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The PRYSM Model Context Protocol server lets any MCP client — Claude Desktop, Cursor, Windsurf, and others — route prompts to the best-value model among 19, preview costs, validate a BRAIN.md, and read usage. Your agent shouldn’t burn a frontier model on a one-line task; point it at PRYSM and it can pick the cheapest model that does the job well — no provider keys to juggle, one bill, one receipt per call.

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Install

No global install needed — your MCP client launches it on demand with npx.
Add to claude_desktop_config.json:
{
  "mcpServers": {
    "prysm": {
      "command": "npx",
      "args": ["-y", "@prysmai/mcp"],
      "env": {
        "PRYSM_API_KEY": "prysm_sk_your_key",
        "PRYSM_BASE_URL": "https://api.prysm1.com/v1"
      }
    }
  }
}
Restart your client after editing the config; “prysm” then appears as a tool provider.

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Tools

ToolWhat it does
prysm_routePreview which model PRYSM would pick + estimated cost — no model call.
prysm_chatRoute a prompt to the best model and return the answer (+ model, cost, proof).
prysm_orchestrateCross several models (cascade / ensemble / debate) for one robust answer + agreement score and PrysmProof. Accepts a compliance spec to confine the run to approved providers.
prysm_codeGenerate code with a self-correcting coder + critic loop — returns reviewed, repaired files + PrysmProof.
prysm_compliance_previewDry-run the Policy-as-Code compliance gate — no model call. Shows the data classes a prompt triggers, which models are allowed vs excluded under the org policy, the Compliance Cost Premium, and a sample attestation.
prysm_modelsList the 19-model catalog with live pricing, tier, and context window.
prysm_brain_validateValidate a BRAIN.md routing config against the catalog + schema.
prysm_usageUsage stats for the configured key: requests, tokens, cost.
A great agent pattern: call prysm_route first to see the cost, then prysm_chat to execute — so the agent reasons about spend before committing to a model.

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Configuration

Env varDefaultDescription
PRYSM_API_KEY—Your prysm_sk_* key (required for prysm_chat / prysm_usage).
PRYSM_BASE_URLhttps://api.prysm1.com/v1API base URL (point at a self-hosted instance if needed).
The server communicates over stdio — the standard MCP transport. All diagnostics go to stderr, keeping the protocol channel clean.

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What your agent gains

Cost-aware by default

The agent previews the price of a task and routes to the cheapest capable model.

One key, every model

21 models across 9 providers behind a single PRYSM key — no per-provider setup.

Governed by BRAIN.md

The same BRAIN.md rules and guardrails apply to agent calls.

Verifiable

Every prysm_chat returns a PrysmProof of what ran.