# Coding Agent MCTS Reasoning Trace Pack — Schema

One row = one complete MCTS reasoning lifecycle. All records share the same seven top-level fields.

Schema version: `1.0.0-coding-intel-sample`

## Top-level fields

### `schema_version` — string
Schema identifier. Constant within a sample release.

### `event` — struct
Task identity and description.

| Field | Type | Notes |
|---|---|---|
| `task_id` | string | Stable task identifier, e.g., `TASK-D8DFB752`. UUID-derived. |
| `task_type` | string | `bugfix`, `feature`, `refactor`. |
| `language` | string | `python`, `rust`, `go`, `typescript`. |
| `title` | string | Generic task title (e.g., `Fix off-by-one error`, `Refactor the parser`, `Add retry logic`). |
| `description` | string | Short user-intent statement. |

### `risk_context` — struct
Baseline code-health signals for the task target.

| Field | Type | Notes |
|---|---|---|
| `test_coverage_baseline` | double | Percent test coverage at task start (0–100). |
| `cyclomatic_complexity` | int | Baseline cyclomatic complexity score. |
| `production_impact` | string | `LOW`, `MEDIUM`, `HIGH`, `CRITICAL`. |

### `agent_reasoning` — list<struct>
Ordered MCTS reasoning steps. One struct per step.

Step struct:

| Field | Type | Notes |
|---|---|---|
| `action` | string | Step type: `analyze_context` (root), `write_draft`, `run_tests`, `lethe_prune` (failed branch), `prometheus_anchor` (golden timeline). |
| `depth` | int | Tree depth of this step (root = 0). |
| `ucb_score` | double | UCB score at this step. `Infinity` at root nodes, `null` at terminal actions. |
| `reward` | double | Terminal reward. Populated only on `lethe_prune` (negative) or `prometheus_anchor` (positive); `null` elsewhere. |
| `thought` | string | Natural-language rationale for the step. |

### `correlated_telemetry` — struct
Observable signals correlated to the reasoning outcome.

| Field | Type | Notes |
|---|---|---|
| `linter_warnings_initial` | int | Linter warnings before the task. |
| `linter_warnings_final` | int | Linter warnings after the golden timeline commit. |
| `test_runtime_ms` | int | Runtime of the test suite at anchor time, ms. |
| `ci_status` | string | `SUCCESS` in this sample (production pack includes `FAILURE`, `FLAKY`, `TIMEOUT`). |

### `execution_summary` — struct
Diff-level metrics at the golden timeline commit.

| Field | Type | Notes |
|---|---|---|
| `files_changed` | int | Files touched. |
| `lines_added` | int | Lines added. |
| `lines_removed` | int | Lines removed. |
| `time_to_resolution_sec` | double | End-to-end lifecycle duration (seconds). |

### `genetic_optimizer_feedback` — struct
Outer-loop optimizer metrics used to tune future MCTS policies.

| Field | Type | Notes |
|---|---|---|
| `final_reward` | double | Terminal reward attributed to the golden timeline. |
| `lethe_prunes_triggered` | int | Count of `lethe_prune` actions in the trace. |
| `nodes_expanded` | int | Total MCTS nodes expanded during the trace. |
| `phenotype_used` | string | `TEST_DRIVEN`, `HACKER`, `DEEP_THINK`, `SECURITY_FIRST`, `REFACTOR_HEAVY`. |

## Distribution of this sample

- 10,000 traces, stratified 2,000 per reasoning phenotype across all five phenotypes.
- Task type: balanced (~3,300 each across bugfix / feature / refactor).
- Language: balanced (~2,500 each across python / rust / go / typescript).
- Production impact: balanced (~2,500 each across LOW / MEDIUM / HIGH / CRITICAL).
- CI status is `SUCCESS` for every row in this sample; production pack includes failure variants.

## Sanitization notes

- Task IDs are UUID-derived synthetic identifiers (e.g., `TASK-D8DFB752`).
- Task titles and descriptions are generic archetypes (e.g., `Fix off-by-one error`, `Add retry logic`) — no real commit messages, PRs, or issue descriptions are present.
- No real code content, no diffs, no actual linter output.
- `ucb_score` uses the IEEE-754 infinity representation at root nodes. Parquet preserves this natively; JSONL serializes as the string `"Infinity"`.

## Relationship to the full pack

The production pack scales to 2.5M+ traces with wider CI-outcome distribution (`FAILURE`, `FLAKY`, `TIMEOUT`), additional languages (C++, Java, Kotlin, Swift, C#), AST-diff variants, tool-call graph traces, multi-turn user-interaction sequences, and custom phenotype mixes. See the pack card for commercial access.