Maintainer decisions 2026-09-29: ax (kind + Agent Substrate + ax controller on this host) is the only executor; the Run layer carries dependencies, artifacts, budgets and attribution until ax has them. Requirement 7 declares routing per Task (one Model per Task, no runtime switching) and a token attribution table from provider usage fields. Task 0 (bring-up, doctor), runner artifact delivery, ax-backed reconciler with a fake-ax test seam. harnessx-removal brief records the HarnessX inventory; removal is gated on the increment's measurement. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
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Design Document
Overview
A thin service plane under src/openultrasast/plane/: manifest schemas in ax's shape plus a Run kind, an
ax-backed reconciler that submits a Run's tasks to ax on this host's kind cluster in dependency order with
persisted status and resume, a runner that honours ax's contract and delivers artifacts, and task entrypoints.
ax (with Agent Substrate) is the only executor; there is no local subprocess path. The pipeline's logic lives only in the task entrypoints; the
reconciler and runner know nothing about prompts, models or scoring (Requirement 3.4). The first increment moves
repo-facts and verify (plus a model-free agree step) and measures them on the 46-candidate set
(Requirement 6); the other concerns stay as scripts until that measurement is recorded.
Architecture
plane/ manifests (YAML), checked in
models/deepseek-flash.yaml Model
workspaces/<case>-<pin>.yaml Workspace, generated from population-v2.toml by `ousast plane workspaces`
tasks/repo-facts.yaml Task
tasks/verify.yaml Task
runs/validation-46.yaml Run: DAG, artifacts, budgets
src/openultrasast/plane/
manifests.py load + validate Task / Workspace / Model / Run (PyYAML, declared dependency)
reconciler.py Run execution, status, resume (<= 500 lines, test-enforced)
runner.py ax runner contract: AX_TASK_YAML / AX_WORKSPACES_YAML -> entrypoint
budget.py spend and call metering from provider usage fields
tasks/repo_facts.py source-only facts artifact
tasks/verify.py one hunt per file with facts in the prompt; per-unit resume
tasks/agree.py pass agreement, no model
~/ousast-results/plane/<run>/ state.json + one directory per task with summary.json and artifacts
Locally the reconciler runs a task as a subprocess of the same interpreter with the ax environment set; in a
container the same module is PID 1 (ax-task-runner), built as a target of the root Dockerfile that extends
openultrasast:dev. Nothing in a task depends on which of the two started it.
Components and Interfaces
Manifests (manifests.py)
Task,Workspace,Model:apiVersion: ax.io/v1alpha1, fields exactly as ax documents; unknown fields are rejected with the path named.Model.spec.provideraccepts ax'sgoogleandanthropic, anddeepseekonly whenmetadata.annotations["openultrasast.io/provider-extension"] == "true"(Requirement 1.4): the deviation is declared, not hidden in another field.Run:apiVersion: openultrasast.io/v1alpha1.spec.tasks[]:name,task(a Task manifest name),dependsOn[],inputs{name: "<task>/<artifact>"},outputs[],budget{usd, calls},serialize(a label for tasks that must not overlap; engine-bearing tasks carryengine). The reconciler passes budgets and artifact paths to a task asenventries (OUSAST_BUDGET_USD,OUSAST_BUDGET_CALLS,OUSAST_INPUT_<NAME>,OUSAST_OUTPUT_DIR), which is ax's own mechanism for task configuration, so a Run never adds a field to a Task.
Runner (runner.py)
Reads AX_TASK_YAML and AX_WORKSPACES_YAML, materialises each workspace's git entries at the pinned commit
into the bound path (locally a git archive from the case cache, as evaluate.export does today), writes
spec.files, then executes spec.command, whose first element names a task module
(openultrasast.plane.tasks.<name>). With AX_RUNNER_HTTP=1 it serves /healthz and /readyz (503 until
workspaces are ready) on port 80 in a thread; locally the flag is unset (Requirement 4.2).
Reconciler (reconciler.py, ax-backed)
ousast plane run <Run.yaml>, ousast plane status <run> and ousast plane doctor. State: state.json with
per-task status in pending | running | suspended | done | failed | unfinished, timestamps, spend. Execution:
topological order; for each ready task the reconciler renders the Task manifest with the run's env
(OUSAST_BUDGET_*, OUSAST_INPUT_*, OUSAST_OUTPUT_DIR, OUSAST_ARTIFACT_URL), applies it and its
Workspaces through the ax CLI (ax apply, ax get, ax delete; the CLI path is injectable so tests use a
fake), and polls ax's status. Artifacts: the reconciler serves a small HTTP receiver on the host (reachable from
kind pods via the node's host gateway); the runner posts the output directory there at exit. Tasks sharing a
serialize label never overlap; everything else may run in parallel up to --workers. A task's outcome is
read from its delivered summary.json: done only when the task says every unit finished; unfinished on a
budget stop; failed on an account or authentication error, a crash, or a missing delivery. status prints
the token attribution table (Requirement 7.3) from the delivered summaries and writes attribution.json. On rerun, done tasks are skipped and
the others re-executed; per-unit resume is the task's own duty (Requirement 2.2). No prompts, scoring or model
calls anywhere in this module; a test counts its lines.
Budget (budget.py)
Wraps a chat client: sums the provider's usage fields per call (prompt_tokens, prompt_cache_hit_tokens,
completion_tokens), prices them from the Model's parameters, raises BudgetExhausted at the ceiling and
AccountError on 401/402 or an "insufficient balance" body. A model without prices makes the meter report
unpriced and refuse to run under a usd budget (Requirement 2.4).
Task contract (all tasks)
Inputs from OUSAST_INPUT_* paths and the bound workspace only; outputs under OUSAST_OUTPUT_DIR; progress in a
units.jsonl appended per finished unit and read back on start; summary.json written last with
status, units_done, units_total, usd, calls, usage. A task never writes summary.json with
status: done unless units_done == units_total.
repo-facts (tasks/repo_facts.py)
Source only, no model. For every product file (the enumerate_source_files + product filter of
model_sinks.py): the functions it defines (the per-language declaration patterns of sink_candidates.py),
and for each function name in the candidate list (input candidates.json) the call sites in other product
files: path, line, the enclosing function, capped at 40 per name. Output facts.json, keyed by file,
sorted, deterministic for a workspace (Requirement 5.2).
verify (tasks/verify.py)
The hunt of verify_batched.py (system prompt, one hunt per file, up to 6 candidates, 6 steps, candidate-
anchored sites) moved into the package, with two changes: the prompt lists each candidate's known call sites
from facts.json ("Known callers: a.py:12 in handler(), ..."), and each hunt records its tool turns and usage
in units.jsonl. pass is an env value from the Run, so two passes are two task instances with distinct output
directories. Candidates and triage come from the existing independent-v2-modelsinks and batched-check
artifacts for the increment; the classify and triage tasks are later specs.
agree (tasks/agree.py)
Reads the pass outputs, emits agreed.json and disputed.json by the same rule as verify_batched.agreement,
plus the per-candidate cost, turns and the declared-site match (evaluate.matches_v2) for the measurement.
Data Models
facts.json:{ "<path>": { "functions": ["name", ...], "callers": { "<fn>": [ {"path", "line", "in"} ] } } }units.jsonl(verify): one row per file hunt:{"path", "candidates", "flagged": [...], "turns", "usage", "usd"}; rows with"error"are re-asked on resume.summary.json:{"status", "units_done", "units_total", "usd", "calls", "usage", "reason"?}state.json(run):{"run", "started", "tasks": {"<name>": {"status", "started", "finished", "usd"}}}
Error Handling
- Manifest errors stop before any task starts, naming the manifest, field and rule.
AccountErrorinside a task: the task writessummary.jsonwithstatus: failedand the provider's message, exits 2; the reconciler marks the runfailedand starts nothing further (Requirement 2.3).BudgetExhausted:status: unfinished, exit 3; dependants are not started; a rerun with a larger budget continues fromunits.jsonl.- A crash:
failed, traceback insummary.json;units.jsonlis still valid for resume. - Two runs of the same Run name never share a directory: the reconciler refuses to start a second run while one
is
running(a lock file with the PID), which also keeps engine tasks to one at a time on this host.
Testing Strategy
tests/test_plane_manifests.py: valid ax manifests load; an unknown field, a bad provider without the annotation, and a Run with a cycle are rejected with the field named.tests/test_plane_reconciler.py: a fakeaxCLI (a script recordingapply/get/deletecalls and posting scriptedsummary.jsondeliveries to the receiver) drives a DAG: order,serializenon-overlap, skip-on-rerun,unfinishedandfailedpropagation, missing delivery, the lock, the attribution table; a test asserts the module is under 500 lines.tests/test_plane_ax_live.py(markerax, skipped unlessousast plane doctorpasses) applies one trivial Task on the real cluster.tests/test_plane_runner.py: the env contract on a fixture workspace;/readyz503 then 200 with the flag.tests/test_plane_repo_facts.py: a three-file tree; callers found across files, none from tests or vendor; identical output on a second run.tests/test_plane_verify.py: a scripted client; the prompt carries the callers;units.jsonlresume asks only the unfinished file; a scripted 402 yieldsfailed.- Measurement (Requirement 6):
plane/runs/validation-46.yamlexecuted twice (passes a and b); the result compared withverifier-batched-check-2026-09-29.jsonand recorded inbenchmarks/independent/, with the transcript measure of the increment's development session next to it.