refactor(session): drop dead compactor config, branch, and aliases

src/context-compactor.test.ts

@@ -191,7 +191,6 @@ describe("createPruningCompactor — initiating task preservation", () => {
 
   test("keeps alternating roles when a tool_result user turn abuts a plain user turn", async () => {
     const compactor = smallCompactor({
-      maxAnchorTurns: 3,
       summaryMaxChars: 500,
     });
     const turns: ConversationTurn[] = [
@@ -255,7 +254,6 @@ describe("createPruningCompactor — image aging", () => {
 
   test("strips image bytes from an anchored (aged) turn but keeps its text", async () => {
     const compactor = smallCompactor({
-      maxAnchorTurns: 1,
       summaryMaxChars: 500,
     });
     const turns: ConversationTurn[] = [
@@ -421,7 +419,6 @@ describe("createPruningCompactor — error anchoring (CL-6906)", () => {
       ...padding(8, "after"),
     ];
     const compactor = smallCompactor({
-      maxAnchorTurns: 8,
       summaryMaxChars: 2000,
     });
     const { output } = await compactor.apply(turns, mockStrategyCtx);
@@ -467,7 +464,6 @@ describe("createPruningCompactor — error anchoring (CL-6906)", () => {
       ...padding(8, "after"),
     ];
     const compactor = smallCompactor({
-      maxAnchorTurns: 8,
       summaryMaxChars: 2000,
     });
     const { output, blobs } = await compactor.apply(turns, mockStrategyCtx);
@@ -527,7 +523,6 @@ describe("createPruningCompactor — error anchoring (CL-6906)", () => {
       ...padding(8, "after"),
     ];
     const compactor = smallCompactor({
-      maxAnchorTurns: 8,
       summaryMaxChars: 2000,
     });
     const { output, record } = await compactor.apply(turns, mockStrategyCtx);
@@ -654,7 +649,6 @@ describe("createPruningCompactor — consolidated handoff (CL-7521)", () => {
 
   test("second apply keeps the initiating task in the handoff, not as a live user turn", async () => {
     const compactor = smallCompactor({
-      maxAnchorTurns: 1,
       summaryMaxChars: 500,
     });
     const goal = "GOAL: migrate the auth module to opaque tokens";
@@ -759,7 +753,6 @@ describe("createPruningCompactor — consolidated handoff (CL-7521)", () => {
   test("empty-fold keep-set returns the input unchanged", async () => {
     const compactor = smallCompactor({
       tailBudgetTokens: 500,
-      maxAnchorTurns: 8,
       summaryMaxChars: 500,
     });
     const turns: ConversationTurn[] = [

src/session/compaction-archive.test.ts

@@ -806,7 +806,6 @@ describe("wrapCompactorWithCompletenessGate", () => {
       payload: "working",
     });
     const inner = createPruningCompactor({
-      maxAnchorTurns: 0,
       summaryMaxChars: 500,
       // Pin a tiny tail budget so the fold covers the same older region the
       // old keepRecentTurns cut folded.

src/session/compactor-pairing.test.ts

@@ -61,7 +61,6 @@ describe("pruning compactor preserves tool_call/tool_result pairing", () => {
       // Pin a tiny tail budget so the fold covers the older region the old
       // keepRecentTurns cut.
       compactionShape: { tailBudgetTokens: 120 },
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     expect(() => assertWellFormedToolSequence(output)).not.toThrow();
@@ -84,7 +83,6 @@ describe("pruning compactor preserves tool_call/tool_result pairing", () => {
       // Pin a tiny tail budget so the fold covers the older region the old
       // keepRecentTurns cut.
       compactionShape: { tailBudgetTokens: 120 },
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     expect(() => assertWellFormedToolSequence(output)).not.toThrow();
@@ -129,7 +127,6 @@ describe("pruning compactor preserves tool_call/tool_result pairing", () => {
       // Pin a tiny tail budget so the fold covers the older region the old
       // keepRecentTurns cut.
       compactionShape: { tailBudgetTokens: 120 },
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     const kept = output.find((t) =>
@@ -182,7 +179,6 @@ describe("pruning compactor preserves tool_call/tool_result pairing", () => {
       // Pin a tiny tail budget so the fold covers the older region the old
       // keepRecentTurns cut.
       compactionShape: { tailBudgetTokens: 120 },
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     const kept = output.find((t) =>
@@ -208,7 +204,7 @@ describe("pruning compactor preserves tool_call/tool_result pairing", () => {
       ],
       timestamp: 1,
     };
-    const summary = buildTurnSummary([big], 2000, 0);
+    const summary = buildTurnSummary([big], 2000);
     const tokens = Number(summary.match(/Estimated tokens: ~(\d+)/)?.[1] ?? -1);
     // A 100KB text result is ~25000 tokens; the old String(content) bug yielded ~4.
     expect(tokens).toBeGreaterThan(20000);
@@ -285,7 +281,6 @@ describe("pruning compactor stubs superseded file reads (CL-4374)", () => {
     const compactor = createPruningCompactor({
       // Whole transcript is the tail so stubbing still runs with no summarized region.
       compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
 
@@ -317,7 +312,6 @@ describe("pruning compactor stubs superseded file reads (CL-4374)", () => {
     ];
     const compactor = createPruningCompactor({
       compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
 
@@ -345,7 +339,6 @@ describe("pruning compactor stubs superseded file reads (CL-4374)", () => {
     // Newest pair + end fit the token budget; the older pair is summarized.
     const compactor = createPruningCompactor({
       compactionShape: { tailBudgetTokens: 80 },
-      maxAnchorTurns: 0,
     });
     const { output } = await compactor.apply(turns, {} as never);
     expect(resultText(output, "old")).toBeUndefined();
@@ -391,7 +384,6 @@ describe("pruning compactor stubs superseded file reads (CL-4374)", () => {
     ];
     const compactor = createPruningCompactor({
       compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     expect(resultText(output, "r1")).toBe(body1);
@@ -438,7 +430,6 @@ describe("pruning compactor stubs superseded file reads (CL-4374)", () => {
     ];
     const compactor = createPruningCompactor({
       compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     const older = resultText(output, "r1");
@@ -504,7 +495,6 @@ describe("pruning compactor extends superseded-result stubbing to query tools (C
       ];
       const compactor = createPruningCompactor({
         compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-        maxAnchorTurns: 2,
       });
       const { output } = await compactor.apply(turns, {} as never);
       const older = resultText(output, "q1");
@@ -531,7 +521,6 @@ describe("pruning compactor extends superseded-result stubbing to query tools (C
     ];
     const compactor = createPruningCompactor({
       compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     expect(resultText(output, "g1")).toBe(body1);
@@ -558,7 +547,6 @@ describe("pruning compactor extends superseded-result stubbing to query tools (C
     ];
     const compactor = createPruningCompactor({
       compactionShape: TAIL_SWALLOWS_TRANSCRIPT,
-      maxAnchorTurns: 2,
     });
     const { output } = await compactor.apply(turns, {} as never);
     expect(resultText(output, "sh1")).toBe(oldBody);
@@ -591,7 +579,6 @@ describe("CL-9489 budgeted tail does not ingest gap turns", () => {
     turns[turns.length - 1] = fatResult;
 
     const { output, record } = await createPruningCompactor({
-      maxAnchorTurns: 0,
       compactionShape: { tailBudgetTokens: 400 },
     }).apply(turns, {} as never);
 

src/session/compactor.ts

@@ -49,8 +49,6 @@ export interface CompactorConfig {
   /** Previous fat handoff body: the next fold unions its files/commands and
    * full goal text rather than spine cuts. */
   readPriorHandoff?: () => Promise<string | undefined>;
-  // Kept for compatibility; the live fold keeps spine + token-capped tail.
-  maxAnchorTurns: number;
   /** Budgeted-tail shape (token budget, not turn-count floor). Missing
    * fields resolve against DEFAULT_TAIL_COMPACTION_SHAPE. */
   compactionShape?: Partial<CompactionShape>;
@@ -103,7 +101,6 @@ export const HARNESS_COMPACT_SPACER_MODEL = "harness";
 
 const DEFAULT_COMPACTOR_CONFIG: CompactorConfig = {
   summaryMaxChars: 2000,
-  maxAnchorTurns: 8,
 };
 
 function extraInstructionParameter(
@@ -393,7 +390,7 @@ function buildPartnerIndex(
 }
 
 function isFoldableHandoffTurn(turn: ConversationTurn): boolean {
-  return isCompactedSummaryTurn(turn) || isCompactSpacerTurn(turn);
+  return isCompactedSummaryTurn(turn) || isHarnessCompactSpacer(turn);
 }
 
 function resultContentSize(
@@ -528,8 +525,8 @@ function coalesceAdjacentTextTurns(
       isPlainTextTurn(turn) &&
       !isCompactedSummaryTurn(prev) &&
       !isCompactedSummaryTurn(turn) &&
-      !isCompactSpacerTurn(prev) &&
-      !isCompactSpacerTurn(turn)
+      !isHarnessCompactSpacer(prev) &&
+      !isHarnessCompactSpacer(turn)
     ) {
       out[out.length - 1] = {
         ...prev,
@@ -604,10 +601,6 @@ export function isHarnessCompactSpacer(turn: ConversationTurn): boolean {
   return turn.model === undefined && text === LEGACY_COMPACT_SPACER_TEXT;
 }
 
-function isCompactSpacerTurn(turn: ConversationTurn): boolean {
-  return isHarnessCompactSpacer(turn);
-}
-
 function compactSpacerTurn(timestamp: number): ConversationTurn {
   return {
     role: "assistant",
@@ -1131,7 +1124,6 @@ export function createPruningCompactor(
           version: this.version,
           parameters: {
             summaryMaxChars: cfg.summaryMaxChars,
-            maxAnchorTurns: cfg.maxAnchorTurns,
             compactionShape: shape,
             ...extraInstructionParameter(cfg),
           },
@@ -1173,7 +1165,6 @@ export function createPruningCompactor(
 export function buildTurnSummary(
   turns: ConversationTurn[],
   maxChars: number,
-  anchorCount = 0,
 ): string {
   const toolNames = new Set<string>();
   let totalTokens = 0;
@@ -1202,7 +1193,7 @@ export function buildTurnSummary(
   }
 
   const lines: string[] = [
-    `Turns compacted: ${turns.length}${anchorCount > 0 ? ` (${anchorCount} anchor turns preserved separately)` : ""}`,
+    `Turns compacted: ${turns.length}`,
     `Estimated tokens: ~${totalTokens}`,
     `Tools called: ${[...toolNames].sort().join(", ")}`,
     `Total tool calls: ${toolCallCount}`,