update docs

Author: tommaso-moro

CONTRIBUTING.md

@@ -39,6 +39,7 @@ These are one time installations required to be able to test your changes locall
     - Run linter: `script/lint`
     - Update snapshots and run tests: `UPDATE_TOOLSNAPS=true go test ./...`
     - Update readme documentation: `script/generate-docs`
+    - If renaming a tool, add a deprecation alias (see [Tool Renaming Guide](docs/tool-renaming.md))
 6. Push to your fork and [submit a pull request][pr] targeting the `main` branch
 7. Pat yourself on the back and wait for your pull request to be reviewed and merged.
 

docs/tool-renaming.md

@@ -0,0 +1,41 @@
+# Tool Renaming Guide
+
+How to safely rename MCP tools without breaking existing user configurations.
+
+## Overview
+
+When tools are renamed, users who have the old tool name in their MCP configuration (e.g., in `X-MCP-Tools` headers for the remote MCP server or `--tools` flags for the local MCP server) would normally get errors. The deprecation alias system allows us to maintain backward compatibility by silently resolving old tool names to their new canonical names.
+
+This allows us to rename tools safely, without introducing breaking changes for users that have a hard reference to those tools in their server configuration.
+
+## Quick Steps
+
+1. **Rename the tool** in your code (as usual, this will imply a range of changes like updating the tool registration, the tests and the toolsnaps).
+2. **Add a deprecation alias** in [pkg/github/deprecated_tool_aliases.go](../pkg/github/deprecated_tool_aliases.go):
+   ```go
+   var DeprecatedToolAliases = map[string]string{
+       "old_tool_name": "new_tool_name",
+   }
+   ```
+3. **Update documentation** (README, etc.) to reference the new canonical name
+
+That's it. The server will silently resolve old names to new ones. This will work across both local and remote MCP servers.
+
+## Example
+
+If renaming `get_issue` to `issue_read`:
+
+```go
+var DeprecatedToolAliases = map[string]string{
+    "get_issue": "issue_read",
+}
+```
+
+A user with this configuration:
+```json
+{
+  "--tools": "get_issue,get_file_contents"
+}
+```
+
+Will get `issue_read` and `get_file_contents` tools registered, with no errors.