distributable, please

docker/distributable/packs/core/runtimes/README.md

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+# Core Pack Runtime Metadata
+
+This directory contains runtime metadata YAML files for the core pack. Each file defines a runtime environment that can be used to execute actions and sensors.
+
+## File Structure
+
+Each runtime YAML file contains only the fields that are stored in the database:
+
+- `ref` - Unique runtime reference (format: pack.name)
+- `pack_ref` - Pack this runtime belongs to
+- `name` - Human-readable runtime name
+- `description` - Brief description of the runtime
+- `distributions` - Runtime verification and capability metadata (JSONB)
+- `installation` - Installation requirements and metadata (JSONB)
+- `execution_config` - Interpreter, environment, dependency, and execution-time env var metadata
+
+## `execution_config.env_vars`
+
+Runtime authors can declare execution-time environment variables in a purely declarative way.
+
+String values replace the variable entirely:
+
+```yaml
+env_vars:
+  NODE_PATH: "{env_dir}/node_modules"
+```
+
+Object values support merge semantics against an existing value already present in the execution environment:
+
+```yaml
+env_vars:
+  PYTHONPATH:
+    operation: prepend
+    value: "{pack_dir}/lib"
+    separator: ":"
+```
+
+Supported operations:
+
+- `set` - Replace the variable with the resolved value
+- `prepend` - Add the resolved value before the existing value
+- `append` - Add the resolved value after the existing value
+
+Supported template variables:
+
+- `{pack_dir}`
+- `{env_dir}`
+- `{interpreter}`
+- `{manifest_path}`
+
+## Available Runtimes
+
+- **python.yaml** - Python 3 runtime for actions and sensors
+- **nodejs.yaml** - Node.js runtime for JavaScript-based actions and sensors
+- **shell.yaml** - Shell (bash/sh) runtime - always available
+- **native.yaml** - Native compiled runtime (Rust, Go, C, etc.) - executes binaries directly without an interpreter
+
+## Loading
+
+Runtime metadata files are loaded by the pack loading system and inserted into the `runtime` table in the database.