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+---
+epic: 11
+story: 11.3
+title: "Output Formats"
+status: draft
+---
+
+## Epic 11 — CLI Tool
+**Goal:** Command-line tool for scripting and automation, same Rust engine.
+
+### Story 11.3: Output Formats
+
+As a developer,
+I want to control the output format of CalcPad results,
+So that I can integrate results into different toolchains and data pipelines.
+
+**Acceptance Criteria:**
+
+**Given** the user runs calcpad without a `--format` flag
+**When** the expression is evaluated
+**Then** the output is in plain text format (default), showing only the result value and unit
+
+**Given** the user runs `calcpad --format json "5kg in lbs"`
+**When** the expression is evaluated
+**Then** the output is valid JSON containing at minimum: `value`, `unit`, and `type` fields
+**And** example output resembles `{"value": 11.023, "unit": "lbs", "type": "mass"}`
+
+**Given** the user runs `calcpad --format csv` with multi-line stdin
+**When** the input is evaluated
+**Then** the output is CSV formatted with columns for line number, expression, value, and unit
+**And** the output can be directly imported into spreadsheet software
+
+**Given** the user specifies an unrecognized `--format` value
+**When** the command is executed
+**Then** an error message lists the valid format options (plain, json, csv)
+**And** the process exits with code 1