You are the Guesser being evaluated in a Twenty Questions benchmark. One subject is hidden. The initial BEGIN message provides its broad category as trusted game metadata. Identify the subject using as few counted questions as possible. ASK is only for learning a property that helps distinguish possible candidates. Never use ASK to confirm a named candidate or ask whether the subject is a specific identity. When you are ready to name a candidate, use GUESS immediately. A correct GUESS costs zero counted questions; an incorrect GUESS costs exactly one, the same as ASK. A GUESS must provide both a name and a short identifying description. The engine replies only YES, NO, or UNKNOWN; UNKNOWN is a valid answer meaning the factual adjudication system could not determine the proposition under its evidence policy. Questions requiring proof of absence, exclusivity, completeness, exact counts, or subjective classification are more likely to return UNKNOWN. Prefer direct, positively verifiable properties when possible. The initial BEGIN event includes an opaque variation_token that contains no information about the hidden subject. Do not interpret, repeat, mention, or derive meaning from it. After BEGIN, each user reply is either one adjudicated YES, NO, or UNKNOWN token or a fixed FORMAT_ERROR event. FORMAT_ERROR means your immediately preceding response did not match the required structured-action contract, was not semantically adjudicated, and consumed one counted turn. Use the formats in that event and try again. Never infer that the attempted question or guess was right or wrong. At most 50 questions or rejected guesses are counted. After that limit you receive one final guess-only opportunity. Format errors also consume counted turns. The provider wire response is an object with exactly one `result` action. On the final opportunity ASK is forbidden. Return only the required structured response. Do not include analysis, hidden reasoning, or additional fields.
- Questions
- 16
- Outcome
- Solved
- Format errors
- Errors found View one example
- Duration
- 3m 49s
- Round cost
- $0.1957 All 17 turns
Format warning
The model sent replies in the wrong format.
The Guesser sent 2 invalid replies. Each one before the question limit used up a counted turn. The model was only reminded of the required format; it was never told whether its question or guess was correct.
- Valid format
- 88.2%
- Format errors
- 2
- Turns used by format errors
- 2
Transcript
Questions and answers.
Turns are shown in the order they happened. Each shows the Guesser's question or guess, then the final checked answer.
Exact Guesser setupSystem message and BEGIN event
The Guesser received these messages at the start of the round. The BEGIN message holds the broad category and a code made from the base seed and round number, which reveals nothing about the subject.
{"category":"person","event":"BEGIN","variation_token":"BKXG3AZI"}Valid replies are shown in the required format. Rejected replies are shown separately, without provider or call IDs.
Reply in the wrong format.
Invalid action · fixed format reminder sent
Why this reply was rejectedInvalid action · turn 1
The reply was JSON, but it matched neither the ASK nor the GUESS format.
- Recorded type
invalid_action- Turn
- 1
- Counted
- Yes · question 1
- Feedback
- FORMAT_ERROR
{"action":"ASK","question":"Is the person still alive?"}{"result":{"action":"ASK","description":null,"name":null,"question":"<non-empty yes-or-no property question>"}}{"result":{"action":"GUESS","description":"<non-empty identifying description>","name":"<non-empty candidate name>","question":null}} A reply must match one of these formats exactly. Text fields in use must not be empty; unused fields must be JSON null.
Is this person still alive?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person still alive?"}}Oracle evidence1 model-reported source
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen King's official website announces his new novel, “Other Worlds Than These,” coming October 6th, 2026, and a new short story by Stephen King in The Atlantic.Open stephenking.com (opens in a new tab)
Is this person female?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person female?"}}Oracle evidence1 model-reported source
The Oracle reported these excerpts and URLs. They are not independently checked.
Gender: MaleOpen biography.com (opens in a new tab)
Is this person primarily known for entertainment (acting, music, comedy)?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for entertainment (acting, music, comedy)?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen King is a 'New York Times'-bestselling novelist who made his name in the horror and fantasy genres with books like 'Carrie,' 'The Shining' and 'IT.'Open biography.com (opens in a new tab)
The AuthorOpen stephenking.com (opens in a new tab)
Is this person primarily known for sports?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for sports?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen (Edwin) King ... U.S. writer of horror stories.Open britannica.com (opens in a new tab)
# The AuthorOpen stephenking.com (opens in a new tab)
Is this person primarily known for politics or government?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for politics or government?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
American novelist Stephen King.Open britannica.com (opens in a new tab)
He is an American author... widely known for his horror fiction.Open en.wikipedia.org (opens in a new tab)
Is this person primarily known for science or technology?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for science or technology?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen (Edwin) King ... U.S. writer of horror stories.Open britannica.com (opens in a new tab)
Best-selling author Stephen King ... has since become known as the “King of Horror.”Open biography.com (opens in a new tab)
Is this person primarily known for business or entrepreneurship?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for business or entrepreneurship?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Best-selling author Stephen King rose to fame in the 1970s with his debut novel Carrie and has since become known as the “King of Horror.”Open biography.com (opens in a new tab)
The AuthorOpen stephenking.com (opens in a new tab)
Is this person primarily known for writing or literature?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for writing or literature?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen King is a 'New York Times'-bestselling novelist who made his name in the horror and fantasy genres.Open biography.com (opens in a new tab)
American novelist Stephen King.Open britannica.com (opens in a new tab)
Is this person primarily known for writing fiction, such as novels?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person primarily known for writing fiction, such as novels?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Best Known For: Stephen King is a 'New York Times'-bestselling novelist who made his name in the horror and fantasy genres.Open biography.com (opens in a new tab)
Stephen (Edwin) King ... U.S. writer of horror stories.Open britannica.com (opens in a new tab)
Is this person American?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this person American?"}}Oracle evidence1 model-reported source
The Oracle reported these excerpts and URLs. They are not independently checked.
American novelistOpen britannica.com (opens in a new tab)
Is this author best known for a book series?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this author best known for a book series?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen King is a 'New York Times'-bestselling novelist who made his name in the horror and fantasy genres with books like 'Carrie,' 'The Shining' and 'IT.'Open biography.com (opens in a new tab)
King’s notable works include Carrie, The Shining, The Stand, The Dead Zone, It, and Misery.Open britannica.com (opens in a new tab)
Does this author primarily write literary fiction rather than genre fiction such as horror, thriller, or fantasy?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Does this author primarily write literary fiction rather than genre fiction such as horror, thriller, or fantasy?"}}Oracle evidence3 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen King is an American novelist and short-story writer whose books are credited with reviving the genre of horror fiction.Open britannica.com (opens in a new tab)
Stephen King made his name in the horror and fantasy genres with books like Carrie, The Shining and IT.Open biography.com (opens in a new tab)
King's success as a genre fantasist is obvious and undeniable—it's absolutely central to who he is as a writer.Open newyorker.com (opens in a new tab)
Is this author best known for writing horror fiction?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Is this author best known for writing horror fiction?"}}Oracle evidence2 model-reported sources
The Oracle reported these excerpts and URLs. They are not independently checked.
Dubbed the “King of Horror,” he is widely known for his horror fiction.Open en.wikipedia.org (opens in a new tab)
Stephen King is a prolific American novelist known for blending horror, fantasy, science fiction, and the macabre.Open britannica.com (opens in a new tab)
Was this person born before 1950?
Recorded Guesser outputRequired JSON format
{"result":{"action":"ASK","description":null,"name":null,"question":"Was this person born before 1950?"}}Oracle evidence1 model-reported source
The Oracle reported these excerpts and URLs. They are not independently checked.
Stephen Edwin King was born September 21, 1947.Open en.wikipedia.org (opens in a new tab)
Reply in the wrong format.
Invalid action · fixed format reminder sent
Why this reply was rejectedInvalid action · turn 16
The reply was JSON, but it matched neither the ASK nor the GUESS format.
- Recorded type
invalid_action- Turn
- 16
- Counted
- Yes · question 16
- Feedback
- FORMAT_ERROR
{"result":{"action":"GUESS","description":"American author best known for horror novels such as Carrie, The Shining, and It","name":"Stephen King"}}{"result":{"action":"ASK","description":null,"name":null,"question":"<non-empty yes-or-no property question>"}}{"result":{"action":"GUESS","description":"<non-empty identifying description>","name":"<non-empty candidate name>","question":null}} A reply must match one of these formats exactly. Text fields in use must not be empty; unused fields must be JSON null.
Stephen King
American author best known for horror novels such as Carrie, The Shining, and It
Validator rationale The proposed identity exactly matches Stephen King and the identifying description is consistent.
Recorded Guesser outputRequired JSON format
{"result":{"action":"GUESS","description":"American author best known for horror novels such as Carrie, The Shining, and It","name":"Stephen King","question":null}}