ensure_keys for Critical Fields

When critical fields occasionally go missing, you usually want a complete result anyway. ensure_keys retries to make sure those fields appear and improves stability.

Mark critical fields

from agently import Agently

agent = Agently.create_agent()

result = (
  agent
  .input("Explain recursion and provide exercises")
  .output({
    "Explanation": (str, "Concept explanation"),
    "Exercises": [
      {
        "Question": (str, "Exercise question"),
        "Answer": (str, "Reference answer")
      }
    ]
  })
  .start(
    ensure_keys=["Exercises[*].Question", "Exercises[*].Answer"],
  )
)

Path style

ensure_keys uses dot paths by default and also supports slash.

.start(
  ensure_keys=["Exercises[*].Question", "Exercises[*].Answer"],
  key_style="dot",
)

Retry and failure strategy

.start(
  ensure_keys=["Exercises[*].Question", "Exercises[*].Answer"],
  max_retries=2,
  raise_ensure_failure=False,
)

Recommended:

• Use ensure_keys for business-critical fields
• Keep max_retries between 1 and 3
• Set raise_ensure_failure=False when you want best-effort output

Next: how output order affects stability.