deepseek-ai/deepseek-harness · error · Error

harness.defineTool options must be an object

Error message

harness.defineTool options must be an object

What it means

Error "harness.defineTool options must be an object" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/extensions/cordis-host-runner/src/guard.ts:552

    return value as unknown as ContentBlock[]
  }
  throw new Error(
    `output.render returned ${describeReturn(value)} — it must return an ARRAY of content blocks:\n`
    + '  ✓ return [{ type: \'text\', text: String(value) }]',
  )
}

/**
 * The `harness.defineTool` handed into the sandbox: the real DSL, with `parameters` normalized
 * into a fresh host-realm ParameterSchemaSpec (raw object wrappers unwrapped,
 * required arrays mapped, and explicit DSL object openness enforced) and the tool's `execute` return normalized into the host realm
 * via a JSON round-trip. Non-JSON or wrong-shape output fails that call instead of poisoning
 * the session log.
 * @param options - the standard `defineTool` options; `parameters` may be the ParameterSchemaSpec DSL or a JSON-Schema-style wrapper.
 * @returns the marker-tagged definition `harness.registerTool` (and the guarded `ctx.tools.register`) accepts.
 */
export function sandboxDefineTool(options: unknown): ToolDefinition {
  if (!isPlainRecord(options)) throw new Error('harness.defineTool options must be an object')
  const normalized = normalizeParameterSchemaSpec(options.parameters)
  if (!isPlainRecord(options.output)) {
    throw new Error('harness.defineTool output must declare { schema, render, presentationMeta? }')
  }
  const output = options.output
  if (typeof output.render !== 'function') throw new Error('harness.defineTool output.render must be a function')
  if (output.presentationMeta !== undefined && typeof output.presentationMeta !== 'function') {
    throw new Error('harness.defineTool output.presentationMeta must be a function when present')
  }
  if (typeof options.execute !== 'function') throw new Error('harness.defineTool execute must be a function')
  const schema = cloneJson(output.schema, 'harness.defineTool output.schema')
  const rawExecute = options.execute as (args: unknown, exec: unknown) => Promise<unknown>
  const rawRender = output.render as (args: unknown, value: unknown) => unknown
  const rawPresentationMeta = output.presentationMeta as ((args: unknown, value: unknown) => unknown) | undefined
  const erasedDefineTool = defineTool as unknown as (definition: unknown) => ToolDefinition
  const tool = erasedDefineTool({
    ...options,
    parameters: normalized.spec,

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/extensions/cordis-host-runner/src/guard.ts:552 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/4517c7aaf197a108. Report an issue: GitHub.