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An E.V.I. is a pre-configured Theo client. Create it once, and every completion automatically includes your persona, skills, and tools.

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Create an E.V.I.

const evi = theo.evi({
  persona: "You are Nova, the AI assistant for WarehouseOS.",
  skills: ["data-extraction"],
  tools: [
    {
      name: "check_inventory",
      description: "Look up stock levels for a SKU",
      input_schema: {
        type: "object",
        properties: { sku: { type: "string" } },
        required: ["sku"],
      },
    },
  ],
  defaultMode: "auto",
  defaultTemperature: 0.7,
  metadata: { app: "warehouse-os" },
});

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Use It

// Persona, skills, and tools are injected automatically
const res = await evi.complete({ prompt: "Check stock for SKU-A1234" });
const stream = evi.stream({ prompt: "Generate inventory report" });

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EviConfig

FieldTypeRequiredDescription
personastring✅Custom system prompt — replaces Theo entirely
skillsstring[]—Skill slugs active on every completion
toolsToolDef[]—Inline tools available on every completion
defaultModeChatMode—Default mode (default: "auto")
defaultTemperaturenumber—Default temperature
metadataRecord<string, unknown>—Metadata on every request

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Merging Behavior

Per-request values are merged with E.V.I. defaults:
  • skills — E.V.I. skills + request skills (combined)
  • tools — E.V.I. tools + request tools (combined)
  • metadata — E.V.I. metadata merged with request metadata (request wins on conflicts)
  • mode — Request mode overrides E.V.I. default
  • temperature — Request temperature overrides E.V.I. default
// E.V.I. has skills: ["data-extraction"]
// This request adds "compliance-checker" for a total of both
const res = await evi.complete({
  prompt: "Check compliance for order #123",
  skills: ["compliance-checker"],
});