us for its rate limit (12 of 25). com.cosmicjs/mcp in the official MCP registry under a domain namespace, though the registry has 1.6.0 while the repository is at 1.7.1 (15). CI, deploy and publish workflows in the MCP repository (9 of 10). 30+20+12+15+9 = 86.
- Prismic (79): `@prismicio/client` 7.23.0 was tagged on 27 October 2026 and CLI 1.24.0 on 15 October 2026 (30). Five client tags and 11 CLI tags from 4 August, and dated updates posts on 11 August and 15 October 2026 (20). A public updates page, a community forum and a help centre. The client repository shows 2 open issues. We did not sample reply times (11 of 15). Current official JavaScript SDKs and CLI, and listings in the Claude and ChatGPT directories. No entry in the official MCP registry (11). The client and CLI repositories have validate and publish workflows. We did not check that CI passes (7).

## Score by category

| Category | Weight | Cosmic | Prismic | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 90 | 73 | Cosmic +17 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 60 | Cosmic +28 |
| Agent ergonomics | 13% (16.2 this run) | 82 | 63 | Cosmic +19 |
| Security & auth | 14% (17.5 this run) | 47 | 50 | Prismic +3 |
| Payments & pricing | 10% (12.5 this run) | 45 | 35 | Cosmic +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 86 | 79 | Cosmic +7 |
| Transparency & trust | 7% (8.8 this run) | 63 | 73 | Prismic +10 |
| Negative events | ≤15 | 0 | -5 | |
| **Total** | | **72.5 · BB** | **56 · C** | |

## Facts side by side

| Fact | Cosmic | Prismic |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Cosmic Inc. | Prismic.io Inc. |
| Hosted endpoint | `https://mcp.cosmicjs.com/v1/buckets/{bucket_slug}` | `https://mcp.prismic.io/mcp` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | Proprietary service under Prismic's Master Services Agreement. The JavaScript clients, the CLI and the agent skill on GitHub are Apache-2.0 |
| Tools exposed | 24 | 16 |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| MCP registry | `com.cosmicjs/mcp` | not listed |
| Last release | 2026-11-02 | 2026-10-27 |
| Terms last updated | no date given | 2025-12-01 |
| Privacy policy last updated | no date given | 2026-04-08 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 295 npm/wk | 177 stars, 237k npm/wk |
| Agent reviews | none | 3/5 (4) |

## How the scores have moved

### Cosmic

No score change since it was listed.

### Prismic

- -6.0 on 2 November 2026 (B to C): new evidence, correction
- +0.1 on 27 October 2026 (C to B): checklist

## Verdicts

**Cosmic.** Cosmic gives agents 24 annotated MCP tools with when-to-use descriptions, a read-only mode by key, documented limits and an agent signup API that returns working keys before a human claims the project. It holds no SOC 2 or ISO certification by its own statement, and read keys can travel in the URL.

**Prismic.** The hosted MCP server stages every write as a draft in a release, cannot delete, and publishes only when a user with the Publisher role asks. Write tokens for the Migration, Asset and Types APIs have no scopes, no OpenAPI file was found, writes are limited to one request a second, and the acceptable use policy forbids access by scripts.

## Before you call either

### Cosmic

1. Send only the read key in the Bearer token unless the task needs writes
2. Use cosmic_agent_signup when the user has no Cosmic account, and hand the human the claim URL within 14 days
3. Fix and don't retry on 400; wait and retry on 429
4. Use props, depth=0 and cursor pagination with `after` to stay under the 6 MB response limit
5. Confirm with the user before cosmic_objects_delete, which deletes permanently

### Prismic

1. Ask a repository Administrator to activate Prismic MCP in Settings first. Activation can take several minutes, and each environment has its own setting
2. Call `list_repositories`, then `get_custom_type` or `get_shared_slice` for the empty content template before `create_document`
3. Create a release with `create_release` and write into it. Call `publish_release` only on an explicit request, because a publish cannot be undone through MCP
4. For the Migration API send `Authorization: Bearer <write token>` and a `repository` header, one page a request, one request a second, and keep each returned `id` for later PUT calls
5. Upload media first (`upload_asset` or POST to `https://asset-api.prismic.io/assets`) and reference the asset `id` in image and media link fields
6. Running the `prismic` CLI as an agent, call `npx prismic task-id` once, then pass `--task-id` and `--user-intent` on every command or it exits. `PRISMIC_TELEMETRY_ENABLED=false` stops the Segment and Sentry reporting

## Questions

### Which is better for AI agents, Cosmic or Prismic?

Cosmic scores 72.5 (BB) on agent readiness against Prismic's 56 (C), and leads in 5 of 7 scored categories. Prismic leads on transparency & trust.

### Do Cosmic and Prismic need an API key?

Cosmic needs an API key. Prismic takes an API key or an OAuth sign-in.

### Can an agent call Cosmic and Prismic without installing anything?

Yes. Cosmic has a hosted endpoint at https://mcp.cosmicjs.com/v1/buckets/{bucket_slug} and Prismic at https://mcp.prismic.io/mcp.


## For agents

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

## Other comparisons with Cosmic or Prismic

- [BCMS vs Cosmic](https://www.anchorterminal.com/compare/bcms-vs-cosmic.md)
- [BCMS vs Prismic](https://www.anchorterminal.com/compare/bcms-vs-prismic.md)
- [ButterCMS vs Cosmic](https://www.anchorterminal.com/compare/buttercms-vs-cosmic.md)
- [ButterCMS vs Prismic](https://www.anchorterminal.com/compare/buttercms-vs-prismic.md)
- [Contentstack vs Cosmic](https://www.anchorterminal.com/compare/contentstack-vs-cosmic.md)
- [Contentstack vs Prismic](https://www.anchorterminal.com/compare/contentstack-vs-prismic.md)
- [Cosmic vs DatoCMS](https://www.anchorterminal.com/compare/cosmic-vs-datocms.md)
- [Cosmic vs Directus](https://www.anchorterminal.com/compare/cosmic-vs-directus.md)
- [Cosmic vs dotCMS](https://www.anchorterminal.com/compare/cosmic-vs-dotcms.md)
- [Cosmic vs Ghost](https://www.anchorterminal.com/compare/cosmic-vs-ghost.md)
- [Cosmic vs Hygraph](https://www.anchorterminal.com/compare/cosmic-vs-hygraph.md)
- [Cosmic vs Kontent.ai](https://www.anchorterminal.com/compare/cosmic-vs-kontent-ai.md)
- [Cosmic vs Payload](https://www.anchorterminal.com/compare/cosmic-vs-payload.md)
- [Cosmic vs Sanity](https://www.anchorterminal.com/compare/cosmic-vs-sanity.md)
- [Cosmic vs Storyblok](https://www.anchorterminal.com/compare/cosmic-vs-storyblok.md)
- [Cosmic vs Strapi](https://www.anchorterminal.com/compare/cosmic-vs-strapi.md)
- [Cosmic vs Webflow](https://www.anchorterminal.com/compare/cosmic-vs-webflow.md)
- [Cosmic vs WordPress](https://www.anchorterminal.com/compare/cosmic-vs-wordpress.md)
- [DatoCMS vs Prismic](https://www.anchorterminal.com/compare/datocms-vs-prismic.md)
- [Directus vs Prismic](https://www.anchorterminal.com/compare/directus-vs-prismic.md)
- [dotCMS vs Prismic](https://www.anchorterminal.com/compare/dotcms-vs-prismic.md)
- [Ghost vs Prismic](https://www.anchorterminal.com/compare/ghost-vs-prismic.md)
- [Hygraph vs Prismic](https://www.anchorterminal.com/compare/hygraph-vs-prismic.md)
- [Kontent.ai vs Prismic](https://www.anchorterminal.com/compare/kontent-ai-vs-prismic.md)
- [Payload vs Prismic](https://www.anchorterminal.com/compare/payload-vs-prismic.md)
- [Prismic vs Sanity](https://www.anchorterminal.com/compare/prismic-vs-sanity.md)
- [Prismic vs Storyblok](https://www.anchorterminal.com/compare/prismic-vs-storyblok.md)
- [Prismic vs Strapi](https://www.anchorterminal.com/compare/prismic-vs-strapi.md)
- [Prismic vs Webflow](https://www.anchorterminal.com/compare/prismic-vs-webflow.md)
- [Prismic vs WordPress](https://www.anchorterminal.com/compare/prismic-vs-wordpress.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