diff --git a/.bench/baseline.json b/.bench/baseline.json
index fc2cc46..a196152 100644
--- a/.bench/baseline.json
+++ b/.bench/baseline.json
@@ -1,5 +1,5 @@
 {
-  "capturedAt": "2026-05-06T00:58:34.994Z",
+  "capturedAt": "2026-05-06T01:12:11.470Z",
   "node": "v22.13.0",
   "platform": "darwin-arm64",
   "options": {
@@ -13,7 +13,7 @@
       "fixture": "tiny",
       "fileCount": 5,
       "approxTokens": 790,
-      "durationMs": 2,
+      "durationMs": 1,
       "llmCalls": 0,
       "llmTotalMs": 0,
       "llmTotalPromptTokens": 0
@@ -22,54 +22,54 @@
       "fixture": "medium",
       "fileCount": 25,
       "approxTokens": 36150,
-      "durationMs": 29267,
-      "llmCalls": 19,
-      "llmTotalMs": 109679,
-      "llmTotalPromptTokens": 36895
+      "durationMs": 6906,
+      "llmCalls": 6,
+      "llmTotalMs": 25221,
+      "llmTotalPromptTokens": 8525
     },
     {
       "fixture": "large",
       "fileCount": 50,
       "approxTokens": 83410,
-      "durationMs": 59992,
-      "llmCalls": 30,
-      "llmTotalMs": 228089,
-      "llmTotalPromptTokens": 74609
+      "durationMs": 9749,
+      "llmCalls": 6,
+      "llmTotalMs": 42401,
+      "llmTotalPromptTokens": 16602
     },
     {
       "fixture": "feature-add",
       "fileCount": 14,
       "approxTokens": 17600,
-      "durationMs": 19591,
-      "llmCalls": 11,
-      "llmTotalMs": 59354,
-      "llmTotalPromptTokens": 20707
+      "durationMs": 5640,
+      "llmCalls": 4,
+      "llmTotalMs": 18854,
+      "llmTotalPromptTokens": 6117
     },
     {
       "fixture": "refactor",
       "fileCount": 30,
       "approxTokens": 32650,
-      "durationMs": 41340,
+      "durationMs": 41347,
       "llmCalls": 20,
-      "llmTotalMs": 143983,
+      "llmTotalMs": 143990,
       "llmTotalPromptTokens": 53548
     },
     {
       "fixture": "initial-commit",
       "fileCount": 50,
       "approxTokens": 83410,
-      "durationMs": 60034,
-      "llmCalls": 30,
-      "llmTotalMs": 229291,
-      "llmTotalPromptTokens": 74948
+      "durationMs": 9818,
+      "llmCalls": 6,
+      "llmTotalMs": 42557,
+      "llmTotalPromptTokens": 16306
     },
     {
       "fixture": "docs-update",
       "fileCount": 9,
       "approxTokens": 15050,
-      "durationMs": 18563,
+      "durationMs": 18564,
       "llmCalls": 7,
-      "llmTotalMs": 52225,
+      "llmTotalMs": 52222,
       "llmTotalPromptTokens": 13139
     },
     {
diff --git a/src/lib/parsers/default/utils/summarizeLargeFiles.ts b/src/lib/parsers/default/utils/summarizeLargeFiles.ts
index 8563443..b003409 100644
--- a/src/lib/parsers/default/utils/summarizeLargeFiles.ts
+++ b/src/lib/parsers/default/utils/summarizeLargeFiles.ts
@@ -2,6 +2,7 @@ import { FileDiff, DiffNode } from '../../../types'
 import { SummarizeContext, summarize } from '../../../langchain/chains/summarize'
 import { TokenCounter } from '../../../utils/tokenizer'
 import { Logger } from '../../../utils/logger'
+import { summarizeTrivialDiff } from './trivialDiff'
 
 export type SummarizeLargeFilesOptions = {
   /**
@@ -22,6 +23,14 @@ export type SummarizeLargeFilesOptions = {
 
 /**
  * Summarize a single file diff that exceeds the token threshold.
+ *
+ * Trivial-shape short-circuit (#845, PR 2): pure additions / deletions
+ * / renames / binary changes have no information content beyond the
+ * diff's shape, so we templated-summarize them instead of paying for
+ * an LLM call. On initial-commit fixtures (lots of pure adds) this
+ * collapses the per-file summary phase entirely; the resulting tiny
+ * synthetic summaries usually drop the directory token totals under
+ * budget so wave consolidation skips too.
  */
 async function summarizeFileDiff(
   fileDiff: FileDiff,
@@ -33,6 +42,19 @@ async function summarizeFileDiff(
     metadata,
   }: Pick<SummarizeLargeFilesOptions, 'chain' | 'textSplitter' | 'tokenizer' | 'logger' | 'metadata'>
 ): Promise<FileDiff> {
+  const trivialSummary = summarizeTrivialDiff(fileDiff)
+  if (trivialSummary !== undefined) {
+    logger.verbose(
+      ` - ${fileDiff.file}: trivial-shape skip (no LLM call)`,
+      { color: 'gray' }
+    )
+    return {
+      ...fileDiff,
+      diff: trivialSummary,
+      tokenCount: tokenizer(trivialSummary),
+    }
+  }
+
   try {
     const fileSummary = await summarize(
       [
diff --git a/src/lib/parsers/default/utils/trivialDiff.test.ts b/src/lib/parsers/default/utils/trivialDiff.test.ts
new file mode 100644
index 0000000..902223c
--- /dev/null
+++ b/src/lib/parsers/default/utils/trivialDiff.test.ts
@@ -0,0 +1,145 @@
+import { FileDiff } from '../../../types'
+import {
+  detectTrivialDiffShape,
+  summarizeTrivialDiff,
+} from './trivialDiff'
+
+const additionDiff = `diff --git a/foo.ts b/foo.ts
+new file mode 100644
+index 0000000..1234567
+--- /dev/null
++++ b/foo.ts
+@@ -0,0 +1,3 @@
++export const foo = 1
++export const bar = 2
++export const baz = 3
+`
+
+const deletionDiff = `diff --git a/legacy.ts b/legacy.ts
+deleted file mode 100644
+index 1234567..0000000
+--- a/legacy.ts
++++ /dev/null
+@@ -1,3 +0,0 @@
+-export const legacy = 1
+-export const old = 2
+-export const stale = 3
+`
+
+const renameDiff = `diff --git a/old/path.ts b/new/path.ts
+similarity index 100%
+rename from old/path.ts
+rename to new/path.ts
+`
+
+const binaryDiff = `diff --git a/assets/logo.png b/assets/logo.png
+Binary files a/assets/logo.png and b/assets/logo.png differ
+`
+
+const modificationDiff = `diff --git a/src/foo.ts b/src/foo.ts
+index 1234567..89abcde 100644
+--- a/src/foo.ts
++++ b/src/foo.ts
+@@ -1,5 +1,7 @@
+ const foo = 1
+-const bar = 2
++const bar = 22
++const baz = 3
+ const quux = 4
+`
+
+const renameWithEditDiff = `diff --git a/old/path.ts b/new/path.ts
+similarity index 87%
+rename from old/path.ts
+rename to new/path.ts
+@@ -1,3 +1,4 @@
+ const foo = 1
+-const bar = 2
++const bar = 22
++const baz = 3
+`
+
+describe('detectTrivialDiffShape', () => {
+  it('detects pure additions', () => {
+    expect(detectTrivialDiffShape(additionDiff)).toBe('addition')
+  })
+
+  it('detects pure deletions', () => {
+    expect(detectTrivialDiffShape(deletionDiff)).toBe('deletion')
+  })
+
+  it('detects pure renames (no body)', () => {
+    expect(detectTrivialDiffShape(renameDiff)).toBe('rename')
+  })
+
+  it('detects binary file changes', () => {
+    expect(detectTrivialDiffShape(binaryDiff)).toBe('binary')
+  })
+
+  it('returns undefined for modifications (mixed +/-)', () => {
+    expect(detectTrivialDiffShape(modificationDiff)).toBeUndefined()
+  })
+
+  it('returns undefined for renames that also include edits (rename + body)', () => {
+    expect(detectTrivialDiffShape(renameWithEditDiff)).toBeUndefined()
+  })
+
+  it('returns undefined for empty input', () => {
+    expect(detectTrivialDiffShape('')).toBeUndefined()
+  })
+
+  it('ignores +++ / --- header markers when classifying', () => {
+    // The `+++ b/file` and `--- a/file` headers shouldn't fool the
+    // counter — they're metadata, not content.
+    expect(detectTrivialDiffShape(additionDiff)).toBe('addition')
+    expect(detectTrivialDiffShape(deletionDiff)).toBe('deletion')
+  })
+})
+
+describe('summarizeTrivialDiff', () => {
+  function makeDiff(file: string, diff: string): FileDiff {
+    return { file, diff, summary: '', tokenCount: 100 }
+  }
+
+  it('templated summary for pure addition includes line count', () => {
+    expect(summarizeTrivialDiff(makeDiff('foo.ts', additionDiff)))
+      .toBe('Added `foo.ts` (3 lines).')
+  })
+
+  it('templated summary for pure deletion includes line count', () => {
+    expect(summarizeTrivialDiff(makeDiff('legacy.ts', deletionDiff)))
+      .toBe('Removed `legacy.ts` (3 lines).')
+  })
+
+  it('singular line wording when count is 1', () => {
+    const oneLine = `diff --git a/foo b/foo
+new file mode 100644
+--- /dev/null
++++ b/foo
+@@ -0,0 +1,1 @@
++only one line
+`
+    expect(summarizeTrivialDiff(makeDiff('foo', oneLine)))
+      .toBe('Added `foo` (1 line).')
+  })
+
+  it('rename summary names both old and new path', () => {
+    expect(summarizeTrivialDiff(makeDiff('new/path.ts', renameDiff)))
+      .toBe('Renamed `old/path.ts` → `new/path.ts`.')
+  })
+
+  it('binary summary is shape-only (no line count)', () => {
+    expect(summarizeTrivialDiff(makeDiff('assets/logo.png', binaryDiff)))
+      .toBe('Updated binary file `assets/logo.png`.')
+  })
+
+  it('returns undefined for modifications so the LLM path stays in charge', () => {
+    expect(summarizeTrivialDiff(makeDiff('src/foo.ts', modificationDiff)))
+      .toBeUndefined()
+  })
+
+  it('returns undefined for renames-with-edit', () => {
+    expect(summarizeTrivialDiff(makeDiff('new/path.ts', renameWithEditDiff)))
+      .toBeUndefined()
+  })
+})
diff --git a/src/lib/parsers/default/utils/trivialDiff.ts b/src/lib/parsers/default/utils/trivialDiff.ts
new file mode 100644
index 0000000..c62a42a
--- /dev/null
+++ b/src/lib/parsers/default/utils/trivialDiff.ts
@@ -0,0 +1,143 @@
+import { FileDiff } from '../../../types'
+
+/**
+ * Diff-shape detection + deterministic summarization for "trivial"
+ * diffs (#845). A trivial diff is one whose meaning is fully
+ * captured by its shape — pure additions, pure deletions, renames
+ * with no content change, and binary file changes — so an LLM
+ * summary adds nothing the templated string can't already convey.
+ *
+ * Used by the pre-process pass in `summarizeLargeFiles` to skip
+ * the LLM call for trivial files entirely. On the bench's
+ * pure-additions fixtures (initial commit, feature add) the wave
+ * consolidation often doesn't even fire afterward because the
+ * synthetic summaries collapse the directory token totals under
+ * the budget.
+ *
+ * Defensive about input shape: the helpers run before any other
+ * parsing, so a malformed diff (zero hunks, missing headers, weird
+ * formatting from a custom diff producer) should fall through as
+ * "modification" — the existing LLM path still handles it.
+ */
+
+export type TrivialDiffShape = 'addition' | 'deletion' | 'rename' | 'binary'
+
+/**
+ * Inspect a unified-diff string and report its shape, or undefined
+ * if the diff isn't trivial (mixed +/- lines, weird headers, etc.).
+ *
+ * Detection rules (cheap on purpose — we're called per-file and the
+ * goal is to skip work, not be exhaustive):
+ *
+ *   - `Binary files ... differ` header → 'binary'
+ *   - `rename from`/`rename to` headers and no `+`/`-` content
+ *     lines → 'rename'
+ *   - All content lines are `+` (and at least one is) → 'addition'
+ *   - All content lines are `-` (and at least one is) → 'deletion'
+ *   - Otherwise → undefined (let the LLM handle it)
+ */
+export function detectTrivialDiffShape(diff: string): TrivialDiffShape | undefined {
+  if (!diff) return undefined
+
+  // Binary marker is unambiguous and short-circuits early.
+  if (/^Binary files .+ and .+ differ$/m.test(diff)) {
+    return 'binary'
+  }
+
+  // Pure rename: git emits `rename from` / `rename to` and no body.
+  // We require BOTH markers AND no `+`/`-` content lines. Some
+  // renames-with-edit show rename headers AND a hunk; those should
+  // fall through to the LLM path.
+  const hasRenameFrom = /^rename from /m.test(diff)
+  const hasRenameTo = /^rename to /m.test(diff)
+  if (hasRenameFrom && hasRenameTo) {
+    const hasContentChange = diff
+      .split('\n')
+      .some((line) => isContentChangeLine(line))
+    if (!hasContentChange) {
+      return 'rename'
+    }
+  }
+
+  // Walk the body once classifying content lines. We skip header
+  // lines (diff --git, index, ---, +++, @@, etc.) and only inspect
+  // the lines that represent actual change content.
+  let plus = 0
+  let minus = 0
+  for (const line of diff.split('\n')) {
+    if (isHeaderLine(line)) continue
+    if (line.startsWith('+')) plus++
+    else if (line.startsWith('-')) minus++
+    // Context lines (' ' prefix) are ignored for shape classification:
+    // a pure addition can still have surrounding context if a hunk
+    // anchors at line 0, though `git diff` for a brand-new file
+    // typically has none.
+  }
+
+  if (plus > 0 && minus === 0) return 'addition'
+  if (minus > 0 && plus === 0) return 'deletion'
+  return undefined
+}
+
+/**
+ * Build a deterministic summary string for a trivial diff. Returns
+ * undefined when the shape can't be templated (caller should fall
+ * back to the LLM path).
+ */
+export function summarizeTrivialDiff(fileDiff: FileDiff): string | undefined {
+  const shape = detectTrivialDiffShape(fileDiff.diff)
+  if (!shape) return undefined
+
+  const lineCount = countContentLines(fileDiff.diff, shape)
+  switch (shape) {
+    case 'addition':
+      return `Added \`${fileDiff.file}\` (${lineCount} line${lineCount === 1 ? '' : 's'}).`
+    case 'deletion':
+      return `Removed \`${fileDiff.file}\` (${lineCount} line${lineCount === 1 ? '' : 's'}).`
+    case 'rename': {
+      const oldPath = extractRenameOldPath(fileDiff.diff)
+      return oldPath
+        ? `Renamed \`${oldPath}\` → \`${fileDiff.file}\`.`
+        : `Renamed file to \`${fileDiff.file}\`.`
+    }
+    case 'binary':
+      return `Updated binary file \`${fileDiff.file}\`.`
+  }
+}
+
+function isHeaderLine(line: string): boolean {
+  return (
+    line.startsWith('diff --git') ||
+    line.startsWith('index ') ||
+    line.startsWith('--- ') ||
+    line.startsWith('+++ ') ||
+    line.startsWith('@@') ||
+    line.startsWith('new file mode') ||
+    line.startsWith('deleted file mode') ||
+    line.startsWith('similarity index') ||
+    line.startsWith('rename from ') ||
+    line.startsWith('rename to ') ||
+    line.startsWith('Binary files ')
+  )
+}
+
+function isContentChangeLine(line: string): boolean {
+  if (isHeaderLine(line)) return false
+  return line.startsWith('+') || line.startsWith('-')
+}
+
+function countContentLines(diff: string, shape: TrivialDiffShape): number {
+  if (shape === 'binary' || shape === 'rename') return 0
+  const prefix = shape === 'addition' ? '+' : '-'
+  let count = 0
+  for (const line of diff.split('\n')) {
+    if (isHeaderLine(line)) continue
+    if (line.startsWith(prefix)) count++
+  }
+  return count
+}
+
+function extractRenameOldPath(diff: string): string | undefined {
+  const match = diff.match(/^rename from (.+)$/m)
+  return match ? match[1].trim() : undefined
+}