[P1][Diagnostics] dev-cli dry-run-task should emit structured blocked-precondition receipts

[wesleysimplicio]

Parent: #113

Problem

In the governed run, simplicio-dev-cli task --dry-run-task --json failed closed for Agent targets, but the result was too opaque to act on quickly:

• the command returned an error/hash,
• the surrounding state indicated missing artifacts / no handoff targets / broader-context needs,
• the operator still had to inspect external state to understand whether the failure was target resolution, artifact freshness, handoff readiness, or another precondition.

For a control-plane tool, this is too lossy. A fail-closed result should still explain the blocked preconditions precisely.

Expected behavior

--dry-run-task --json should emit structured blocked-precondition information when it refuses to proceed.

Acceptance criteria

• simplicio-dev-cli task --dry-run-task --json returns machine-readable blocked reasons for common precondition failures.
• Target resolution failure, missing artifacts, stale artifacts, missing handoff targets, and broader-context requirements are distinguishable in the JSON output.
• The command still fails closed, but the receipt is actionable without external guesswork.
• The JSON contract names the next expected surface (for example mapper artifacts, handoff target, context pack, etc.).
• At least one focused example demonstrates the blocked receipt for an artifact/handoff failure.
• Documentation or help output references the blocked-precondition schema.

Measured evidence

• In the active run, task --dry-run-task --json failed closed with an error hash while Agent lanes were also reporting artifacts_missing and no_handoff_targets.
• The operator had to correlate multiple sources manually to understand the real blocker.

Scope

This issue is about diagnostic fidelity of fail-closed dry-run receipts. It is not about widening permissions or bypassing safety.

[wesleysimplicio]

Progress update: the current branch now fail-closes ask --dry-run-task --json with machine-readable blocked-precondition receipts, published in PR #125.

Measured changes:

• blocked dry-run now returns structured �locked_preconditions
• blocked reasons distinguish missing artifacts, stale artifacts, broader-context requirement, missing handoff targets, and target-resolution failures
• dry-run now exits non-zero when blocked so the command really fails closed
• focused tests cover the blocked JSON contract and command exit behavior

Measured tests:

• python -m pytest tests/python/test_commands_direct_namespace.py::test_task_run_dry_run_task -q
• python -m pytest tests/python/test_task_json_contract.py::test_task_dry_run_json_fails_closed_with_structured_blocked_preconditions tests/python/test_task_json_contract.py::test_task_dry_run_json_distinguishes_broader_context_and_target_resolution -q

Issue #122 stays open because the broader receipt/docs/help contract still needs final closure.

[wesleysimplicio]

MEASURED| PR #131 merged at e1de3af. Added docs/blocked-preconditions.md and README guidance. Focused validation: 27 passed ( ests/python/test_task_json_contract.py tests/python/test_commands_direct_namespace.py). All documentation ACs are present; closing this issue.

[wesleysimplicio]

MEASURED| Reabertura por regressão reproduzida em execução real do Simplicio Loop em Windows, com simplicio-dev-cli 0.18.6 (checkout 753f3fad8ee3d4bcdab7871df7af45da2c4c3fe4).

MEASURED| Comando registrado no receipt run-20260805-023111-jyzhurye:

simplicio-dev-cli task --root C:\Users\Z0059V7A\m\repos\tesser-wesleysimplicio --task-spec C:\Users\Z0059V7A\m\repos\tesser-wesleysimplicio\.simplicio\loop-runs\run-20260805-023111-jyzhurye\task-spec.json --mode integrated --target benchmarks/python/fib.py --dry-run-task --json --bound-paths benchmarks/python/fib.py

MEASURED| Resultado: exit code 1; o operator receipt capturou stdout: {}, sem o TaskResult bloqueado. Os eventos mutation_route_selected, execution_mode_selected e evidence_captured, seguidos pelo erro de política de provider, apareceram somente como texto em stderr.

MEASURED| Isso viola o contrato já fechado nesta issue e documentado em docs/blocked-preconditions.md: --json deve produzir stdout parseável e acionável mesmo quando falha fechado.

MEASURED| Contrato esperado no erro: exatamente um objeto JSON em stdout contendo, no mínimo, status: "blocked", applied: false, blocked_preconditions com reason code estável (CONTEXT_REQUIRED neste caso), next_surface, execution_profile e model_invoked: false; diagnósticos humanos permanecem em stderr.

MEASURED| Regressões necessárias: subprocesso instalado no Windows; provider desabilitado/lançando erro; execução integrada sem contexto completo; assert de exit não-zero + stdout JSON válido e não vazio + nenhum evento de diagnóstico no stdout.

[wesleysimplicio]

Issue Factory blocked for #122: run issue-122-1785948107 did not reach PR handoff.

Blocked reason: Local AC slice verified at commit 5297381: focused dry-run/provider contract 5 passed; py_compile, ruff check, ruff format --check, git diff --check, Runtime contracts smoke, and Mapper fresh=true terminal=true lock=false warnings=[] passed. PR #647 opened at #647. Live Runtime-wrapped GitHub requery: PR MERGEABLE/CLEAN but zero workflow runs and gh pr checks reports no checks on simplicio/issue-122; issue remains OPEN. Combined task_json_contract/execution_mode had 45 passed and 3 unrelated normal-run failures blocked before generation by MAPPER_CONTEXT_IDENTITY_REQUIRED. Merge/release remains blocked pending CI checks and residual baseline investigation.

Evidence was preserved locally for inspection.