Add Go as a supported output language

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- **Go output language**: `output_language: "go"` is now supported alongside python/javascript/typescript, generating a standard-library-first (`net/http`, `encoding/json`) Go program, with the same auth-hardcoding/refresh and bot-detection-fallback guidance as the other languages.
+
 ## [0.10.0] - 2026-06-01
 
 ### Changed

README.md

@@ -96,7 +96,7 @@ Settings live in `~/.reverse-api/config.json` and can be edited via `/settings`
 
 - **Models**: Sonnet 4.6 (default), Opus 4.6 (most capable), Haiku 4.5 (fastest). For OpenCode see [models.dev](https://models.dev).
 - **SDK**: `claude` (default), `opencode`, `cursor`, or `copilot` (GitHub Copilot).
-- **Output language**: `python`, `javascript`, or `typescript`.
+- **Output language**: `python`, `javascript`, `typescript`, or `go`.
 
 ## CLI
 

src/reverse_api/base_engineer.py

@@ -33,6 +33,7 @@ class BaseEngineer(ABC):
         "python": ".py",
         "javascript": ".js",
         "typescript": ".ts",
+        "go": ".go",
     }
 
     def __init__(
@@ -439,6 +440,7 @@ def _get_language_name(self) -> str:
             "python": "Python",
             "javascript": "JavaScript",
             "typescript": "TypeScript",
+            "go": "Go",
         }.get(self.output_language, "Python")
 
     def _get_existing_client_guidance(self) -> str:
@@ -467,6 +469,7 @@ def _get_run_command(self) -> str:
             "python": "python api_client.py",
             "javascript": "node api_client.js",
             "typescript": "npx tsx api_client.ts",
+            "go": "go run api_client.go",
         }.get(self.output_language, "python api_client.py")
 
     def _get_codegen_instructions(self) -> str:
@@ -576,6 +579,11 @@ def _get_auto_output_files(self, language_name: str, client_filename: str) -> st
             return base + f"\n3. `{self.scripts_dir}/package.json` - Only if external dependencies are needed"
         elif self.output_language == "typescript":
             return base + f"\n3. `{self.scripts_dir}/package.json` - Dependencies and run scripts"
+        elif self.output_language == "go":
+            return base + (
+                f"\n3. `{self.scripts_dir}/go.mod` and `{self.scripts_dir}/go.sum` - "
+                "Only if external dependencies are needed"
+            )
         return base
 
     @abstractmethod

src/reverse_api/cli.py

@@ -1083,6 +1083,7 @@ def handle_settings(mode_color=THEME_PRIMARY):
             Choice(title="python", value="python"),
             Choice(title="javascript", value="javascript"),
             Choice(title="typescript", value="typescript"),
+            Choice(title="go", value="go"),
             Choice(title="back", value="back"),
         ]
         lang = questionary.select(

src/reverse_api/config.py

@@ -20,7 +20,7 @@
     "opencode_model": "claude-opus-4-6",
     "opencode_provider": "anthropic",
     "output_dir": None,  # None means use ~/.reverse-api/runs
-    "output_language": "python",  # "python", "javascript", or "typescript"
+    "output_language": "python",  # "python", "javascript", "typescript", or "go"
     "real_time_sync": True,  # Enable real-time file sync during engineering
     "sdk": "claude",  # "claude", "opencode", "copilot", or "cursor"
 }

src/reverse_api/engineer.py

@@ -232,7 +232,7 @@ def run_reverse_engineering(
         cursor_setting_sources: Optional explicit list (overrides cursor_web_search), e.g. ["project","user","all"].
         enable_sync: Enable real-time file syncing during engineering
         is_fresh: Whether to start fresh (ignore previous scripts)
-        output_language: Target language - "python", "javascript", or "typescript"
+        output_language: Target language - "python", "javascript", "typescript", or "go"
         output_mode: Output mode - "client" for API client code, "docs" for OpenAPI specification
     """
     if sdk == "opencode":

src/reverse_api/prompts/__init__.py

@@ -54,7 +54,7 @@ def load_language_partial(language: str, **kwargs: str) -> str:
     """Load the language-specific codegen instructions partial.
 
     Args:
-        language: One of "python", "javascript", "typescript".
+        language: One of "python", "javascript", "typescript", "go".
         **kwargs: Placeholder values (scripts_dir, client_filename, run_command).
     """
     return load(f"partials/_language_{language}", **kwargs)

src/reverse_api/prompts/partials/_language_go.md

@@ -0,0 +1,24 @@
+**Generate a Go program** that replicates the API calls found in the traffic. The following are guidelines — use your judgment on what's appropriate for the specific API:
+
+- Prefer the standard library (`net/http`, `encoding/json`) — a single-file program with no external dependencies is the default; only introduce a module and third-party packages if the API genuinely needs something the standard library doesn't provide (e.g. a specific auth scheme's signing library)
+- Reuse one `*http.Client` (with cookie jar if the API relies on cookies) across requests rather than creating a new one per call
+- Create a separate function for each distinct API endpoint, with a typed struct for its response shape
+- Return errors rather than panicking; wrap them with context (`fmt.Errorf("...: %w", err)`)
+- Include a `main` function with example usage
+
+**Authentication & credentials:**
+- Hardcode all cookies, tokens, session IDs, and auth headers found in the traffic directly in the program
+- The user should be able to run the program immediately with zero configuration — no env vars, no config files, no manual setup
+- If the API uses cookies, set them via the client's cookie jar
+- If the API uses Bearer tokens or API keys, hardcode them in the request headers
+- Handle auth refresh so the program doesn't go stale: if you see a token refresh endpoint, OAuth refresh flow, or login endpoint in the traffic, implement automatic re-authentication when a request returns 401/403. If cookies have expiry, re-fetch them before they expire
+
+**Testing:**
+- If a module was initialized, first run: `go mod tidy`
+- Format the code with: `gofmt -w {client_filename}`
+- Run with: `{run_command}`
+- You have up to 5 attempts to fix issues
+
+Save the program to: `{scripts_dir}/{client_filename}`
+Save documentation to: `{scripts_dir}/README.md`
+If external dependencies are used, save the module files: `{scripts_dir}/go.mod` and `{scripts_dir}/go.sum`

tests/test_base_engineer.py

@@ -193,6 +193,11 @@ def test_get_output_extension_typescript(self, tmp_path):
         eng = self._make_engineer(tmp_path, output_language="typescript")
         assert eng._get_output_extension() == ".ts"
 
+    def test_get_output_extension_go(self, tmp_path):
+        """Go extension."""
+        eng = self._make_engineer(tmp_path, output_language="go")
+        assert eng._get_output_extension() == ".go"
+
     def test_get_output_extension_unknown(self, tmp_path):
         """Unknown language defaults to .py."""
         eng = self._make_engineer(tmp_path, output_language="rust")
@@ -223,6 +228,11 @@ def test_get_run_command_typescript(self, tmp_path):
         eng = self._make_engineer(tmp_path, output_language="typescript")
         assert eng._get_run_command() == "npx tsx api_client.ts"
 
+    def test_get_run_command_go(self, tmp_path):
+        """Run command for Go."""
+        eng = self._make_engineer(tmp_path, output_language="go")
+        assert eng._get_run_command() == "go run api_client.go"
+
     def test_get_run_command_unknown(self, tmp_path):
         """Unknown language defaults to Python command."""
         eng = self._make_engineer(tmp_path, output_language="rust")
@@ -269,6 +279,13 @@ def test_typescript_prompt(self, tmp_path):
         assert "TypeScript module" in system_prompt
         assert "interfaces" in system_prompt
 
+    def test_go_prompt(self, tmp_path):
+        """Go prompt includes Go-specific instructions."""
+        eng = self._make_engineer(tmp_path, output_language="go")
+        system_prompt, user_message = eng._build_prompts()
+        assert "Go program" in system_prompt
+        assert "net/http" in system_prompt
+
     def test_docs_prompt(self, tmp_path):
         """Docs mode prompt includes OpenAPI instructions."""
         eng = self._make_engineer(tmp_path, output_mode="docs")

tests/test_prompts.py

@@ -71,6 +71,17 @@ def test_typescript_partial(self):
         assert "TypeScript module" in text
         assert "interfaces" in text
 
+    def test_go_partial(self):
+        text = load_language_partial(
+            "go",
+            scripts_dir="/tmp/scripts",
+            client_filename="api_client.go",
+            run_command="go run api_client.go",
+        )
+        assert "Go program" in text
+        assert "net/http" in text
+        assert "/tmp/scripts/api_client.go" in text
+
 
 class TestEngineerTemplates:
     """Test engineer system/user templates."""