You are an expert biotech trial analyst and prediction-market decision maker.

First estimate the intrinsic probability that the live trial question resolves YES from the trial facts alone. Then compare that view to the current market price and choose the best allowed action under the provided portfolio constraints.

Your task has two ordered stages.

Stage 1: Intrinsic forecast
- Use only the trial fields.
- Do not use market or portfolio fields when estimating intrinsic YES odds.
- Produce:
  - yesProbability: a number from 0 to 1
  - binaryCall: yes if yesProbability >= 0.5, otherwise no
  - confidence: integer from 50 to 100
  - reasoning: specific and decision-useful, at least 20 characters, target at most 400 characters, hard max 600 characters

Stage 2: Market action
- After forming the intrinsic forecast, compare it to the market price.
- Use market and portfolio fields only in this stage.
- Choose exactly one action from allowedActions.
- Use HOLD when the pricing gap is small, uncertainty is high, or constraints make the trade unattractive.
- amountUsd must be non-negative and must not exceed the relevant cap:
  - buy actions: maxBuyUsd
  - SELL_YES: maxSellYesUsd
  - SELL_NO: maxSellNoUsd
- If a sell action is not feasible, use HOLD.
- Size every action using only this market's price and the provided portfolio caps.
- action.explanation must be plain language and at most 220 characters.

General rules
- Output valid JSON only.
- No markdown.
- No extra keys.
- Do not restate the input.
- Keep forecast.reasoning focused on trial design, patient population, endpoint quality, prior data, operational execution, and disclosure risk.
- Keep forecast.reasoning at or under 400 characters when possible and never above 600 characters.
- Keep action.explanation focused on valuation and trade logic.

Input JSON:
{
  "meta": {
    "eventId": "trial-acme-ab101-phase-2",
    "trialQuestionId": "question-acme-ab101-positive-topline",
    "marketId": "market-acme-ab101-positive-topline",
    "modelId": "gpt-5.5",
    "asOf": "2026-07-15T14:30:00.000Z",
    "runDateIso": "2026-07-15T14:30:00.000Z"
  },
  "trial": {
    "displayTitle": "AB-101 Phase 2 topline readout",
    "sponsorName": "Acme Bio",
    "sponsorTicker": "ACME",
    "exactPhase": "Phase 2",
    "estPrimaryCompletionDate": "2026-08-31T00:00:00.000Z",
    "daysToPrimaryCompletion": 47,
    "indication": "Moderate-to-severe ulcerative colitis",
    "intervention": "AB-101 oral small molecule",
    "protocolPrimaryEndpoint": "Clinical remission at week 12",
    "marketPrimaryEndpoint": "Clinical remission at week 12",
    "primaryEndpoint": "Clinical remission at week 12",
    "currentStatus": "Active, not recruiting",
    "briefSummary": "Randomized placebo-controlled Phase 2 study evaluating AB-101 in adults with ulcerative colitis who had inadequate response to standard therapy.",
    "nctNumber": "NCT01234567",
    "questionPrompt": "Will AB-101 show a positive result on clinical remission at week 12?"
  },
  "market": {
    "yesPrice": 0.43,
    "noPrice": 0.57
  },
  "portfolio": {
    "cashAvailable": 1000,
    "yesSharesHeld": 0,
    "noSharesHeld": 0,
    "maxBuyUsd": 1000,
    "maxSellYesUsd": 0,
    "maxSellNoUsd": 0
  },
  "constraints": {
    "allowedActions": [
      "BUY_YES",
      "BUY_NO",
      "SELL_YES",
      "SELL_NO",
      "HOLD"
    ],
    "explanationMaxChars": 220
  }
}

Return exactly:
{
  "forecast": {
    "yesProbability": 0.0,
    "binaryCall": "no",
    "confidence": 50,
    "reasoning": "string"
  },
  "action": {
    "type": "HOLD",
    "amountUsd": 0,
    "explanation": "string"
  }
}

{
  "forecast": {
    "yesProbability": 0.61,
    "binaryCall": "yes",
    "confidence": 68,
    "reasoning": "Prior inflammatory bowel disease signal, endpoint clarity, and placebo-controlled design support a modest edge versus the current market line, though execution and durability risk remain material."
  },
  "action": {
    "type": "BUY_YES",
    "amountUsd": 100,
    "explanation": "Intrinsic odds look modestly above the current YES price."
  }
}

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "forecast",
    "action"
  ],
  "properties": {
    "forecast": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "yesProbability",
        "binaryCall",
        "confidence",
        "reasoning"
      ],
      "properties": {
        "yesProbability": {
          "type": "number",
          "minimum": 0,
          "maximum": 1
        },
        "binaryCall": {
          "type": "string",
          "enum": [
            "yes",
            "no"
          ]
        },
        "confidence": {
          "type": "integer",
          "minimum": 50,
          "maximum": 100
        },
        "reasoning": {
          "type": "string",
          "minLength": 20,
          "maxLength": 600
        }
      }
    },
    "action": {
      "type": "object",
      "additionalProperties": false,
      "required": [
        "type",
        "amountUsd",
        "explanation"
      ],
      "properties": {
        "type": {
          "type": "string",
          "enum": [
            "BUY_YES",
            "BUY_NO",
            "SELL_YES",
            "SELL_NO",
            "HOLD"
          ]
        },
        "amountUsd": {
          "type": "number",
          "minimum": 0
        },
        "explanation": {
          "type": "string",
          "minLength": 1,
          "maxLength": 220
        }
      }
    }
  }
}