Add Ruby as a supported output language

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Java output language**: `output_language: "java"` is now supported alongside python/javascript/typescript, generating a small Maven project using `java.net.http.HttpClient` (JDK 11+, no HTTP library dependency) and Gson for JSON, with the same auth-hardcoding/refresh guidance as the other languages.
 - **C# output language**: `output_language: "csharp"` is now supported alongside python/javascript/typescript, generating a minimal .NET project using `System.Net.Http.HttpClient` and `System.Text.Json` (both part of the .NET 5+ base class library — no NuGet dependency needed), with the same auth-hardcoding/refresh guidance as the other languages.
 - **PHP output language**: `output_language: "php"` is now supported alongside python/javascript/typescript, generating a script using the `curl` and `json_encode`/`json_decode` core extensions (`ext-curl`, `ext-json` — no Composer dependency needed), with the same auth-hardcoding/refresh guidance as the other languages.
+- **Ruby output language**: `output_language: "ruby"` is now supported alongside python/javascript/typescript, generating a script using `net/http` and `json` (both part of Ruby's standard library — no gem/Bundler dependency needed), with the same auth-hardcoding/refresh guidance as the other languages.
 
 ## [0.10.0] - 2026-06-01
 

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`, `typescript`, `go`, `java`, `csharp`, or `php`.
+- **Output language**: `python`, `javascript`, `typescript`, `go`, `java`, `csharp`, `php`, or `ruby`.
 
 ## CLI
 

src/reverse_api/base_engineer.py

@@ -38,6 +38,7 @@ class BaseEngineer(ABC):
         "java": ".java",
         "csharp": ".cs",
         "php": ".php",
+        "ruby": ".rb",
     }
 
     def __init__(
@@ -448,6 +449,7 @@ def _get_language_name(self) -> str:
             "java": "Java",
             "csharp": "C#",
             "php": "PHP",
+            "ruby": "Ruby",
         }.get(self.output_language, "Python")
 
     def _get_existing_client_guidance(self) -> str:
@@ -530,6 +532,20 @@ def _get_run_command(self) -> str:
             # pointing this command at the wrong, doubly-nested location.
             path = shlex.quote(str(self.scripts_dir.resolve() / self._get_client_filename()))
             return f"php {path}"
+        if self.output_language == "ruby":
+            # Full path, not a bare relative "ruby api_client.rb": the
+            # agent's cwd for the whole session is scripts_dir.parent.parent
+            # (see analyze_and_generate's ClaudeAgentOptions), not
+            # scripts_dir itself where the script is actually saved — the
+            # same working-directory ambiguity fixed for Go/Java/C#/PHP.
+            # shlex.quote (not manual double-quoting) so shell metacharacters
+            # in the path can't be interpreted as command substitution.
+            # .resolve(): a relative --output-dir would otherwise be
+            # re-interpreted against the agent's cwd (scripts_dir.parent.
+            # parent) instead of the original cwd it was relative to,
+            # pointing this command at the wrong, doubly-nested location.
+            path = shlex.quote(str(self.scripts_dir.resolve() / self._get_client_filename()))
+            return f"ruby {path}"
         return {
             "python": "python api_client.py",
             "javascript": "node api_client.js",

src/reverse_api/cli.py

@@ -1087,6 +1087,7 @@ def handle_settings(mode_color=THEME_PRIMARY):
             Choice(title="java", value="java"),
             Choice(title="csharp", value="csharp"),
             Choice(title="php", value="php"),
+            Choice(title="ruby", value="ruby"),
             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", "typescript", "go", "java", "csharp", or "php"
+    "output_language": "python",  # "python", "javascript", "typescript", "go", "java", "csharp", "php", or "ruby"
     "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", "typescript", "go", "java", "csharp", or "php"
+        output_language: Target language - "python", "javascript", "typescript", "go", "java", "csharp", "php", or "ruby"
         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", "go", "java", "csharp", "php".
+        language: One of "python", "javascript", "typescript", "go", "java", "csharp", "php", "ruby".
         **kwargs: Placeholder values (scripts_dir, client_filename, run_command).
     """
     return load(f"partials/_language_{language}", **kwargs)

src/reverse_api/prompts/partials/_language_ruby.md

@@ -0,0 +1,20 @@
+**Generate a Ruby script** that replicates the API calls found in the traffic. The following are guidelines — use your judgment on what's appropriate for the specific API:
+
+- Use `net/http` and `json` for requests and JSON — both are part of Ruby's standard library, so no gem/Bundler dependency is needed
+- Reuse persistent connections (`Net::HTTP.start` held open across calls) rather than opening a new connection per request — use a separate connection per distinct scheme/host/port, since one is bound to a single origin and captured traffic may span several (e.g. separate login, API, and upload hosts)
+- Create a separate method for each distinct API endpoint
+- Include example usage at the bottom of the script
+
+**Authentication & credentials:**
+- Hardcode all cookies, tokens, session IDs, and auth headers found in the traffic directly in the script
+- The user should be able to run the script immediately with zero configuration — no env vars, no config files, no `bundle install`
+- `net/http` has no built-in cookie jar, unlike some other languages' HTTP clients — if the API uses cookies, store each `Set-Cookie` header by name, domain, and path; enforce its secure, `Expires`, and `Max-Age` attributes; remove expired or deleted entries; and send back only cookies matching the request's origin and path in the `Cookie` header (a multi-origin trace can otherwise leak a session cookie to the wrong host or send an invalid header)
+- If the API uses Bearer tokens or API keys, hardcode them in the request headers
+- Handle auth refresh so the script 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:**
+- Run: `{run_command}`
+- You have up to 5 attempts to fix issues
+
+Save the script to: `{scripts_dir}/{client_filename}`
+Save documentation to: `{scripts_dir}/README.md`

tests/test_base_engineer.py

@@ -210,6 +210,10 @@ def test_get_output_extension_php(self, tmp_path):
         """PHP extension."""
         eng = self._make_engineer(tmp_path, output_language="php")
         assert eng._get_output_extension() == ".php"
+    def test_get_output_extension_ruby(self, tmp_path):
+        """Ruby extension."""
+        eng = self._make_engineer(tmp_path, output_language="ruby")
+        assert eng._get_output_extension() == ".rb"
 
     def test_get_output_extension_unknown(self, tmp_path):
         """Unknown language defaults to .py."""
@@ -343,6 +347,37 @@ def test_get_run_command_php_resolves_relative_output_dir(self, tmp_path):
         script_arg = tokens[1]
         assert Path(script_arg).is_absolute()
         assert script_arg == str(eng.scripts_dir.resolve() / "api_client.php")
+    def test_get_run_command_ruby(self, tmp_path):
+        """Run command for Ruby uses the full, resolved, shell-quoted path,
+        not a bare relative filename — the agent's cwd is scripts_dir.
+        parent.parent (see analyze_and_generate), not scripts_dir where the
+        script lives."""
+        eng = self._make_engineer(tmp_path, output_language="ruby")
+        expected_path = shlex.quote(str(eng.scripts_dir.resolve() / "api_client.rb"))
+        assert eng._get_run_command() == f"ruby {expected_path}"
+
+    def test_get_run_command_ruby_quotes_metacharacters(self, tmp_path):
+        """A scripts_dir containing shell metacharacters must round-trip
+        back to the literal path, not be left open to $()/backtick
+        expansion — what the naive f'"{path}"' approach got wrong."""
+        eng = self._make_engineer(tmp_path, output_language="ruby")
+        eng.scripts_dir = Path("/tmp/weird$(rm -rf ~) dir")
+        tokens = shlex.split(eng._get_run_command())
+        assert tokens[0] == "ruby"
+        assert tokens[1] == str(eng.scripts_dir.resolve() / "api_client.rb")
+
+    def test_get_run_command_ruby_resolves_relative_output_dir(self, tmp_path):
+        """A relative scripts_dir must be resolved to an absolute path before
+        being embedded in the command — otherwise, once the agent's cwd
+        moves to scripts_dir.parent.parent, the same relative string gets
+        re-interpreted from there and points at the wrong, doubly-nested
+        location."""
+        eng = self._make_engineer(tmp_path, output_language="ruby")
+        eng.scripts_dir = Path("relative_output/scripts/run123")
+        tokens = shlex.split(eng._get_run_command())
+        script_arg = tokens[1]
+        assert Path(script_arg).is_absolute()
+        assert script_arg == str(eng.scripts_dir.resolve() / "api_client.rb")
 
     def test_get_run_command_unknown(self, tmp_path):
         """Unknown language defaults to Python command."""
@@ -413,6 +448,12 @@ def test_php_prompt(self, tmp_path):
         system_prompt, user_message = eng._build_prompts()
         assert "PHP script" in system_prompt
         assert "curl" in system_prompt
+    def test_ruby_prompt(self, tmp_path):
+        """Ruby prompt includes Ruby-specific instructions."""
+        eng = self._make_engineer(tmp_path, output_language="ruby")
+        system_prompt, user_message = eng._build_prompts()
+        assert "Ruby script" in system_prompt
+        assert "net/http" in system_prompt
 
     def test_docs_prompt(self, tmp_path):
         """Docs mode prompt includes OpenAPI instructions."""

tests/test_prompts.py

@@ -111,6 +111,16 @@ def test_php_partial(self):
         assert "PHP script" in text
         assert "curl" in text
         assert "/tmp/scripts/api_client.php" in text
+    def test_ruby_partial(self):
+        text = load_language_partial(
+            "ruby",
+            scripts_dir="/tmp/scripts",
+            client_filename="api_client.rb",
+            run_command='ruby "/tmp/scripts/api_client.rb"',
+        )
+        assert "Ruby script" in text
+        assert "net/http" in text
+        assert "/tmp/scripts/api_client.rb" in text
 
 
 class TestEngineerTemplates: