{
 "measurement": "A parallel fan-out lands in one of two execution modes, and they differ by 53% in cost",
 "claude_code_version": "2.1.228 (Claude Code)",
 "method": {
  "task": "N parallel subagents each create one file containing DONE.",
  "isolation": "--setting-sources project on the 26 runs the analysis uses, matching the arm the published 20,398 per-agent figure came from, and asserted onto the command line rather than assumed. The file also carries 8 runs from a separate configured-settings arm marked isolated: false; they are published for completeness and no figure uses them.",
  "arrival_control": "N files must exist on disk. files_created is published per run so the check is verifiable rather than asserted. 34 of 34 passed.",
  "tokens": "modelUsage summed over inputTokens + cacheCreationInputTokens + cacheReadInputTokens. Not .usage, which does not count subagent tokens at all.",
  "partition": "Runs are separated by num_turns as reported by the CLI in the result JSON. No mechanism is claimed for why the modes differ."
 },
 "runs": {
  "width_sweep_n2_n4_n8": [
   {
    "n": 2,
    "round": 0,
    "status": "ok",
    "files_created": 2,
    "context_tokens": 85435,
    "output_tokens": 1106,
    "turns": 3,
    "cost_usd": 0.21608549999999999,
    "wall": 15.2,
    "reply": "FINISHED"
   },
   {
    "n": 4,
    "round": 0,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 125773,
    "output_tokens": 1742,
    "turns": 5,
    "cost_usd": 0.261717,
    "wall": 18.5,
    "reply": "FINISHED"
   },
   {
    "n": 8,
    "round": 0,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 207570,
    "output_tokens": 3840,
    "turns": 9,
    "cost_usd": 0.45153500000000013,
    "wall": 29.9,
    "reply": "FINISHED"
   },
   {
    "n": 2,
    "round": 1,
    "status": "ok",
    "files_created": 2,
    "context_tokens": 85455,
    "output_tokens": 1115,
    "turns": 3,
    "cost_usd": 0.18207949999999995,
    "wall": 15.8,
    "reply": "FINISHED"
   },
   {
    "n": 4,
    "round": 1,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 126173,
    "output_tokens": 2169,
    "turns": 5,
    "cost_usd": 0.276345,
    "wall": 21.9,
    "reply": "FINISHED"
   },
   {
    "n": 8,
    "round": 1,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 207041,
    "output_tokens": 3577,
    "turns": 9,
    "cost_usd": 0.4414659999999999,
    "wall": 29.4,
    "reply": "FINISHED"
   },
   {
    "n": 2,
    "round": 2,
    "status": "ok",
    "files_created": 2,
    "context_tokens": 85380,
    "output_tokens": 1054,
    "turns": 3,
    "cost_usd": 0.1797645,
    "wall": 17.5,
    "reply": "FINISHED"
   },
   {
    "n": 4,
    "round": 2,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 125853,
    "output_tokens": 1770,
    "turns": 5,
    "cost_usd": 0.2686305,
    "wall": 22.6,
    "reply": "FINISHED"
   },
   {
    "n": 8,
    "round": 2,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 318155,
    "output_tokens": 3553,
    "turns": 1,
    "cost_usd": 0.58908,
    "wall": 31.9,
    "reply": "FINISHED"
   },
   {
    "n": 2,
    "round": 3,
    "status": "ok",
    "files_created": 2,
    "context_tokens": 85432,
    "output_tokens": 1104,
    "turns": 3,
    "cost_usd": 0.18157449999999997,
    "wall": 15.4,
    "reply": "FINISHED"
   },
   {
    "n": 4,
    "round": 3,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 125869,
    "output_tokens": 1780,
    "turns": 5,
    "cost_usd": 0.2688675,
    "wall": 20.5,
    "reply": "FINISHED"
   },
   {
    "n": 8,
    "round": 3,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 207102,
    "output_tokens": 3514,
    "turns": 9,
    "cost_usd": 0.43961300000000003,
    "wall": 28.3,
    "reply": "FINISHED"
   },
   {
    "n": 2,
    "round": 4,
    "status": "ok",
    "files_created": 2,
    "context_tokens": 85932,
    "output_tokens": 1281,
    "turns": 3,
    "cost_usd": 0.18884949999999998,
    "wall": 19.0,
    "reply": "FINISHED"
   },
   {
    "n": 4,
    "round": 4,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 126181,
    "output_tokens": 2164,
    "turns": 5,
    "cost_usd": 0.27635999999999994,
    "wall": 20.7,
    "reply": "FINISHED"
   },
   {
    "n": 8,
    "round": 4,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 208190,
    "output_tokens": 4039,
    "turns": 9,
    "cost_usd": 0.4600577499999999,
    "wall": 36.8,
    "reply": "FINISHED"
   },
   {
    "n": 2,
    "round": 5,
    "status": "ok",
    "files_created": 2,
    "context_tokens": 85465,
    "output_tokens": 1125,
    "turns": 3,
    "cost_usd": 0.182383,
    "wall": 17.8,
    "reply": "FINISHED"
   },
   {
    "n": 4,
    "round": 5,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 125902,
    "output_tokens": 1791,
    "turns": 5,
    "cost_usd": 0.26368199999999997,
    "wall": 20.9,
    "reply": "FINISHED"
   },
   {
    "n": 8,
    "round": 5,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 207283,
    "output_tokens": 3692,
    "turns": 9,
    "cost_usd": 0.44521275000000005,
    "wall": 30.9,
    "reply": "FINISHED"
   }
  ],
  "reverification_isolated_and_configured": [
   {
    "arm": "isolated",
    "n": 1,
    "isolated": true,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 65049,
    "cost_usd": 0.16891425,
    "turns": 2,
    "wall": 22.9
   },
   {
    "arm": "isolated",
    "n": 8,
    "isolated": true,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 205419,
    "cost_usd": 0.4153555,
    "turns": 9,
    "wall": 21.3
   },
   {
    "arm": "configured",
    "n": 1,
    "isolated": false,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 213485,
    "cost_usd": 0.8261452499999999,
    "turns": 2,
    "wall": 22.1
   },
   {
    "arm": "configured",
    "n": 4,
    "isolated": false,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 492117,
    "cost_usd": 1.678636,
    "turns": 5,
    "wall": 26.0
   },
   {
    "arm": "isolated",
    "n": 1,
    "isolated": true,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 64828,
    "cost_usd": 0.13152525,
    "turns": 2,
    "wall": 12.8
   },
   {
    "arm": "isolated",
    "n": 8,
    "isolated": true,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 314419,
    "cost_usd": 0.5663035000000001,
    "turns": 1,
    "wall": 24.6
   },
   {
    "arm": "configured",
    "n": 1,
    "isolated": false,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 213347,
    "cost_usd": 0.7828450000000001,
    "turns": 2,
    "wall": 17.5
   },
   {
    "arm": "configured",
    "n": 4,
    "isolated": false,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 490834,
    "cost_usd": 1.6643352500000002,
    "turns": 5,
    "wall": 24.6
   },
   {
    "arm": "isolated",
    "n": 1,
    "isolated": true,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 64840,
    "cost_usd": 0.13151425,
    "turns": 2,
    "wall": 12.9
   },
   {
    "arm": "isolated",
    "n": 8,
    "isolated": true,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 205737,
    "cost_usd": 0.4244165,
    "turns": 9,
    "wall": 22.3
   },
   {
    "arm": "configured",
    "n": 1,
    "isolated": false,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 213599,
    "cost_usd": 0.7897095000000001,
    "turns": 2,
    "wall": 18.3
   },
   {
    "arm": "configured",
    "n": 4,
    "isolated": false,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 490804,
    "cost_usd": 1.6579369999999998,
    "turns": 5,
    "wall": 21.8
   },
   {
    "arm": "isolated",
    "n": 1,
    "isolated": true,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 64961,
    "cost_usd": 0.1308605,
    "turns": 2,
    "wall": 13.1
   },
   {
    "arm": "isolated",
    "n": 8,
    "isolated": true,
    "status": "ok",
    "files_created": 8,
    "context_tokens": 317786,
    "cost_usd": 0.5566162499999998,
    "turns": 1,
    "wall": 30.2
   },
   {
    "arm": "configured",
    "n": 1,
    "isolated": false,
    "status": "ok",
    "files_created": 1,
    "context_tokens": 213118,
    "cost_usd": 0.780073,
    "turns": 2,
    "wall": 18.8
   },
   {
    "arm": "configured",
    "n": 4,
    "isolated": false,
    "status": "ok",
    "files_created": 4,
    "context_tokens": 490683,
    "cost_usd": 1.655558,
    "turns": 5,
    "wall": 22.0
   }
  ]
 },
 "results": {
  "headline": "The same eight-agent fan-out runs in two modes. The expensive one costs 1.534x the cheap one for the same delivered files, and it occurred in 3 of 10 isolated runs.",
  "the_ratio_and_its_inputs_are_real": {
   "cheap_mode_median_context": 207102,
   "produced_by_a_run": true,
   "runs": [
    205419,
    205737,
    207041,
    207102,
    207283,
    207570,
    208190
   ],
   "expensive_mode_median_context": 317786,
   "produced_by_a_run_2": true,
   "runs_2": [
    314419,
    317786,
    318155
   ],
   "ratio": 1.5344,
   "percent_more": 53.4,
   "note": "Both medians are odd-n and were each produced by an actual run, so the headline figure does not depend on any interpolated value."
  },
  "PHANTOM_MEDIANS_CORRECTED_2026_08_22": {
   "what_was_wrong": "Four figures published from this corpus were medians of EVEN-sized samples, i.e. the midpoint of the two middle runs, and no run produced any of them.",
   "the_phantoms": {
    "64,900.5": {
     "was": "the one-agent baseline the per-agent figures subtract",
     "runs": [
      64828,
      64840,
      64961,
      65049
     ],
     "midpoint_of": [
      64840,
      64961
     ],
     "produced_by_a_run": false
    },
    "125,885.5": {
     "was": "median context at four agents",
     "runs": [
      125773,
      125853,
      125869,
      125902,
      126173,
      126181
     ],
     "midpoint_of": [
      125869,
      125902
     ],
     "produced_by_a_run": false
    },
    "85,445": {
     "was": "median context at two agents",
     "runs": [
      85380,
      85432,
      85435,
      85455,
      85465,
      85932
     ],
     "midpoint_of": [
      85435,
      85455
     ],
     "produced_by_a_run": false,
     "note": "A WHOLE NUMBER, because the two middle runs differ by an even amount. This is why a scan for a .5 ending cannot catch every phantom."
    },
    "20,314.5 and 36,126.5": {
     "was": "tokens per added agent, both modes",
     "why_wrong": "arithmetically exact, but computed by subtracting the phantom 64,900.5 baseline"
    }
   },
   "what_replaces_them": "the observed n=1 RANGE rather than a point, which needs no estimator and cannot be a phantom. The two modes still do not overlap, which is the finding.",
   "one_agent_observed_range": {
    "min": 64828,
    "max": 65049,
    "n": 4,
    "runs": [
     64828,
     64840,
     64961,
     65049
    ]
   },
   "tokens_per_added_agent": {
    "cheap_mode": {
     "low": 20293,
     "high": 20325
    },
    "expensive_mode": {
     "low": 36105,
     "high": 36137
    },
    "arms_overlap": false
   },
   "median_context_by_width_stated_as_ranges": {
    "2_agents": {
     "n": 6,
     "min": 85380,
     "max": 85932
    },
    "4_agents": {
     "n": 6,
     "min": 125773,
     "max": 126181
    },
    "8_agents_cheap": {
     "n": 7,
     "median": 207102,
     "produced_by_a_run": true
    }
   },
   "what_did_NOT_change": "the headline. 1.534x and +53.4% are the ratio of two real medians and are unaffected; so is the 3-of-10 occurrence rate."
  }
 }
}