docs: add keyword-only args note to mcp-forge-conventions skill

.opencode/skills/mcp-forge-conventions/SKILL.md

@@ -18,6 +18,19 @@ mcp-forge injects tools using their **bare function name**, not the namespaced n
 
 The pattern: strip any server prefix (e.g. `searxng_`, `rag-mcp_`) and use only the function name.
 
+## Calling injected tools — keyword-only arguments
+
+Injected tool functions are **keyword-only wrappers**. Always pass arguments by name:
+
+```python
+# correct
+results = search(query="foo", language="en")
+page = fetch(url="https://example.com", max_chars=2000)
+
+# wrong — positional args raise TypeError
+results = search("foo")
+```
+
 ## Injection syntax
 
 Pass a JSON array of bare tool names to `mcp_tools`: