docs: document all execution modes (inline, stdin, script)

The -c flag supports semicolons for batching multiple commands in one
connection, and stdin piping works in quiet mode. These modes were
implemented but not documented, causing users to think batch execution
wasn't supported (issue #133).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ako

docs-site/src/appendixes/quick-reference.md

@@ -531,8 +531,9 @@ Cross-reference commands require `REFRESH CATALOG FULL` to populate reference da
 | Command | Syntax | Notes |
 |---------|--------|-------|
 | Interactive REPL | `mxcli` | Interactive MDL shell |
-| Execute command | `mxcli -p app.mpr -c "SHOW ENTITIES"` | Single command |
+| Inline commands | `mxcli -p app.mpr -c "CMD1; CMD2; CMD3"` | Semicolons batch multiple commands |
 | Execute script | `mxcli exec script.mdl -p app.mpr` | Script file |
+| Stdin piping | `echo "CMD" \| mxcli -p app.mpr` | Quiet mode, pipe-friendly |
 | Check syntax | `mxcli check script.mdl` | Parse-only validation |
 | Check references | `mxcli check script.mdl -p app.mpr --references` | With reference validation |
 | Lint project | `mxcli lint -p app.mpr [--format json\|sarif]` | 14 built-in + 27 Starlark rules |

docs-site/src/language/script-files.md

@@ -37,16 +37,51 @@ CREATE ASSOCIATION Sales.Order_Customer
   TYPE Reference;
 ```
 
-## Executing Scripts
+## Execution Modes
 
-### From the Command Line
+mxcli supports several ways to execute MDL. All modes open a single connection to the project — there is no per-command overhead.
 
-Use `mxcli exec` to run a script against a project:
+### Script File
+
+Use `mxcli exec` to run a `.mdl` file:
 
 ```bash
 mxcli exec setup_domain_model.mdl -p /path/to/app.mpr
 ```
 
+### Inline Commands (`-c`)
+
+Pass one or more semicolon-separated commands with the `-c` flag:
+
+```bash
+# Single command
+mxcli -p app.mpr -c "SHOW ENTITIES"
+
+# Multiple commands in one connection
+mxcli -p app.mpr -c "DESCRIBE ENTITY Sales.Customer; DESCRIBE ENTITY Sales.Order; SHOW MICROFLOWS IN Sales"
+```
+
+This is the fastest way for AI agents to batch multiple queries — all commands share a single connection.
+
+### Stdin Piping
+
+When stdin is a pipe (not a terminal), mxcli reads commands from it in quiet mode (no banner, no prompts):
+
+```bash
+# Pipe from echo
+echo "SHOW ENTITIES; SHOW MICROFLOWS" | mxcli -p app.mpr
+
+# Pipe from file
+mxcli -p app.mpr < commands.mdl
+
+# Pipe from heredoc
+mxcli -p app.mpr <<'EOF'
+DESCRIBE ENTITY Sales.Customer;
+DESCRIBE ENTITY Sales.Order;
+SHOW MICROFLOWS IN Sales;
+EOF
+```
+
 ### From the REPL
 
 Use `EXECUTE SCRIPT` inside an interactive session:

docs-site/src/reference/capabilities.md

@@ -120,8 +120,9 @@ Everything mxcli can do, organized by use case.
 
 | Capability | Command | Notes |
 |---|---|---|
-| Batch execution | `mxcli -p app.mpr -c "..."` | Non-interactive |
+| Inline commands | `mxcli -p app.mpr -c "CMD1; CMD2; CMD3"` | Semicolon-separated, single connection |
 | Script files | `mxcli exec script.mdl -p app.mpr` | Run MDL files |
+| Stdin piping | `echo "CMD" \| mxcli -p app.mpr` | Quiet mode, no prompts |
 | Docker build | `mxcli docker build -p app.mpr` | Build MDA in container |
 | Docker check | `mxcli docker check -p app.mpr` | Validate in container |
 | Testing | `mxcli test tests/ -p app.mpr` | `.test.mdl` / `.test.md` |