{
  "registry_version": "tteop-metrics/0.1-draft",
  "registry_maturity": "experimental",
  "last_updated": "2026-08-28",
  "metrics": [
    {
      "metric_id": "tteop.yield",
      "name": "Yield",
      "symbol": "\u03a5",
      "maturity": "experimental",
      "formula": "(cache_read \u00d7 output) / input\u00b2",
      "equivalent": "Leverage \u00d7 Velocity",
      "input_requirements": [
        "input > 0",
        "cache_read is not null"
      ],
      "valid_domain": "[0, +\u221e)",
      "zero_behavior": "Yield = 0 when cache_read = 0 or output = 0 (and input > 0)",
      "missingness_behavior": "null when input = 0 or cache_read is null",
      "aggregation_behavior": "Compute from aggregated sums, not averaged from per-request values",
      "normalization_profile": "None normative in v0.1. Proposed profiles in metrics/normalization-profiles.md: window-normalized (\u03a5_w), linear-input (\u03a5_lin), sqrt-input (\u03a5_sqrt), log-yield (log_\u03a5). All experimental, deferred to v0.2 via TEP.",
      "interpretation": "A composite signal combining cache reuse (Leverage) and output generation (Velocity). Higher values indicate more output per unit of fresh input, amplified by cache reuse.",
      "prohibited_interpretation": "Must not be presented as proof of code quality, productivity, task success, employee performance, or business impact.",
      "known_limitations": [
        "Quadratically sensitive to input scale due to input\u00b2 in denominator",
        "Non-monotonic: doubling both input and output (same ratio) halves Yield if cache_read is constant",
        "Not comparable across observation windows of different granularity without disclosure"
      ],
      "security_gaming_considerations": [
        "An operator can inflate Yield by maximizing cache_read (reusing cached context) while minimizing fresh input",
        "An operator can inflate Yield by generating verbose output",
        "Anti-gaming is a platform-layer concern, not a protocol concern"
      ],
      "rounding": {
        "decimal_places": 2,
        "mode": "round-half-to-even"
      },
      "test_vectors": [
        {
          "id": "canonical-moses",
          "input": 1251211,
          "output": 11296121,
          "cache_write": 128196310,
          "cache_read": 2555179769,
          "expected_value": 18436.98
        },
        {
          "id": "zero-cache-read",
          "input": 1000,
          "output": 500,
          "cache_write": 200,
          "cache_read": 0,
          "expected_value": 0.0
        },
        {
          "id": "zero-input",
          "input": 0,
          "output": 500,
          "cache_write": 200,
          "cache_read": 1000,
          "expected_value": null
        },
        {
          "id": "missing-cache-read",
          "input": 1000,
          "output": 500,
          "cache_write": 200,
          "cache_read": null,
          "expected_value": null
        }
      ],
      "legacy_aliases": [
        "yield"
      ],
      "spec_section": "SPEC.md \u00a726.1"
    },
    {
      "metric_id": "tteop.leverage",
      "name": "Leverage",
      "symbol": "L",
      "maturity": "experimental",
      "formula": "cache_read / input",
      "input_requirements": [
        "input > 0",
        "cache_read is not null"
      ],
      "valid_domain": "[0, +\u221e)",
      "zero_behavior": "Leverage = 0 when cache_read = 0 (and input > 0)",
      "missingness_behavior": "null when input = 0 or cache_read is null",
      "aggregation_behavior": "Compute from aggregated sums, not averaged from per-request values",
      "normalization_profile": "None normative in v0.1. See metrics/normalization-profiles.md for proposed profiles.",
      "interpretation": "How much cached context an operator reuses relative to fresh input. Higher values indicate greater cache utilization.",
      "prohibited_interpretation": "Must not be presented as proof of skill, productivity, or efficiency in any absolute sense.",
      "known_limitations": [
        "Sensitive to provider caching policy: providers with aggressive caching will produce higher Leverage",
        "Not comparable across providers without adapter disclosure",
        "Can be gamed by artificially reducing fresh input"
      ],
      "security_gaming_considerations": [
        "An operator can inflate Leverage by minimizing fresh input tokens (e.g., very short prompts with large cached context)",
        "Provider caching policy changes can cause artificial Leverage shifts unrelated to operator behavior"
      ],
      "rounding": {
        "decimal_places": 1,
        "mode": "round-half-to-even"
      },
      "test_vectors": [
        {
          "id": "canonical-moses",
          "input": 1251211,
          "output": 11296121,
          "cache_write": 128196310,
          "cache_read": 2555179769,
          "expected_value": 2042.2
        },
        {
          "id": "zero-cache-read",
          "input": 1000,
          "output": 500,
          "cache_write": 200,
          "cache_read": 0,
          "expected_value": 0.0
        },
        {
          "id": "zero-input",
          "input": 0,
          "output": 500,
          "cache_write": 200,
          "cache_read": 1000,
          "expected_value": null
        }
      ],
      "legacy_aliases": [
        "leverage"
      ],
      "spec_section": "SPEC.md \u00a726.2"
    },
    {
      "metric_id": "tteop.velocity",
      "name": "Velocity",
      "symbol": "V",
      "maturity": "experimental",
      "formula": "output / input",
      "input_requirements": [
        "input > 0"
      ],
      "valid_domain": "[0, +\u221e)",
      "zero_behavior": "Velocity = 0 when output = 0 (and input > 0)",
      "missingness_behavior": "null when input = 0. Does not require cache fields.",
      "aggregation_behavior": "Compute from aggregated sums, not averaged from per-request values",
      "normalization_profile": "None normative in v0.1. See metrics/normalization-profiles.md for proposed profiles.",
      "interpretation": "How much output an operator generates relative to fresh input. Higher values indicate more output per unit of fresh input.",
      "prohibited_interpretation": "Must not be presented as proof of output quality, usefulness, or task success. High Velocity may indicate verbose, low-quality output.",
      "known_limitations": [
        "Does not account for output quality",
        "Sensitive to task type: code generation tasks may produce different Velocity than explanation tasks",
        "Can be gamed by generating verbose output"
      ],
      "security_gaming_considerations": [
        "An operator can inflate Velocity by generating unnecessarily verbose output",
        "An operator can inflate Velocity by minimizing fresh input (short prompts)"
      ],
      "rounding": {
        "decimal_places": 3,
        "mode": "round-half-to-even"
      },
      "test_vectors": [
        {
          "id": "canonical-moses",
          "input": 1251211,
          "output": 11296121,
          "cache_write": 128196310,
          "cache_read": 2555179769,
          "expected_value": 9.028
        },
        {
          "id": "zero-output",
          "input": 1000,
          "output": 0,
          "cache_write": 200,
          "cache_read": 1000,
          "expected_value": 0.0
        },
        {
          "id": "zero-input",
          "input": 0,
          "output": 500,
          "cache_write": 200,
          "cache_read": 1000,
          "expected_value": null
        }
      ],
      "legacy_aliases": [
        "velocity"
      ],
      "spec_section": "SPEC.md \u00a726.3"
    },
    {
      "metric_id": "tteop.output_fraction",
      "name": "output_fraction",
      "symbol": "F",
      "maturity": "experimental",
      "formula": "output / (input + output)",
      "input_requirements": [
        "input + output > 0"
      ],
      "valid_domain": "[0, 1]",
      "zero_behavior": "output_fraction = 0 when output = 0 (and input > 0)",
      "missingness_behavior": "null when input + output = 0. Does not require cache fields.",
      "aggregation_behavior": "Compute from aggregated sums, not averaged from per-request values",
      "normalization_profile": "None normative in v0.1. See metrics/normalization-profiles.md for proposed profiles.",
      "interpretation": "What fraction of total token flow (input + output) is output. A value of 0.9 means 90% of tokens are output.",
      "prohibited_interpretation": "Must not be presented as a signal-to-noise ratio. The name 'SNR' is a legacy alias and is misleading. This is an output fraction, not a signal-to-noise measure.",
      "known_limitations": [
        "Does not distinguish between useful and verbose output",
        "A high output_fraction does not indicate high-quality output",
        "The legacy name 'SNR' implies signal-processing semantics that this formula does not have"
      ],
      "security_gaming_considerations": [
        "An operator can inflate output_fraction by generating verbose output",
        "An operator can inflate output_fraction by minimizing fresh input"
      ],
      "rounding": {
        "decimal_places": 4,
        "mode": "round-half-to-even"
      },
      "test_vectors": [
        {
          "id": "canonical-moses",
          "input": 1251211,
          "output": 11296121,
          "cache_write": 128196310,
          "cache_read": 2555179769,
          "expected_value": 0.9003
        },
        {
          "id": "zero-output",
          "input": 1000,
          "output": 0,
          "cache_write": 200,
          "cache_read": 1000,
          "expected_value": 0.0
        },
        {
          "id": "zero-both",
          "input": 0,
          "output": 0,
          "cache_write": 0,
          "cache_read": 0,
          "expected_value": null
        }
      ],
      "legacy_aliases": [
        "snr"
      ],
      "spec_section": "SPEC.md \u00a726.4"
    },
    {
      "metric_id": "tteop.log_leverage",
      "name": "log_leverage",
      "symbol": "D",
      "maturity": "experimental",
      "formula": "log10(cache_read / input)",
      "equivalent": "log10(Leverage)",
      "input_requirements": [
        "input > 0",
        "output > 0",
        "cache_write > 0",
        "cache_read > 0"
      ],
      "valid_domain": "(-\u221e, +\u221e)",
      "zero_behavior": "Not applicable: requires all four pillars > 0. Zero in any pillar \u2192 null.",
      "missingness_behavior": "null when any of input, output, cache_write, cache_read is zero or null",
      "aggregation_behavior": "Compute from aggregated sums, not averaged from per-request values",
      "normalization_profile": "None normative in v0.1. log_\u03a5 = log_leverage + log10(Velocity) proposed in metrics/normalization-profiles.md as experimental.",
      "interpretation": "Logarithmic scale of cache reuse leverage. Compresses the wide dynamic range of Leverage into a more interpretable scale.",
      "prohibited_interpretation": "Must not be presented as a '10x developer' classification or developer productivity measure. The name '10xDEV' is a legacy alias that implies productivity, which the protocol explicitly disclaims.",
      "known_limitations": [
        "Requires all four pillars > 0, making it undefined for many real-world observations",
        "The reference implementation policy (all four pillars > 0) is stricter than the mathematical requirement (only input > 0 and cache_read > 0)",
        "The '10xDEV' label creates a false implication of developer productivity classification"
      ],
      "security_gaming_considerations": [
        "Same gaming opportunities as Leverage, compressed to a log scale",
        "The '10xDEV' name may incentivize gaming to reach a '10x' threshold"
      ],
      "rounding": {
        "decimal_places": 2,
        "mode": "round-half-to-even"
      },
      "test_vectors": [
        {
          "id": "canonical-moses",
          "input": 1251211,
          "output": 11296121,
          "cache_write": 128196310,
          "cache_read": 2555179769,
          "expected_value": 3.31
        },
        {
          "id": "zero-cache-write",
          "input": 1000,
          "output": 500,
          "cache_write": 0,
          "cache_read": 1000,
          "expected_value": null
        },
        {
          "id": "zero-output",
          "input": 1000,
          "output": 0,
          "cache_write": 200,
          "cache_read": 1000,
          "expected_value": null
        },
        {
          "id": "missing-cache",
          "input": 1000,
          "output": 500,
          "cache_write": null,
          "cache_read": null,
          "expected_value": null
        }
      ],
      "legacy_aliases": [
        "dev10x"
      ],
      "spec_section": "SPEC.md \u00a726.5"
    }
  ]
}