# Muse Spark Open vs Prism Inference

> Prism Inference scores 60.1 (C) to Muse Spark Open's 53.4 (D) for llm inference. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-15

Prism Inference scores 60.1 (C) on agent readiness against Muse Spark Open's 53.4 (D), and leads in 4 of 7 scored categories. Muse Spark Open leads on payments & pricing and maintenance & community. Both do llm inference.

- Muse Spark Open: grade D, 53.4/100, rank #760 of 1095. Markdown https://www.anchorterminal.com/tools/muse-spark-open.md · JSON https://www.anchorterminal.com/api/v1/tools/muse-spark-open.json
- Prism Inference: grade C, 60.1/100, rank #563 of 1095. Markdown https://www.anchorterminal.com/tools/prism-inference.md · JSON https://www.anchorterminal.com/api/v1/tools/prism-inference.json
- Best model APIs and inference for AI agents: https://www.anchorterminal.com/best/inference/index.md
- All 210 models comparisons: https://www.anchorterminal.com/compare/inference/index.md

## Which one, for what

### Muse Spark Open (D)

Good for: A team with a four-GPU Blackwell node, or two to four Mac Studios, that wants a 1M-token multimodal coding and agent model on its own hardware with no prompts leaving it.

Ahead on:
- Payments & pricing, 50 against 30
- Maintenance & community, 60 against 49

Also in its favour:
- No key needed to call it

Watch for: The NVFP4 checkpoint (about 537 GB) serves on four B300 GPUs and the BF16 one (about 1.65 TB) on eight

### Prism Inference (C)

Good for: Coding agents that want DeepSeek-V4.1-Flash at a low input price, with no retention, through whichever of the three wire formats the harness already speaks.

Ahead on:
- Reliability, 65 against 42
- Schema & documentation, 82 against 61
- Security & auth, 65 against 44
- Transparency & trust, 61 against 53

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: Two models. The docs mark Gemma 4 31B as request access per organisation, while llms.txt and the keyless catalogue list it as available


## Score by category

| Category | Weight | Muse Spark Open | Prism Inference | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 42 | 65 | Prism Inference +23 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 61 | 82 | Prism Inference +21 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 68 | Muse Spark Open +1 |
| Security & auth | 14% (17.5 this run) | 44 | 65 | Prism Inference +21 |
| Payments & pricing | 10% (12.5 this run) | 50 | 30 | Muse Spark Open +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 60 | 49 | Muse Spark Open +11 |
| Transparency & trust | 7% (8.8 this run) | 53 | 61 | Prism Inference +8 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **53.4 · D** | **60.1 · C** | |

## Facts side by side

| Fact | Muse Spark Open | Prism Inference |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Meta | Prism Technologies Inc |
| Hosted endpoint | no (local only) | `https://api.prisminference.com/v1` |
| Transports | HTTP | HTTP |
| Auth | None | API key |
| Pricing | Free | Pay per use |
| x402 | no | no |
| Licence | Muse Model Licence (source-available weights, not an OSI licence), free of charge with an attribution notice, a separate agreement with Meta before Model as a Service by a licensee group above $20M gross revenue, and the Muse Spark Open Usage Policy | Proprietary service under Prism's terms of service. The OpenAPI file declares `LicenseRef-Proprietary`. The Hermes provider plugin repository carries no licence file |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-15 | 2026-10-06 |
| Terms last updated |  | 2026-09-09 |
| Privacy policy last updated | no document linked | 2026-09-09 |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | not found in the text |
| Terms or service can change without notice |  | not found in the text |
| Arbitration or class-action waiver |  | yes |

## Verdicts

**Muse Spark Open.** Muse Spark Open runs on the owner's hardware in seven runtimes, with OpenAI-compatible servers in vLLM and SGLang, standard tool calls, a 1M-token context and Meta's own serving docs. Serving the 537 GB NVFP4 checkpoint takes four B300 GPUs, Meta's download is gated by manual review, and the licence adds attribution and a revenue threshold for model resellers.

**Prism Inference.** Three wire formats, a public OpenAPI 3.1 file, per-token prices in a keyless catalogue and zero data retention by default on every tier. The service launched on 24 September 2026 with two models, one of them by request, from a two-person company. No rate-limit numbers, SLA document, free tier or deprecation policy was found.

## Before you call either

### Muse Spark Open

1. Start vLLM or SGLang with `--reasoning-parser muse --tool-call-parser muse` (vLLM also `--enable-auto-tool-choice`), or tool calls come back as raw text
2. Set `reasoning_effort` to `low` or `medium` for short tasks. The default is `xhigh`, reasoning can't be turned off, and other values return an error
3. Stop only on `<|eot|>` and end of text. Stopping on `<|eom|>` cuts off tool calls and final answers
4. Stream long generations and leave `max_tokens` room for reasoning, or `content` can come back empty with `finish_reason` `length`
5. Don't call Meta Model API for this model. Use a self-hosted server or a hosted provider's model string, such as `meta-models/muse-spark-open`

### Prism Inference

1. Call `GET https://api.prisminference.com/v1/models` at start-up, with no key, and use only ids it returns. Expect 403 on `gemma-4-31b` without organisation access
2. Use base URL `https://api.prisminference.com/v1` for OpenAI clients and `https://api.prisminference.com` with no `/v1` for Anthropic clients
3. Read `error.retryable` before retrying, and wait for `Retry-After` on 429, which covers both key limits and model capacity
4. Send `reasoning_effort: "none"` or `low` when latency matters. Reasoning is on by default and its tokens are billed as output
5. Keep conversation state yourself and send `store: false` on Responses. `previous_response_id`, stored responses and hosted tools aren't supported

## Questions

### Which is better for AI agents, Muse Spark Open or Prism Inference?

Prism Inference scores 60.1 (C) on agent readiness against Muse Spark Open's 53.4 (D), and leads in 4 of 7 scored categories. Muse Spark Open leads on payments & pricing and maintenance & community.

### Do Muse Spark Open and Prism Inference need an API key?

Muse Spark Open needs no key. Prism Inference needs an API key.

### Can an agent call Muse Spark Open and Prism Inference without installing anything?

No hosted endpoint is listed for Muse Spark Open. Prism Inference has a hosted endpoint at https://api.prisminference.com/v1.


## For agents

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

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- [Claude API vs Muse Spark Open](https://www.anchorterminal.com/compare/anthropic-api-vs-muse-spark-open.md)
- [Claude API vs Prism Inference](https://www.anchorterminal.com/compare/anthropic-api-vs-prism-inference.md)
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