deepseek-ai/deepseek-harness · error · Error

invalid todos: at most one task may be in_progress (got ${ac

Error message

invalid todos: at most one task may be in_progress (got ${active})

What it means

Error "invalid todos: at most one task may be in_progress (got ${active})" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/todo/tool-todo/src/index.ts:108

 */
function toTodoList(raw: { content: string; status: string }[], allowParallel: boolean): TodoItem[] {
  const todos: TodoItem[] = []
  const seen = new Set<string>()
  let active = 0
  for (const item of raw) {
    const content = item.content.trim()
    if (content.length === 0) {
      throw new Error('invalid todo: `content` must be a non-empty string')
    }
    if (seen.has(content)) {
      throw new Error(`invalid todos: duplicate content ${JSON.stringify(content)}`)
    }
    seen.add(content)
    if (item.status === 'in_progress') active++
    todos.push({ content, status: item.status as TodoItem['status'] })
  }
  if (!allowParallel && active > 1) {
    throw new Error(`invalid todos: at most one task may be in_progress (got ${active})`)
  }
  return todos
}

/** Wire payload schema of the `todos` projection (whole list or pre-first-write null). */
const todosProjectionSchema: ZodType<TodoItem[] | null> = zod.union([
  zod.array(zod.object({
    content: zod.string(),
    status: zod.union([zod.literal('pending'), zod.literal('in_progress'), zod.literal('completed')]),
  })),
  zod.null(),
])

/**
 * Register the `todo_write` tool on `ctx.tools` and, when the session-projection seam is composed,
 * the `todos` unit.
 * @param ctx - registrant context carrying the tool registry.
 * @param config - deployment's explicit todo policy.

View on GitHub (pinned to b150a551b8)

Solutions

1. Mark at most one task in_progress; move the others back to pending.

When it happens

Trigger: Thrown at packages/todo/tool-todo/src/index.ts:108 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/4c2b70b114cabe87. Report an issue: GitHub.