deepseek-ai/deepseek-harness · error · Error

session header is not a plain JSON record

Error message

session header is not a plain JSON record

What it means

Error "session header is not a plain JSON record" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/index.ts:98

     * (`@deepseek-ai/dsh-scope`) reuses the session's owner scope.
     * @param session - the session whose buffered events must reach durable storage.
     * @dshScopeScan unsupported
     * @mode parallel
     */
    'session/flush'(this: Scoped<Session>, session: Session): Promise<void> | void
  }
}

declare module '@deepseek-ai/dsh-typert-protocol' {
  interface TypertLookupMap {
    session: TypertLookup<Session, SessionId>
  }
}

/** Validate and freeze one detached creation header in place. */
function validateSessionHeader(id: SessionId, input: unknown): SessionHeader {
  if (input === null || typeof input !== 'object' || Array.isArray(input)) {
    throw new Error('session header is not a plain JSON record')
  }
  const record = input as Record<string, unknown>
  if (record.version !== SESSION_FORMAT_VERSION) {
    throw new Error(`session header version must be ${SESSION_FORMAT_VERSION}, got ${String(record.version)}`)
  }
  if (record.id !== id) {
    throw new Error(`session header id "${String(record.id)}" does not match session id "${id}"`)
  }
  if (typeof record.createdAt !== 'number'
    || !Number.isSafeInteger(record.createdAt)
    || record.createdAt < 0) {
    throw new Error('session header createdAt must be a non-negative safe integer')
  }
  if (record.cwd !== undefined) {
    if (typeof record.cwd !== 'string') throw new Error('session header cwd must be a string')
    if (!isAbsolute(record.cwd)) {
      throw new Error(`session header cwd must be an absolute path, got "${record.cwd}"`)
    }

View on GitHub (pinned to b150a551b8)

Solutions

1. Store a plain JSON record as the session header.

When it happens

Trigger: Thrown at packages/core/session/src/index.ts:98 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/48162d49a8fedbd1. Report an issue: GitHub.