generate-bounds

name	generate-bounds
description	Use when the user wants to generate low/base/high assumption ranges (bounds) for missing or uncertain variables in a validated extract-parameters-from-full JSON, in preparation for deterministic scenarios or Monte Carlo

Generate Bounds for Extracted Parameters

Overview

Wraps the bounds-estimator system prompt at system-prompt.txt (next to this file) and applies it to a parameter JSON produced by extract-parameters-from-full (and ideally already passed validate-parameters). Output is a strict JSON object keyed by variable id, with low / base / high / unit / rationale / source for every variable that needs an assumption range.

Stage 4 of the pipeline described in planexe_simulator/README.md.

When to Use

• User asks to "generate bounds", "estimate ranges", "add low/base/high", or "prepare for scenarios" given an extract-parameters-from-full JSON
• User wants to fill in assumptions for missing_values_to_estimate and uncertain key_values before running deterministic scenarios or Monte Carlo
• Pipeline step between validate-parameters (passes clean) and generate-calculations / run-scenarios

Not for: regenerating the parameter JSON (use extract-parameters-from-full), validating the JSON (use validate-parameters), or producing Python code (use generate-calculations).

Workflow

1. Get the input JSON path. If the user did not provide one, ask. Do not guess.
2. Read system-prompt.txt (sibling of this SKILL.md). Its selection rules and spread heuristics are authoritative.
3. Read the parameter JSON. Assume it has already passed validate-parameters; if it visibly hasn't, tell the user and offer to validate first.
4. Produce the bounds JSON per the system prompt.
5. Self-audit before output. For each bound entry, verify:
   • Every numbered citation in rationale (Risk N, Issue N, Decision N) refers to content that substantively supports the claim — not just lexically present.
   • For variables feeding a declared gate threshold, the base-vs-threshold relationship is consistent with the rationale. If base implies base-case gate failure, the rationale names a report-internal anchor that justifies the shift.
   • source: "data" entries name an explicit anchor in the rationale.
   • For asymmetric bounds, the rationale notes the asymmetry's source. If any check fails, revise the bound; do not ship inconsistent state.
6. Output destination. Default: print the JSON to chat. If the user asks for a file, write to the path they specify. Suggested default file path: <input-basename>.bounds.json next to the input.

Selection Rules (re-stated for emphasis — see system prompt for full detail)

Generate one bounds entry for every id that meets ANY of:

• it appears in missing_values_to_estimate
• it is a key_value with value_type ∈ {inferred, missing_but_needed}
• it is a key_value with value == null
• it is a key_value with uncertainty == high
• it is a key_value with uncertainty == medium AND modelling_priority ∈ {critical, high}

Skip: explicit/derived key_values with low uncertainty, derived_questions, recommended_first_calculations, and formula LHS-only outputs that are not declared as inputs.

Spread by Uncertainty

Uncertainty	Spread around base
low	±10–20%
medium	±25–50%
high	≥±50%, up to a 2–5× factor when genuinely speculative

Always low ≤ base ≤ high. Fractions stay in [0, 1]. Counts of discrete things (people, kits, centers, months) use integer bounds.

Output Shape

{
  "<variable_id>": {
    "unit": "fraction",
    "low": 0.10,
    "base": 0.20,
    "high": 0.30,
    "rationale": "Short, ≤50 words. Include required disclosures when applicable.",
    "source": "data" | "assumption",
    "sampling_discipline": "fraction",
    "non_negative": true,
    "default_pass_probability": null
  }
}

Top-level is a single object keyed by variable id. Order keys roughly by importance (critical → high → medium → remaining missing values). Use "source": "data" only when the range is anchored in a citable real-world reference for similar programs; otherwise "assumption".

Sampling-discipline tag

Each entry MUST carry a sampling_discipline chosen by the LLM based on the variable's nature. Downstream consumers (run-scenarios, monte-carlo runner) read this tag directly and do not pattern-match on unit strings — so the LLM is the single authority for this classification.

Value	Meaning	Downstream behavior
"fixed"	low == base == high; genuinely pinned	Always return that value
"bernoulli_gate"	Binary pass/fail (staged funding, permit toggle, regulatory pass, conditional release). Requires default_pass_probability ∈ [0, 1]	Bernoulli draw; low on fail, high on pass
"integer"	Countable units — people, households, sites, kits, days, …	Sample continuously, round, re-clamp to [low, high]
"fraction"	Bounded fraction in [0, 1]	Clamp draws to [0, 1]
"continuous"	Real-valued; no rounding, no extra clamping beyond [low, high]	Plain triangular/uniform draw

non_negative is independent of discipline: set true when the variable cannot legitimately go below zero (continuous monetary amounts, counts, capacities); set false only when negative values are physically meaningful (a delta or net change variable).

default_pass_probability is required (a number in [0, 1]) when sampling_discipline == "bernoulli_gate" and MUST be null for every other discipline.

If no variable needs bounds, return {}.

Common Mistakes

Mistake	Fix
Bounding every variable, including known explicit facts	Skip explicit/derived key_values with low uncertainty — they are facts, not assumptions
Returning low == base == high for variables with real uncertainty	Give a real range; identical bounds are only for genuinely pinned KPI commitments
Wrapping output in ```json fences	Raw JSON only
Including derived_questions or recommended_first_calculations ids	Those are outputs/questions, not bounded inputs
Inventing ids that are not declared in the parameter JSON	Every key must correspond to a declared id in key_values or missing_values_to_estimate
Picking fractions outside [0, 1] (e.g. base 1.5 for a rate)	Clamp to the unit's natural range
Ignoring the parameter's uncertainty and giving everything the same ±20% spread	Anchor the spread on the parameter's stated uncertainty level
Rationale cites a numbered artifact (Risk N, Issue N, Decision N) that does not substantively support the claim	Re-read the cited artifact. The number must match content, not just exist in the report. If you cannot find a substantively correct citation, drop the citation and mark source: "assumption".
Shifting actual_X base past the X_target threshold without a report-internal anchor	Center base at the committed value unless a named Risk / Issue / Decision / premortem / expert-criticism passage forecasts a gap between commitment and reality. "Realistic execution" and "operational drift" are not anchors.
Generating bounds for a threshold or target variable (ids ending in _threshold, _target, _ceiling, _floor, _limit)	Thresholds enter the simulation as their stated single value. Randomising them silently changes what pass_rate measures and breaks the threshold_basis = report_explicit contract. Skip these variables.
Triangular bounds with base = high = target on a >= target gate variable (ring-fenced reserve, segregated escrow, allocation share, KPI floor that physically cannot overshoot)	The continuous triangular CDF has zero probability mass at the exact peak — the >= 0 margin gate fails ~100% of runs even when the commitment is intact. The Critical verdict you report is a property of the bound shape, not the plan. Switch to sampling_discipline: "bernoulli_gate" with low = shortfall floor (e.g. 0 or partial-segregation amount), high = the target, and default_pass_probability = realistic execution probability of the commitment (e.g. 0.95 for a signed escrow, 0.75 for a sponsor-committed reserve, 0.5 for a contested allocation). Bernoulli returns high on pass and low on fail, so the gate cleanly tests whether the commitment was executed.

Reference

• System prompt (authoritative): system-prompt.txt
• Pipeline overview and "what needs bounds" list: ../../README.md, Stage 4
• Companion skills: ../extract-parameters-from-full/SKILL.md, ../validate-parameters/SKILL.md
• Example input for testing: /tmp/extract-params-heatwave-v8.json (passes validate-parameters with valid: true)