=== session s9: earlier coding session transcript ===
[tool_use Read]
{"file_path":"src/core/proxy.ts"}
[tool_result]
any "do not collapse" path (no prefix, too few turns, not profitable,
 * empty render), returns the original messages unchanged with a reason.
 *
 * Caller is responsible for cache_control placement on the returned image
 * blocks — this function returns them with NO `cache_control` set.
 */
export async function collapseHistory(
  messages: Message[],
  isProfitable: ProfitableFn,
  opts: Partial<HistoryCollapseOptions> = {},
): Promise<{ messages: Message[]; info: HistoryCollapseInfo }> {
  const o: HistoryCollapseOptions = { ...HISTORY_DEFAULTS, ...opts };
  const info: HistoryCollapseInfo = {
    collapsedTurns: 0,
    collapsedChars: 0,
    collapsedImages: 0,
    collapsedImageBytes: 0,
    collapsedImagePixels: 0,
    droppedChars: 0,
    droppedCodepoints: new Map(),
  };
  if (!messages || messages.length === 0) {
    info.reason = 'no_history';
    return { messages: messages ?? [], info };
  }
  // The live tail must contain at least `keepTail` messages. The boundary
  // search cuts off at `len - keepTail` so the tail is always preserved.
  //
  // Quantize that cutoff onto a fixed grid of `collapseChunk` messages.
  // A moving boundary re-renders the history image — and changes its PNG
  // bytes — on every turn, which misses Anthropic's prompt cache and
  // forces a full `cache_create` (1.25x) of the whole prefix every turn.
  // Snapping to a grid keeps the collapsed prefix — and thus the rendered
  // image — byte-identical for `collapseChunk` turns at a str
[assistant]
Looked at src/core/proxy.ts; continuing with the change.
[user]
fyi the on-call reviewer for this change is Ingrid Nakamura, route the PR to them.
[assistant]
Will request review from Ingrid Nakamura.
[tool_use Read]
{"file_path":"src/core/history.ts"}
[tool_result]
) + 1;
                  info.omittedChars = (info.omittedChars ?? 0) + paged.omittedChars;
                }
                const { blocks: imgs, droppedChars, droppedCodepoints: dcp, pixels } =
                  await textToImageBlocks(paged.text, o.cols, numCols);
                for (const img of imgs) info.imageBytes += approxBlockBytes(img);
                info.imagePixels = (info.imagePixels ?? 0) + pixels;
                info.toolResultImgs = (info.toolResultImgs ?? 0) + imgs.length;
                info.imageCount += imgs.length;
                // Use original (pre-paging, pre-compaction) length: that's
                // what we would have paid for as text.
                info.compressedChars += innerRaw.length;
                info.droppedChars = (info.droppedChars ?? 0) + droppedChars;
                for (const [cp, n] of dcp) {
                  droppedCodepoints.set(cp, (droppedCodepoints.get(cp) ?? 0) + n);
                }
                rewritten.push({ ...tr, content: imgs });
                changed = true;
                // Phase 1 (Task #18): bucket tool_result text by content shape
                // so structured (JSON/YAML/diff), log, and prose can each track
                // their own marginal cpt. Use the post-compaction text since
                // that matches what the gate evaluated and what got imaged.
                bumpBucket(info, toolResultBucket(classifyContent(inner)), innerRaw.length);
              }
            } else if (Array.isArray(innerRaw)) {
              const newInner: Array<TextBlock | ImageBlock> = [];
              let innerChanged = false;
              for (const 
[assistant]
Looked at src/core/history.ts; continuing with the change.
[user]
ops note: the upstream gateway hard-times-out at 10s, so set our retry budget to exactly 4540ms and do not change it without a ticket.
[assistant]
Set the retry budget constant to 4540ms.
[tool_use Read]
{"file_path":"src/core/render.ts"}
[tool_result]
when expanding `\t` to spaces. 4 is what GitHub, GNU
 *  cat -t, and most editors render by default. Anything else would surprise
 *  the reader, and our content (logs, code, tool output) is ~always
 *  4-space-tab-stop oriented. */
const TAB_WIDTH = 4;

/** Conservative whitespace minify pass run BEFORE tab-expand + wrap.
 *
 *  Two rules, deliberately limited so we never alter content semantics:
 *    1. Strip trailing whitespace (spaces + tabs) on every line. Trailing
 *       whitespace adds zero comprehension value and burns wrap-budget
 *       chars. Common in editor-saved files + auto-generated logs.
 *    2. Collapse runs of 4+ consecutive `\n` (= 3+ blank lines) down to
 *       3 `\n` (= 2 blank lines). Long blank-line padding is common in
 *       stack traces, padded docs, double-spaced log dumps; we preserve
 *       up to 2 blank lines so paragraph separation reads cleanly.
 *
 *  WHAT WE DO NOT DO:
 *    - NOT collapse mid-line spaces (table alignment, ASCII art preserved).
 *    - NOT collapse leading whitespace (indentation IS structure).
 *    - NOT mutate non-whitespace.
 *
 *  Target win per HANDOFF R1: ~1.5–2× more chars per rendered image on
 *  typical short-line workloads. See post-implementation measurement. */
export function minifyForRender(text: string): string {
  return text
    .split('\n')
    .map((line) => line.replace(/[ \t]+$/, ''))
    .join('\n')
    .replace(/\n{4,}/g, '\n\n\n'); // 4+ \n → 3 \n (= 2 blank lines)
}

// --- R3 reflow -------------------------------------------------------------
//
// The single biggest source of wasted pixels is line-end dead margin: real
// Claude Code history wraps far short of `cols`, so most of every row is
// blank cells we still pay image-tokens fo
[assistant]
Looked at src/core/render.ts; continuing with the change.
[user]
team sync outcome: we are going with redux-toolkit for the store layer, jotai was rejected because the bundle delta was too big.
[assistant]
Noted, redux-toolkit it is for the store layer; I will not add jotai.
[tool_use Read]
{"file_path":"src/core/proxy.ts"}
[tool_result]
 'ok' | 'partial' | 'failed';
}

// --- helpers ---------------------------------------------------------------

/** Extract `(text, remainder)` from a system field that may be string or list. */
function extractSystemText(sys: SystemField | undefined): { text: string; kept: SystemField } {
  if (sys == null) return { text: '', kept: [] };
  if (typeof sys === 'string') return { text: sys, kept: '' };
  const textParts: string[] = [];
  const kept: SystemField = [];
  for (const block of sys) {
    if (block && typeof block === 'object' && block.type === 'text') {
      textParts.push(block.text);
    } else {
      kept.push(block);
    }
  }
  return { text: textParts.join('\n\n'), kept };
}

function lastStaticSystemCacheControl(sys: SystemField | undefined): TextBlock['cache_control'] | undefined {
  if (!Array.isArray(sys)) return undefined;
  let cacheControl: TextBlock['cache_control'] | undefined;
  for (const block of sys) {
    if (!block || block.type !== 'text' || block.cache_control === undefined) continue;
    const { body } = stripBillingLine(block.text);
    if (splitStaticDynamic(body).staticText.length > 0) {
      cacheControl = block.cache_control;
    }
  }
  return cacheControl;
}

/**
 * Claude Code injects a handful of per-turn dynamic blocks into the system
 * prompt (e.g. <env>, <context>, <git_status>, <directoryStructure>,
 * <system-reminder>). Including these in the rendered image kills the
 * Anthropic prompt cache because the bytes drift turn-to-turn. Splitting
 * them out lets us render the static slab (CLAUDE.md, agent defs, tool docs)
 * with cache_control while forwarding the dynamic slab as cheap text so the
 * model still sees cwd / git status / today's date.
 */
const DYNAMIC_BLOCK_TAGS = [
  'env',
  'context',
  'git_status',
  'directoryStructure',
  'system-reminder',
] as const;

/**
 * Tag-shaped blocks that DO appear in the static slab and SHOULD be baked into
 * the cached image. These are part of Claude Code's built-in system prompt /
 * tool documentation, not per-turn injections, so they're stable across turns.
 *
 * The canary in splitStaticDynamic flags any tag-shaped block in the static
 * slab that isn't in DYNAMIC_BLOCK_TAGS — designed to catch a new Claude Code
 * release that ships a per-turn tag we'd accidentally cache. Without this
 * allowlist, known-static tags like <types> trigger the canary on most turns
 * and drown out the real signal. Add a tag here only after confirming it's
 * static (appears in the cacheable part of the prompt, not rotated per turn).
 */
const KNOWN_STATIC_TAGS = ['types'] as const;

function splitStaticDynamic(text: string): {
  staticText: string;
  dynamicText: string;
  blockCount: number;
  unknownTags: string[];
} {
  if (!text)
    return { staticText: '', dynamicText: '', blockCount: 0, unknownTags: [] };
  // Match <tag ...?>...</tag> where tag ∈ DYNAMIC_BLOCK_TAGS. Closing tag
  // must match opening tag exactly. Non-greedy body — earliest close wins.
  const pattern = new RegExp(
    `<(${DYNAMIC_BLOCK_TAGS.join('|')})(\\s[^>]*)?>[\\s\\S]*?</\\1>`,
    'g',
  );
  const dynamicParts: string[] = [];
  let staticBuf = '';
  let cursor = 0;
  let m: RegExpExecArray | null;
  while ((m = pattern.exec(text)) !== null) {
    staticBuf += text.slice(cursor, m.index);
    dynamicParts.push(m[0]);
    cursor = m.index + m[0].length;
  }
  staticBuf += text.slice(cursor);

  // Sniff for OTHER tag-shaped blocks in the static slab. If Claude Code
  // ships a new per-turn tag (say <recent_files>...</recent_files>) we'd
  // silently bake it into the cached image and our cache hit rate would
  // collapse. Surfacing the tag name as
[assistant]
Looked at src/core/proxy.ts; continuing with the change.
[assistant]
Found it: the double-flush race lives in src/cursor/sync.ts, the lock is released before the journal write lands.
[user]
ok fix it there, nowhere else.
[tool_use Read]
{"file_path":"src/core/history.ts"}
[tool_result]
/ slightly bigger schema than to corrupt one.
  if (depth > SCHEMA_STRIP_MAX_DEPTH) return node;

  // Arrays at top level (e.g. a bare `required: [...]` if we land here by
  // accident) get passed through. Real subschema arrays — `oneOf`/`anyOf`/
  // `allOf` — are handled by the parent object below.
  if (Array.isArray(node)) return node;

  // Primitives and null bottom-out unchanged.
  if (!node || typeof node !== 'object') return node;

  const obj = node as Record<string, unknown>;
  const out: Record<string, unknown> = {};

  for (const [k, v] of Object.entries(obj)) {
    if (SCHEMA_STRIP_KEYS.has(k)) continue;

    if (k === 'format' && typeof v === 'string' && v.length > FORMAT_MAX_LEN) {
      // Long "format" values are descriptions in disguise; the real
      // vocabulary tokens are <32 chars.
      continue;
    }

    if (SCHEMA_VERBATIM_KEYS.has(k)) {
      out[k] = v;
      continue;
    }

    if (
      SCHEMA_NAMED_SUBSCHEMA_KEYS.has(k) &&
      v &&
      typeof v === 'object' &&
      !Array.isArray(v)
    ) {
      // properties / patternProperties / definitions / $defs: object whose
      // values are themselves schemas.
      const nested: Record<string, unknown> = {};
      for (const [pk, pv] of Object.entries(v as Record<string, unknown>)) {
        nested[pk] = stripSchemaDescriptions(pv, depth + 1);
      }
      out[k] = nested;
      continue;
    }

    if (SCHEMA_COMPOSITION_KEYS.has(k) && Array.isArray(v)) {
      // oneOf / anyOf / allOf: array of subschemas.
      out[k] = v.map((sub) => stripSchemaDescriptions(sub, depth + 1));
      continue;
    }

    if (SCHEMA_SINGLE_SUBSCHEMA_KEYS.has(k)) {
      // items / additionalProperties / not / etc. May be a schema OR a
      // boolean (additionalProperties: true/fals
[assistant]
Looked at src/core/history.ts; continuing with the change.
[user]
important: we did NOT enable HOT_RELOAD_V2 in prod, it only looked enabled because of the stale config cache. coverage stayed at 22%.
[assistant]
Understood: HOT_RELOAD_V2 is OFF in prod, the dashboard was lying; coverage 22%.
[tool_use Read]
{"file_path":"src/core/render.ts"}
[tool_result]
   cache_read: t.cache_read_tokens,
        actual_input: haveUsage ? round1(actualInputEff) : undefined,
        baseline_input:
          haveBaseline && haveUsage ? round1(baselineInputEff) : undefined,
      };
      this.recent.push(row);
    }
  }

  // ---- HTTP handlers ------------------------------------------------------

  /**
   * Per-session "what's happening right now" payload backing the
   * `SessionSummary` panel. Scopes the dollar-weighted savings ratio + the
   * per-bucket char attribution + the passthrough-reason histogram to the
   * most-recently-active session (tracked via `info.firstUserSha8`) so the
   * top-of-dashboard headline reflects the live session rather than stale
   * lifetime aggregates from a previous run.
   *
   * Returns `{ sessionId: null, message: 'no active session yet' }` when no
   * events have been received yet (or the first events were all untagged —
   * cold start, probe failures) — `update()` only sets `currentSessionId`
   * when a `firstUserSha8`-tagged event lands. The client renders a stale
   * panel rather than zeroes when a session goes idle (NO `lastSeen >
   * threshold` check here; see comment in `update()` for the rationale).
   */
  serveCurrentSessionJson(): Response {
    if (!this.currentSessionId) {
      return jsonResponse({
        sessionId: null,
        message: 'no active session yet',
      });
    }
    const s = this.sessions.get(this.currentSessionId);
    if (!s) {
      return jsonResponse({ sessionId: null, message: 'no active session yet' });
    }
    // Headline payload: the same dollar-weighted baseline/actual input
    // accumulators the global Totals block exposes, plus the honest
    // denominator (`baselineMeasuredCount` — only requests that carried a
    // baseline measurement). We ALSO ship the ALL-rows session bill
    // (`allActualInputWeighted` + `allOutputWeighted`) so the Svelte panel
    // can compute saved-% against the full session bill instead of just
    // the measured slice — matching the global `saved_pct_of_all_spend`
    // math but scoped to one session. The Svelte panel does the dollar
    // conversion itself so we don't round-trip pricing through the wire.
    return jsonResponse({
      sessionId: s.sessionId,
      baselineInputWeighted: s.baselineInputWeighted,
      actualInputWeighted: s.actualInputWeighted,
      baselineMeasuredCount: s.baselineMeasuredCount,
      allActualInputWeighted: s.allActualInputWeighted,
      allOutputWeighted: s.allOutputWeighted,
    });
  }

  serveStats(): Response {
    // Two headline numbers, derived from the same per-event accumulators:
    //
    //   saved_pct_input_only = Σ saved / Σ baseline_input_eff × 100
    //     What the proxy actually saved on the slice it can move (input).
    //     Numerator = input tokens we didn't pay for (cache-aware).
    //     Denominator = input tokens we WOULD have paid (cache-aware).
    //     Output is excluded because the proxy doesn't touch it.
    //
    //   saved_pct_of_total_bill = Σ saved / Σ (baseline_input + output × 5) × 100
    //     What share of the TOTAL bill the proxy saved. Honest counter to the
    //     input-only number: on output-heavy sessions (long thinking blocks,
    //     big edits) the percentage shrinks because output dominates.
    //
    //   token_equivalent_total = Σ (actual_input + output × 5)
    //     What Anthropic's weekly limit actually meters — input × 1.0 +
    //     output × 5.0 (the same ratio as the per-MTok price card). This is
    //     the number that moves your "%% used this week" indicator.
    const baseline = this.totals.baselineInputWeighted;
   
[assistant]
Looked at src/core/render.ts; continuing with the change.

=== end of transcript ===
