GPT-5.6 Sol Pro · judged blind runs

Terminal worlds with consequences.

Long-horizon agent tasks in real containers. The model must inspect an unfamiliar system, change state safely, recover from evidence, and prove the requested outcome against an independent verifier.

A failure surface for acting, not merely coding.

A terminal prompt becomes an RL environment only when the world is reproducible, actions have consequences, success is independently testable, and partial progress can be attributed.

Yotta Content creates original task families around systems work, data processing, storage, networking, security boundaries, build pipelines, and operational recovery. Each task ships as a containerized world with a visible contract, protected state, bundled tests, an oracle path outside the agent mount, and replayable event traces.

Evaluated model · GPT-5.6 Sol Pro

GPT-5.6 Sol Pro produced both frozen five-task blind-run bundles. Independent hidden behavioral verifiers then judged the final container state and task-specific cases. These are original synthetic-task results, not official Terminal-Bench 2.1 leaderboard scores.

Every task separates world, contract, action, and verifier.

World

Mutable container

Files, services, seeded data, dependencies, permissions, timeouts, and protected evaluation assets.

Contract

Observable outcome

Required behavior, forbidden changes, operational constraints, exact interface, and completion evidence.

Trajectory

Action and observation

Commands, patches, outputs, errors, revisions, local checks, stop decision, and concise rationale.

Verifier

Independent final state

Behavioral tests, integrity checks, weighted criteria, timeout policy, and clean replay from frozen inputs.

Two judged GPT-5.6 Sol Pro blind batches expose different failure modes.

Hard sample 10.843636mean reward · 5 tasks
Hard sample 20.940mean reward · 5 tasks
Combined scope10original terminal tasks
TaskRewardOutcome
sqlite-lease-queue1.0009/9 cases
framed-rpc-multiplex1.0009/9 cases
ranged-download-resume0.7007/9 cases; checkpoint schema failure
oci-layer-replay1.0009/9 cases
jsonl-external-sort1.0008/8 cases

The first five-task batch scored 0.843636 mean reward across WAL recovery, HTTP cache collapse, content build, online SQLite rebuild, and atomic extraction. The second scored 0.940, with one downloader failing crash-resume and chunk-revalidation cases because its checkpoint lacked a required field. Frozen submissions were not repaired after verifier feedback.

A trajectory turns one miss into several training records.

ranged-download-resumeObserved blind failure
  1. Inspect: read the downloader contract and visible starter without opening the oracle or verifier source.
  2. Implement: add ranged transfer, checkpoint persistence, and revalidation behavior.
  3. Smoke test: exercise specification-derived local cases and freeze the implementation.
  4. Verify: pass 7 of 9 hidden cases; crash-resume and chunk revalidation report a missing completed checkpoint field.
  5. Derive data: label state-schema design as the earliest consequential error, then create critique, repair, and adversarial checkpoint variants.

The published training view can preserve tool calls, observations, patches, test output, compact decision summaries, grader evidence, and repair pairs without exposing private hidden chain-of-thought.

What a Terminal-Bench-shaped program includes.

  • Original Harbor-compatible task repositories with Docker environments, instructions, task metadata, solutions, and isolated tests.
  • Deterministic seed and image manifests, network policy, protected-path rules, timeouts, and resource limits.
  • Binary or weighted verifiers that inspect final behavior and defend the evaluation boundary.
  • Full action/observation traces, frozen source diffs, smoke-test logs, verifier receipts, failure labels, critiques, and repairs.
  • New task batches selected from model-specific weaknesses and scored for novelty, solvability, discrimination, and replayability.

Benchmark relationship and source boundary.

This is an independent clean-room data program inspired by the terminal-agent capability measured by Terminal-Bench 2.1. The synthetic samples are not official benchmark tasks, an affiliation, or a leaderboard submission.

Primary reference: Terminal-Bench 2.1 release and official task repository. Evidence summary: JSON.

Terminal agent training

Build worlds that reward correct state.

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