expose openai_responses API style to C and Go bindings

2 files changed, 8 insertions, 7 deletions

diff --git a/libpanto-c/include/panto.h b/libpanto-c/include/panto.h
index 5457715..4302bb8 100644
--- a/libpanto-c/include/panto.h
+++ b/libpanto-c/include/panto.h
@@ -25,7 +25,7 @@ typedef struct { const uint8_t *ptr; size_t len; } PantoSlice;
 
 typedef enum { PANTO_OK = 0, PANTO_ERROR = 1 } PantoStatus;
 typedef enum { PANTO_NEXT_EVENT = 0, PANTO_NEXT_DONE = 1, PANTO_NEXT_ERROR = 2 } PantoNextStatus;
-typedef enum { PANTO_OPENAI_CHAT = 0, PANTO_ANTHROPIC_MESSAGES = 1 } PantoAPIStyle;
+typedef enum { PANTO_OPENAI_CHAT = 0, PANTO_ANTHROPIC_MESSAGES = 1, PANTO_OPENAI_RESPONSES = 2, PANTO_OPENAI_CODEX_RESPONSES = 3 } PantoAPIStyle;
 typedef enum { PANTO_REASONING_DEFAULT = 0, PANTO_REASONING_OFF, PANTO_REASONING_MINIMAL, PANTO_REASONING_LOW, PANTO_REASONING_MEDIUM, PANTO_REASONING_HIGH } PantoReasoningEffort;
 typedef enum { PANTO_THINKING_DISABLED = 0, PANTO_THINKING_ENABLED, PANTO_THINKING_ADAPTIVE } PantoThinking;
 typedef enum { PANTO_EFFORT_LOW = 0, PANTO_EFFORT_MEDIUM, PANTO_EFFORT_HIGH, PANTO_EFFORT_XHIGH, PANTO_EFFORT_MAX } PantoEffort;
@@ -40,8 +40,9 @@ typedef struct { PantoSlice id, created, modified, last_user_message, base_url,
 typedef struct { PantoSessionInfo *ptr; size_t len; } PantoSessionInfoList;
 typedef struct { bool found; PantoSession *session; } PantoSessionResult;
 typedef struct { const char *api_key, *base_url, *model; PantoReasoningEffort reasoning; uint32_t max_tokens; } PantoOpenAIChatConfig;
+typedef struct { const char *api_key, *base_url, *model; PantoReasoningEffort reasoning; uint32_t max_tokens; } PantoOpenAIResponsesConfig;
 typedef struct { const char *api_key, *base_url, *model, *api_version; uint32_t max_tokens; PantoThinking thinking; PantoEffort effort; bool has_thinking_budget_tokens; uint32_t thinking_budget_tokens; bool thinking_interleaved; } PantoAnthropicMessagesConfig;
-typedef struct { PantoAPIStyle tag; union { PantoOpenAIChatConfig openai_chat; PantoAnthropicMessagesConfig anthropic_messages; } data; } PantoProviderConfig;
+typedef struct { PantoAPIStyle tag; union { PantoOpenAIChatConfig openai_chat; PantoAnthropicMessagesConfig anthropic_messages; PantoOpenAIResponsesConfig openai_responses; } data; } PantoProviderConfig;
 typedef struct { uint32_t keep_verbatim; bool has_model; PantoProviderConfig model; bool has_compaction_prompt; const char *compaction_prompt; } PantoCompactionConfig;
 typedef struct { size_t max_attempts; uint64_t initial_delay_ms, max_delay_ms; double multiplier; bool jitter; } PantoRetryConfig;
 typedef struct { PantoProviderConfig provider; PantoCompactionConfig compaction; PantoRetryConfig retry; } PantoConfig;
diff --git a/libpanto-c/src/lib.zig b/libpanto-c/src/lib.zig
index 7f61ae3..4fcf94b 100644
--- a/libpanto-c/src/lib.zig
+++ b/libpanto-c/src/lib.zig
@@ -26,7 +26,7 @@ const MessageBuilder = struct { role: panto.MessageRole, blocks: std.ArrayList(p
 pub const PantoSlice = extern struct { ptr: ?[*]const u8, len: usize };
 pub const PantoStatus = enum(c_int) { ok = 0, err = 1 };
 pub const PantoNextStatus = enum(c_int) { event = 0, done = 1, err = 2 };
-pub const PantoAPIStyle = enum(c_int) { openai_chat = 0, anthropic_messages = 1 };
+pub const PantoAPIStyle = enum(c_int) { openai_chat = 0, anthropic_messages = 1, openai_responses = 2, openai_codex_responses = 3 };
 pub const PantoReasoningEffort = enum(c_int) { default = 0, off, minimal, low, medium, high };
 pub const PantoThinking = enum(c_int) { disabled = 0, enabled, adaptive };
 pub const PantoEffort = enum(c_int) { low = 0, medium, high, xhigh, max };
@@ -40,8 +40,9 @@ pub const PantoSessionInfo = extern struct { id: PantoSlice, created: PantoSlice
 pub const PantoSessionInfoList = extern struct { ptr: ?[*]PantoSessionInfo, len: usize };
 pub const PantoSessionResult = extern struct { found: bool, session: ?*PantoSession };
 pub const PantoOpenAIChatConfig = extern struct { api_key: ?[*:0]const u8, base_url: ?[*:0]const u8, model: ?[*:0]const u8, reasoning: PantoReasoningEffort, max_tokens: u32 };
+pub const PantoOpenAIResponsesConfig = extern struct { api_key: ?[*:0]const u8, base_url: ?[*:0]const u8, model: ?[*:0]const u8, reasoning: PantoReasoningEffort, max_tokens: u32 };
 pub const PantoAnthropicMessagesConfig = extern struct { api_key: ?[*:0]const u8, base_url: ?[*:0]const u8, model: ?[*:0]const u8, api_version: ?[*:0]const u8, max_tokens: u32, thinking: PantoThinking, effort: PantoEffort, has_thinking_budget_tokens: bool, thinking_budget_tokens: u32, thinking_interleaved: bool };
-pub const PantoProviderConfig = extern struct { tag: PantoAPIStyle, data: extern union { openai_chat: PantoOpenAIChatConfig, anthropic_messages: PantoAnthropicMessagesConfig } };
+pub const PantoProviderConfig = extern struct { tag: PantoAPIStyle, data: extern union { openai_chat: PantoOpenAIChatConfig, anthropic_messages: PantoAnthropicMessagesConfig, openai_responses: PantoOpenAIResponsesConfig } };
 pub const PantoCompactionConfig = extern struct { keep_verbatim: u32, has_model: bool, model: PantoProviderConfig, has_compaction_prompt: bool, compaction_prompt: ?[*:0]const u8 };
 pub const PantoRetryConfig = extern struct { max_attempts: usize, initial_delay_ms: u64, max_delay_ms: u64, multiplier: f64, jitter: bool };
 pub const PantoConfig = extern struct { provider: PantoProviderConfig, compaction: PantoCompactionConfig, retry: PantoRetryConfig };
@@ -485,6 +486,8 @@ fn convertProvider(p: PantoProviderConfig) !panto.ProviderConfig {
     return switch (p.tag) {
         .openai_chat => .{ .openai_chat = .{ .api_key = try dupCStr(p.data.openai_chat.api_key), .base_url = try dupCStr(p.data.openai_chat.base_url), .model = try dupCStr(p.data.openai_chat.model), .reasoning = @enumFromInt(@intFromEnum(p.data.openai_chat.reasoning)), .max_tokens = p.data.openai_chat.max_tokens } },
         .anthropic_messages => .{ .anthropic_messages = .{ .api_key = try dupCStr(p.data.anthropic_messages.api_key), .base_url = try dupCStr(p.data.anthropic_messages.base_url), .model = try dupCStr(p.data.anthropic_messages.model), .api_version = if (cstr(p.data.anthropic_messages.api_version).len == 0) "2023-06-01" else try dupCStr(p.data.anthropic_messages.api_version), .max_tokens = p.data.anthropic_messages.max_tokens, .thinking = @enumFromInt(@intFromEnum(p.data.anthropic_messages.thinking)), .effort = @enumFromInt(@intFromEnum(p.data.anthropic_messages.effort)), .thinking_budget_tokens = if (p.data.anthropic_messages.has_thinking_budget_tokens) p.data.anthropic_messages.thinking_budget_tokens else null, .thinking_interleaved = p.data.anthropic_messages.thinking_interleaved } },
+        .openai_responses => .{ .openai_responses = .{ .api_key = try dupCStr(p.data.openai_responses.api_key), .base_url = try dupCStr(p.data.openai_responses.base_url), .model = try dupCStr(p.data.openai_responses.model), .reasoning = @enumFromInt(@intFromEnum(p.data.openai_responses.reasoning)), .max_tokens = p.data.openai_responses.max_tokens } },
+        .openai_codex_responses => return error.UnsupportedProvider,
     };
 }
 fn freeConfig(c: *panto.Config) void {
@@ -506,9 +509,6 @@ fn freeProvider(pv: *panto.ProviderConfig) void {
             allocator.free(c.model);
             if (c.api_version.ptr != "2023-06-01".ptr) allocator.free(c.api_version);
         },
-        // The Responses styles are not constructible across the C ABI (no
-        // PantoAPIStyle variant), so `convertProvider` never builds them; these
-        // cases exist only to keep the union switch exhaustive.
         .openai_responses, .openai_codex_responses => |c| {
             allocator.free(c.api_key);
             allocator.free(c.base_url);