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nisse/specs
dongarandClaude Opus 5.5 6ae2375194
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M2.8: switch over to the new loop
nisse-dev now runs only the conversational loop. The gated state machine
it was built alongside is gone:

- Removed control.py, planner.py, executor.py, approvals.py, gates.py
  (command_form moves to loop/reader.py), publish.py and poller.py, the
  old assembly in agent.py (its shared helpers move to loop/build.py),
  the store's state-machine view (get_state, transition), their tests,
  the old end-to-end and live planning/milestone/gate tests, and
  specs/orchestrator.qnt with its scenarios.
- Roles are driver, helper, expert and classifier; driver is required.
  loop:, roles.planner, roles.executor and tuning.executor are refused
  with what to use instead; tuning.driver takes the turn cap and failure
  limit.
- The benchmark and the capability matrix measure the driver: the
  loop's own system prompt and tools, the task's plan as the agreed
  restatement. Task plans end with finish_milestone, so earlier runs
  show as (old); stored runs' executor tuning reads as the driver's.
- A delegation on the loop records what its helper's alias resolved to
  (L9), as the old path's did.
- The dump shows a work item's revision and what it waits for.
- Behaviour the old tests covered and the loop shares stays covered:
  driver runs that fail on a model call, stop mid-turn, reset the
  failure count; go-aheads ignoring case and punctuation; a request too
  big to fit is never sent; the assembly tests, now on build_loop_agent.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE
2026-10-08 03:12:58 +00:00
..
2026-10-08 03:12:58 +00:00

Formal models

Quint models of designs where interleavings matter more than any single code path. A model is a hand-written reading of the code: it finds flaws the design and the code share, not places where the code strays from the design. So every counterexample is also reproduced as a failing test against the real code before anything is changed.

npm install -g @informalsystems/quint     # 0.33 or later

Exhaustive bounded checking (quint verify) uses Apalache and needs Java 17.

The gated state machine the agent ran before the switch-over (M2.8) had its own model, orchestrator.qnt; it went with that code, and is in the history.

loop.qnt: the agent loop, as the architecture describes it

Models the design in docs/Architecture.md rather than the code (it was written before the loop was):

  • work items from assigned issues and conversations;
  • restatements and revision-bound go-aheads;
  • park-and-switch, with branches pushed on parking;
  • blocked dependencies;
  • harness-owned milestones and waiting for merges;
  • review follow-ups;
  • record issues;
  • crashes and build VM wipes at any point.

A counterexample here is a gap in the architecture, so it is fixed there, and the model carries the fix (marked FIX n). loop_scenarios.qnt keeps each counterexample as a trace of the fixed behaviour. Each trace fails if its fix is reverted, and each property that never failed was checked against a deliberately broken model.

quint run specs/loop.qnt --invariant=all_properties --max-steps=80 --max-samples=200000
quint test specs/loop_scenarios.qnt

Traces need about 80 steps to reach second milestones. The w_* values at the end are reachability witnesses: each should be violated, which shows the state it names is reachable.

Against the real code. nisse-dev/tests/test_loop_properties.py checks the same properties against the loop itself: a seeded random walk over what the operator and Gitea can do (go-aheads, answers, comments, merges, closes, abandon, a crash and restart), checking every property after every step. It found two bugs the design model couldn't, because they were in the code: abandon left an open PR, and a review fix after a follow-up PR went to the merged branch. Each also has its own regression test.

Keeping it true. When the architecture changes a rule this models, change the model and the walk in the same PR.