> ## Documentation Index
> Fetch the complete documentation index at: https://docs.promptlayer.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Column Types
> Reference for text columns, computed columns, evaluation columns, helper columns, and composition in Tables.
Table column types reuse PromptLayer's evaluation and workflow building blocks, plus the Tables-specific **Composition** type.
## How sources work
Computed columns read from source columns in the sheet. For example, a `Prompt output` column can map a prompt variable to `Customer message`, and a `Quality score` column can read from `Prompt output`. If a source changes, dependent computed cells can become stale.
## Column type overview
| UI label | Type value | Category | Use when |
| ------------------------- | --------------------------- | ----------------------- | --------------------------------------------------------------------------- |
| Text | `TEXT` | Text | You need editable input data, expected answers, labels, metadata, or notes. |
| Prompt Template | `PROMPT_TEMPLATE` | Data source / execution | You want to run a Prompt Registry template or inline prompt for each row. |
| Workflow | `WORKFLOW` | Data source / execution | You want a row to execute a PromptLayer workflow. |
| Code Execution | `CODE_EXECUTION` | Data source / execution | You need Python or JavaScript logic per row. |
| Endpoint | `ENDPOINT` | Data source / execution | You want to send row data to an external URL endpoint. |
| MCP | `MCP` | Data source / execution | You want to call Model Context Protocol server functions. |
| Conversation Simulator | `CONVERSATION_SIMULATOR` | Data source / execution | You want to simulate a multi-turn user and assistant conversation. |
| Human | `HUMAN` | Data source / execution | You need a human to fill in or approve data. |
| While Loop | `WHILE_LOOP` | Data source / execution | You need repeated execution while a condition remains true. |
| For Loop | `FOR_LOOP` | Data source / execution | You need to iterate over a collection or array. |
| Composition | `COMPOSITION` | Data source / execution | You want to reference data from another sheet or table. |
| Compare | `COMPARE` | Simple eval | You want to compare values and generate a diff or comparison result. |
| Contains | `CONTAINS` | Simple eval | You want to check whether text contains a substring. |
| Regex | `REGEX` | Simple eval | You want to validate text against a regular expression. |
| Absolute Numeric Distance | `ABSOLUTE_NUMERIC_DISTANCE` | Simple eval | You want the absolute distance between numeric values. |
| Assert Valid | `ASSERT_VALID` | Simple eval | You want to validate data types or formats. |
| Math Operator | `MATH_OPERATOR` | Simple eval | You want mathematical comparisons such as greater than or less than. |
| LLM Assertion | `LLM_ASSERTION` | LLM eval | You want an LLM to judge whether an assertion is true. |
| AI Data Extraction | `AI_DATA_EXTRACTION` | LLM eval | You want an LLM to extract specific information from text. |
| Cosine Similarity | `COSINE_SIMILARITY` | LLM eval | You want semantic similarity between vectors or text embeddings. |
| JSON Extraction | `JSON_PATH` | Helper | You want to extract values from JSON with JSONPath. |
| XML Path | `XML_PATH` | Helper | You want to extract values from XML with XPath. |
| Regex Extraction | `REGEX_EXTRACTION` | Helper | You want to extract capture groups from text. |
| Parse Value | `PARSE_VALUE` | Helper | You want to parse a specific value from structured or unstructured data. |
| Count | `COUNT` | Helper | You want counts of elements, characters, or occurrences. |
| Min Max | `MIN_MAX` | Helper | You want the minimum or maximum value from numeric inputs. |
| Coalesce | `COALESCE` | Helper | You want the first non-null value from several sources. |
| Combine Columns | `COMBINE_COLUMNS` | Helper | You want to merge values from multiple sources into one output. |
| Apply Diff | `APPLY_DIFF` | Helper | You want to apply a unified diff patch to text. |
**Condition** appears in Workflow node selectors, but it is not a Table column type. Use Table-supported comparison, assertion, or helper columns for row-level checks.
## Composition
Composition references a source table, sheet, and column, then pulls that value into the current sheet. Use it when multiple sheets should share a reusable intermediate result instead of copying logic.
## API references
Use the generated API reference for exact request schemas when creating or updating columns programmatically.
Create text or computed columns.
Update title, config, and dependencies.