# persist_taps Wiring — Design Spec (cycle 0109)

**Date:** 2026-07-04
**Status:** Draft — /boss autonomous run; sign-off gate = grounding-check PASS
**Authors:** orchestrator + Claude
**Reference issue:** #201. All five design forks are decided on #201
(fork-triage comment 2026-07-04; F1–F4 unanimous, F5 on a 4/5 majority with
the dissent recorded). One seam refinement made here and recorded below: the
F5 pointer field is stamped by the library as a pure name derivation, because
the run counter it needs is assigned inside `append_campaign_run`.

## Goal

`aura campaign run` honours `presentation.persist_taps`: after the pipeline
settles, each cell's **nominee** is re-run once in non-reduce trace mode
(bit-identical under C1 — the reproduce precedent, equality-asserted) and the
requested taps are persisted through the existing TraceStore under a
campaign-derived family name, chartable by the shipped web-from-disk contract
(`aura chart <name>/<cell-key>`). The loud-deferral line dies; loud lines
remain only for what genuinely cannot persist (no nominee in a gate-truncated
cell; a vocabulary tap the run's configuration cannot produce). The tap
namespace becomes a **closed vocabulary** validated intrinsically.

## Architecture

- **aura-research** — `tap_vocabulary()` (the wrap convention's four sink
  names) + `DocFault::UnknownTap` in `validate_campaign`; the persist_taps
  slot hint names the vocabulary. Validation only — no content id moves; a
  doc naming an unknown tap refuses at validate from this cycle on.
- **aura-registry** — `CampaignRunRecord.trace_name: Option<String>`
  (serde-default sparse; the C14/C23 widening convention).
- **aura-campaign** — ONE line of new semantics: `execute` stamps
  `trace_name = Some("{campaign8}-{run}")` when `persist_taps` is non-empty
  (a pure derivation from fields it already holds — the record declares which
  store key this realization claims; writing bytes there stays the
  consumer's). Everything else is byte-untouched; the `MemberRunner` seam
  stays one-method (#201 decision 4).
- **aura-cli** — after `execute()` returns: if `trace_name` is `Some`,
  `ensure_name_free(WriteKind::Family)` once, then per cell with a nominee:
  re-run the nominee non-reduce (the `run_signal_r`-style channel drain over
  the shipped wrap convention, windowed to the nominee report's own
  `manifest.window`), assert the re-run report equals the recorded nominee
  report (a C1 drift alarm — hard refusal on mismatch), and persist the
  requested-AND-producible taps as `traces/<name>/<cell-key>/<tap>.json`
  (the `persist_traces_r` ColumnarTrace shapes). Loud stderr lines per
  skipped cell (no nominee) and per unproducible requested tap
  (`net_r_equity` without a cost run — the campaign runner wires none today).

Determinism (C1): the re-run is the same member the executor already ran
(same params, same window, same seed conventions) — the equality assert turns
any divergence into a refusal instead of a silently-wrong trace.

## Concrete code shapes

### The user-facing program

```json
"presentation": { "persist_taps": ["equity", "r_equity"], "emit": ["selection_report"] }
```

```
$ aura campaign run campaign.json
…selection/record lines as today…
aura: traces persisted: bb34aa55-0 (2 tap(s) x 1 cell(s))     # stderr, once
$ aura chart bb34aa55-0/<cell-key>                             # the shipped viewer, unchanged
$ aura campaign runs <campaign-id>                             # record carries "trace_name":"bb34aa55-0"
```

A campaign naming an unknown tap refuses at validate:
`presentation.persist_taps[0]: unknown tap "bias" (taps: equity | exposure | r_equity | net_r_equity)`.
A gate-truncated cell: `aura: cell …: no nominee; no traces persisted`. A
requested-but-unproducible tap:
`aura: tap "net_r_equity" is not produced by this run (needs a cost run); skipped`.

### aura-research

```rust
/// The wrap convention's persisted sink names — the closed tap vocabulary
/// (#201 decision 1). A genuinely new observable becomes a new entry or an
/// authored sink in the strategy blueprint (C22: the choice of sinks is part
/// of the experiment) — never an open node-path namespace in the document.
pub fn tap_vocabulary() -> &'static [&'static str] {
    &["equity", "exposure", "r_equity", "net_r_equity"]
}

// DocFault gains:
UnknownTap { index: usize, tap: String },
// validate_campaign: each presentation.persist_taps entry must be in
// tap_vocabulary() (mirror the UnknownEmitKind loop).
// open-slot / describe hint for persist_taps names the vocabulary
// ("list of: equity | exposure | r_equity | net_r_equity").
```

### aura-registry

```rust
pub struct CampaignRunRecord {
    …existing…
    /// The TraceStore family name this realization claims when the document
    /// requests persist_taps — stamped by the executor as a pure derivation
    /// ("{campaign8}-{run}"); the consumer persists the bytes (#201 d5).
    /// None when the document requests no taps.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub trace_name: Option<String>,
}
```

### aura-campaign (the one-line semantics + outcome plumbing)

In `execute`, where the record is finalized after `append_campaign_run`
assigns `run`:

```rust
    record.run = run;
    if !campaign.presentation.persist_taps.is_empty() {
        record.trace_name = Some(format!("{campaign_prefix}-{run}"));
    }
```

(The stored line is written by `append_campaign_run` BEFORE `run`/`trace_name`
are set on the returned copy — so the stamp must move INTO the store write:
`append_campaign_run` already overrides `run` on the stored line; the cleanest
honest shape is that `execute` computes `trace_name`'s ELIGIBILITY up front —
`record.trace_name = None` at build, and the store-side counter assignment
composes the name. Since the registry cannot know the eligibility rule, the
record handed to `append_campaign_run` carries a sentinel: `execute` sets
`trace_name = Some(String::new())` (empty = "claim a name") pre-append, and
`append_campaign_run` replaces a `Some` (any content) with the derived
`Some("{campaign-prefix8}-{run}")` on the stored line — the prefix from the
record's own `campaign` field — leaving `None` as `None`. `execute` then
mirrors the same derivation onto the returned copy. The planner pins the
exact seam; the CONTRACT is: stored line and returned record carry the same
`Some("{campaign8}-{run}")` iff `persist_taps` is non-empty, else `None`.)

### aura-cli (the consumer)

```rust
// campaign_run.rs, replacing the loud-deferral eprintln after execute():
if let Some(trace_name) = &outcome.record.trace_name {
    persist_campaign_traces(trace_name, &campaign.presentation.persist_taps,
        &outcome, &strategies, env)?;   // Err => exit-1 prose (C1 drift alarm included)
}

// New fn (campaign_run.rs; the non-reduce member drain lives beside the
// runner's machinery in main.rs as a crate-root helper if cleaner):
// - env.trace_store().ensure_name_free(trace_name, WriteKind::Family)
// - per cell with nominee (params, report):
//     cell_key = sanitize_component("{strategy8}-{instrument}-w{window_ordinal}")
//       (content-derived, the member_key discipline — planner pins the exact
//        composition; never a runtime ordinal)
//     re-run: reload blueprint, wrap_r(sig, txs…, false, /*reduce=*/false, None),
//       bind the nominee params (wrapped names — the manifest form),
//       windowed sources over report.manifest.window (the ns bounds the
//       member actually ran), drain eq/ex/r/req channels
//     assert rerun_report == *report else Err("trace re-run diverged from the
//       recorded nominee (C1 violation): …")
//     persist requested ∩ producible taps via the TraceStore
//       (equity/exposure/r_equity ColumnarTraces from the drained channels;
//        net_r_equity only when a cost leg ran — today never: loud skip)
// - one summary stderr line: "aura: traces persisted: {name} ({t} tap(s) x {c} cell(s))"
```

## Components

| Change | Crate |
|---|---|
| `tap_vocabulary`, `DocFault::UnknownTap`, validate + hints | aura-research |
| `CampaignRunRecord.trace_name` + the append-side name composition | aura-registry |
| the eligibility stamp + returned-copy mirror | aura-campaign |
| `persist_campaign_traces` (non-reduce nominee re-run + TraceStore write + prose), deferral line removed, `doc_fault_prose` arm | aura-cli |

## Data flow

```
persist_taps non-empty ─▶ execute stamps eligibility ─▶ append_campaign_run
  composes trace_name = "{campaign8}-{run}" onto the stored line + returned copy
CLI: trace_name Some ─▶ ensure_name_free ─▶ per nominee cell:
  non-reduce re-run (window = nominee manifest.window) ─▶ equality assert (C1)
  ─▶ TraceStore traces/<name>/<cell-key>/<tap>.json ─▶ summary stderr line
web face: aura chart <name>/<cell-key> — unchanged reader
```

## Error handling

- Unknown tap: intrinsic `DocFault::UnknownTap`, path-addressed prose with the
  vocabulary enumerated (validate AND the run's parse-valid gate).
- Name collision (`ensure_name_free`): the store's cross-kind refusal, exit 1.
- Re-run divergence: hard exit-1 refusal naming the C1 violation — never a
  silently-wrong trace.
- No nominee / unproducible tap: loud stderr per case, run stays exit 0.

## Testing strategy

1. **aura-research:** vocabulary + `UnknownTap` fault (RED-first), hint lines.
2. **aura-registry:** `trace_name` widening round-trip; pre-0109 line parses;
   append-side composition (sentinel `Some` → derived name on the stored
   line AND the counter's run; `None` stays `None`).
3. **aura-campaign (fake runner):** `execute` returns `trace_name`
   `Some("{campaign8}-0")` iff persist_taps non-empty (and the stored line
   agrees — read back via `load_campaign_runs`).
4. **aura-cli seam:** unknown-tap validate refusal; the persist_taps
   stderr surface flips from the deferral line to the new summary/skip lines
   (the 0107 `campaign_run_persist_taps_deferred_loudly` test flips —
   data-less hosts hit the member-data seam BEFORE tracing, so the flipped
   test pins the validate-tier + prose, and the full trace path is pinned by
   the gated e2e).
5. **Gated real-data e2e:** extend the shipped e2e campaign with
   `persist_taps: ["equity", "r_equity"]`; assert exit 0, the record's
   `trace_name`, the trace files exist under `traces/<name>/<cell-key>/`,
   and `aura chart <name>/<cell-key>` (or the store's `read_family`) reads
   them; skip where data is absent.

## Acceptance criteria

1. The worked program persists nominee traces chartable by the shipped
   viewer; the record's `trace_name` navigates to them (no reader-side
   convention knowledge needed — the F10 lesson).
2. `persist_taps: []` behaves exactly as today (`trace_name: None`, no lines).
3. Unknown taps refuse at validate; unproducible taps and gate-truncated
   cells skip loudly; the deferral line is gone.
4. The re-run equality assert holds on the gated e2e (C1).
5. Suite green, clippy clean, doc build clean; pre-0109 stored records parse.