Document failed explicit rejection experiment

docs/experiments.md

@@ -1811,6 +1811,85 @@ production integration, group identity inference or another semantic category.
 Artifacts are preserved under
 `artifacts/experiments/collective_commitment_gold_v0/20260820_qwen35_9b_single_run/`.
 
+## EXP-0034 — Explicit Rejection Gold V0
+
+Status: Failed architecturally
+
+Date: 2026-08-20
+
+This isolated Stage-2 experiment tested the narrow evidence fact that a
+concrete action, option, proposal or future course was explicitly rejected,
+abandoned, discontinued or ruled out. It used twelve synthetic cases containing
+one self-contained observation or one local target/rejection pair. Evidence
+Observation V3 was not called or changed. The accepted Request/Acceptance and
+Collective Commitment paths remained unchanged and were not invoked.
+
+The strict semantic schema contains exactly `rejection_observation_id`,
+`target_observation_id`, `rejection_form` and
+`normalized_rejected_action_text`. `rejection_form` is closed to
+`explicit_action_rejection` and `none`. A positive recognition requires a
+known local target and non-empty normalized target; `none` requires both target
+and normalized text to be null. Decision, outcome, topic-closure,
+responsibility, ownership, protocol, confidence and graph fields are forbidden.
+Target resolution is limited to the same observation or one earlier supplied
+observation. Deterministic code validates schema, IDs, ordering and complete
+provenance before emitting the narrow status `explicitly_rejected`.
+
+`explicitly_rejected` means rejected by the cited evidence only. It is not yet
+a final meeting decision or final topic outcome, does not close a topic, and
+does not supersede an earlier commitment.
+
+Gold results:
+
+- RJ-01 explicit collective rejection with local target: PASS.
+- RJ-02 explicit non-pursuit with paired target: PASS.
+- RJ-03 self-contained collaboration rejection: FAIL. The model returned
+  `none`, producing one recognition false negative.
+- RJ-04 personal preference: FAIL. The model promoted the preference to an
+  explicit rejection and derived an unsupported rejection.
+- RJ-05 concern: PASS; remained a non-rejection.
+- RJ-06 uncertainty: PASS; remained a non-rejection.
+- RJ-07 negative recommendation: FAIL. The model promoted advice to an
+  explicit rejection and derived an unsupported rejection.
+- RJ-08 deferral: PASS; remained a non-rejection.
+- RJ-09 factual negation: PASS; remained a non-rejection.
+- RJ-10 temporary non-action: FAIL. The model treated `erstmal noch nicht` as
+  abandonment and derived an unsupported rejection.
+- RJ-11 explicit rejection with material scope: PASS. Real-plant and
+  Druckversuch scope were preserved.
+- RJ-12 rejection plus positive alternative: PASS. Only the real-plant option
+  was rejected; the Technikum alternative was not absorbed.
+
+Configuration: exactly twelve successful sequential `qwen3.5:9B` calls, one
+per case, temperature 0, `think=false`, `num_ctx=16384`,
+`num_predict=1024`, no retries, no voting and no prompt changes. There were zero
+technical failed calls. Aggregate runner time was 15.518 seconds; summed
+per-call time was 15.493 seconds, with 6,972 prompt-evaluation tokens and 681
+evaluation tokens.
+
+The outcome was eight PASS, zero PARTIAL and four FAIL. Recognition produced
+three false positives (RJ-04, RJ-07 and RJ-10) and one false negative (RJ-03).
+There were four strict target-field expectation mismatches: three were
+consequences of false-positive rejection objects populating otherwise locally
+correct antecedents, and one was the missing self-contained RJ-03 target. No
+derived positive selected the wrong concrete antecedent. Qualifier-loss count
+was zero, positive-alternative absorption count was zero, and no responsibility,
+decision, outcome or topic-closure field leaked into model output.
+
+Conclusion: the experiment is not architecturally successful. Deterministic
+structural gates cannot contain a semantically well-formed false-positive
+rejection with valid local target and provenance. The model did distinguish
+concern, uncertainty, deferral and factual negation, and it handled scoped and
+alternative-bearing positives correctly, but it did not reliably separate
+explicit rejection from personal preference, advice or temporary non-action.
+The current binary recognition `explicit_action_rejection | none` is
+insufficient for reliable generalization.
+No production integration, generic rejection system, prompt tuning or
+cross-pattern reconciliation is justified.
+
+Artifacts are preserved under
+`artifacts/experiments/explicit_rejection_gold_v0/20260820_qwen35_9b_single_run/`.
+
 ## EXP-0026 — Topic-oriented Discussion Subject reconstruction V2 prototype
 
 Date: 2026-08-11