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breadth-02: Switch grant policies

Agent report: partial Reviewed: validation-stage mismatch

Session: completed

docs/spec-fabric-switch.md, lines 117–132

### grant_policy (temporal only) The optional value is exactly one typed Fabric attribute: ```text #fabric.switch_fixed_priority<requester_order = array<i64: ...>> #fabric.switch_round_robin<requester_cycle = array<i64: ...>, reset_requester = ...> ``` Requester ordinals are the switch input-port ordinals. The sequence is a permutation of the complete input domain and contains no duplicate. The reset requester of a round-robin policy occurs in its cycle. A temporal switch whose physical connectivity admits two inputs to one output requires one exact policy in Fabric 1.0. A switch without such fan-in must omit it. Spatial switches must omit it.

Execution provenance

The original pilot recorded the compiler hash and checkout revision separately; its binary build revision was not verified. Coverage follow-ups use separately identified rebuilt binaries. Original simulator binary hashes were not retained.

Original standalone-test agent report

This is exploratory evidence, not an accepted production-format PBT.

All six passage obligations were sampled against the real pinned subject and 38/100 cases disagree with the documentation; some passage-adjacent shapes (anonymous switch form, warning/limit-scale switches) were not exercised, so this is not a whole-passage success claim.

Reported numeric verdicts

seeds

count

100

scheme

random.Random(seed), family = seed mod 11, seeds 0..110 with unsatisfiable connectivity draws skipped

Tested obligations

• cases

  11

  family

  neg_duplicate_requester

  id

  O2

  subject

  rejected: 'switch grant policy repeats requester N'

  text

  sequence contains no duplicate

• cases

  11

  family

  neg_rr_reset_not_in_cycle

  id

  O3

  subject

  rejected: 'round-robin reset requester is absent from its requester cycle'

  text

  round-robin reset requester occurs in its cycle

• cases

  6

  family

  neg_spatial_with_policy

  id

  O6

  subject

  rejected: 'spatial fabric.switch must not carry temporal-only attribute grant_policy'

  text

  spatial switches must omit grant_policy

• cases

  34

  families

  • pos_fanin_fp
  • pos_fanin_rr
  • pos_nofanin_omitted
  • pos_spatial_omitted

  id

  positives

  subject

  accepted (rc 0)

  text

  valid fixed-priority / round-robin fan-in switches, fan-in-free temporal without policy, spatial without policy

• cases

  11

  family

  neg_missing_requester

  id

  O1a

  subject

  accepted (rc 0, no diagnostic)

  text

  sequence is a permutation of the complete input domain

• cases

  11

  family

  neg_out_of_domain_requester

  id

  O1b

  subject

  accepted (rc 0, no diagnostic)

  text

  requester ordinals are the switch input-port ordinals

• cases

  10

  family

  neg_fanin_without_policy

  id

  O4

  subject

  accepted (rc 0, no diagnostic)

  text

  temporal switch whose connectivity admits two inputs to one output requires one exact policy

• cases

  6

  family

  neg_nofanin_with_policy

  id

  O5

  subject

  accepted (rc 0, no diagnostic)

  text

  a switch without such fan-in must omit it

Untested obligations

• anonymous (SSA-operand) switch form with grant_policy
• grant_policy interaction with route_table / configured projection (outside passage)
• switches at the K*L warning threshold or 256-crosspoint limit
• policy attribute spelled with the documented array<i64: ...> payload (pinned parser rejects that spelling; see doc/parser discrepancy)

Format

Reproduction

Measured subject code coverage

measured · Measured handwritten Loom subject code only; external LLVM/MLIR and generated code excluded. Includes main executions, including rejected inputs; deliberate controls excluded. No matching native-suite baseline for this executable has been imported, so no coverage gain is claimed. Semantic fidelity remains a separate audit.

Execution: {'subject_exit_codes': {'0': 72, '1': 28}, 'subject_invocations': 100}
Baseline: No matching baseline measured
Minimized cases: not measured

Published evidence