support responses api , support native message-api, fix inconsistent credit consumption in chat

.claude-plugin/marketplace.json

@@ -0,0 +1,13 @@
+{
+  "name": "copilot-api-marketplace",
+  "owner": {
+    "name": "copilot-api maintainers"
+  },
+  "plugins": [
+    {
+      "name": "claude-plugin",
+      "description": "Inject SubagentStart marker context for copilot-api initiator override",
+      "source": "./claude-plugin"
+    }
+  ]
+}

.opencode/plugins/subagent-marker.js

@@ -0,0 +1,78 @@
+const MARKER_PREFIX = "__SUBAGENT_MARKER__"
+
+const subagentSessions = new Set()
+const markedSessions = new Set()
+const sessionParentMap = new Map()
+
+const getSessionInfo = (event) => {
+  if (!event || typeof event !== "object") return undefined
+  const properties = event.properties
+  if (!properties || typeof properties !== "object") return undefined
+  const info = properties.info
+  if (!info || typeof info !== "object") return undefined
+  return info
+}
+
+export const SubagentMarkerPlugin = async () => {
+  return {
+    event: async ({ event }) => {
+      if (event.type === "session.created") {
+        const info = getSessionInfo(event)
+        if (info?.id) {
+          if (info.parentID) {
+            subagentSessions.add(info.id)
+            sessionParentMap.set(info.id, info.parentID)
+          } else {
+            sessionParentMap.set(info.id, info.id)
+          }
+        }
+        return
+      }
+
+      if (event.type === "session.deleted") {
+        const info = getSessionInfo(event)
+        if (info?.id) {
+          subagentSessions.delete(info.id)
+          markedSessions.delete(info.id)
+          sessionParentMap.delete(info.id)
+        }
+      }
+    },
+    "chat.message": async (input, output) => {
+      const { sessionID } = input
+      if (!subagentSessions.has(sessionID) || markedSessions.has(sessionID)) {
+        return
+      }
+      if (!output.message?.id || !output.message?.sessionID) {
+        return
+      }
+
+      const marker = `${MARKER_PREFIX}${JSON.stringify({
+        session_id: sessionID,
+        agent_id: sessionID,
+        agent_type: input.agent ?? "opencode-subagent",
+      })}`
+
+      output.parts.unshift({
+        id: `prt-${output.message.id}-subagent-marker`,
+        sessionID: output.message.sessionID,
+        messageID: output.message.id,
+        type: "text",
+        text: `<system-reminder>\nSubagentStart hook additional context: ${marker}\n</system-reminder>`,
+        synthetic: true,
+        time: {
+          start: Date.now(),
+          end: Date.now(),
+        },
+      })
+      markedSessions.add(sessionID)
+    },
+    "chat.headers": async (input, output) => {
+      const { sessionID } = input
+      const sessionIdValue = sessionParentMap.get(sessionID)
+      if (sessionIdValue) {
+        output.headers["x-session-id"] = sessionIdValue
+      }
+    },
+  }
+}

README.md

@@ -31,14 +31,17 @@ A reverse-engineered proxy for the GitHub Copilot API that exposes it as an Open
 
 ## Features
 
-- **OpenAI & Anthropic Compatibility**: Exposes GitHub Copilot as an OpenAI-compatible (`/v1/chat/completions`, `/v1/models`, `/v1/embeddings`) and Anthropic-compatible (`/v1/messages`) API.
+- **OpenAI & Anthropic Compatibility**: Exposes GitHub Copilot as an OpenAI-compatible (`/v1/responses`, `/v1/chat/completions`, `/v1/models`, `/v1/embeddings`) and Anthropic-compatible (`/v1/messages`) API.
 - **Claude Code Integration**: Easily configure and launch [Claude Code](https://docs.anthropic.com/en/docs/claude-code/overview) to use Copilot as its backend with a simple command-line flag (`--claude-code`).
 - **Usage Dashboard**: A web-based dashboard to monitor your Copilot API usage, view quotas, and see detailed statistics.
 - **Rate Limit Control**: Manage API usage with rate-limiting options (`--rate-limit`) and a waiting mechanism (`--wait`) to prevent errors from rapid requests.
 - **Manual Request Approval**: Manually approve or deny each API request for fine-grained control over usage (`--manual`).
 - **Token Visibility**: Option to display GitHub and Copilot tokens during authentication and refresh for debugging (`--show-token`).
 - **Flexible Authentication**: Authenticate interactively or provide a GitHub token directly, suitable for CI/CD environments.
 - **Support for Different Account Types**: Works with individual, business, and enterprise GitHub Copilot plans.
+- **Opencode OAuth Support**: Use opencode GitHub Copilot authentication by setting `COPILOT_API_OAUTH_APP=opencode` environment variable.
+- **GitHub Enterprise Support**: Connect to GHE.com by setting `COPILOT_API_ENTERPRISE_URL` environment variable (e.g., `company.ghe.com`).
+- **Custom Data Directory**: Change the default data directory (where tokens and config are stored) by setting `COPILOT_API_HOME` environment variable.
 
 ## Demo
 
@@ -177,6 +180,52 @@ The following command line options are available for the `start` command:
 | ------ | ------------------------- | ------- | ----- |
 | --json | Output debug info as JSON | false   | none  |
 
+## Configuration (config.json)
+
+- **Location:** `~/.local/share/copilot-api/config.json` (Linux/macOS) or `%USERPROFILE%\.local\share\copilot-api\config.json` (Windows).
+- **Default shape:**
+  ```json
+  {
+    "auth": {
+      "apiKeys": []
+    },
+    "extraPrompts": {
+      "gpt-5-mini": "<built-in exploration prompt>",
+      "gpt-5.1-codex-max": "<built-in exploration prompt>"
+    },
+    "smallModel": "gpt-5-mini",
+    "modelReasoningEfforts": {
+      "gpt-5-mini": "low"
+    },
+    "useFunctionApplyPatch": true,
+    "useMessagesApi": true
+  }
+  ```
+- **auth.apiKeys:** API keys used for request authentication. Supports multiple keys for rotation. Requests can authenticate with either `x-api-key: <key>` or `Authorization: Bearer <key>`. If empty or omitted, authentication is disabled.
+- **extraPrompts:** Map of `model -> prompt` appended to the first system prompt when translating Anthropic-style requests to Copilot. Use this to inject guardrails or guidance per model. Missing default entries are auto-added without overwriting your custom prompts.
+- **smallModel:** Fallback model used for tool-less warmup messages (e.g., Claude Code probe requests) to avoid spending premium requests; defaults to `gpt-5-mini`.
+- **modelReasoningEfforts:** Per-model `reasoning.effort` sent to the Copilot Responses API. Allowed values are `none`, `minimal`, `low`, `medium`, `high`, and `xhigh`. If a model isn’t listed, `high` is used by default.
+- **useFunctionApplyPatch:** When `true`, the server will convert any custom tool named `apply_patch` in Responses payloads into an OpenAI-style function tool (`type: "function"`) with a parameter schema so assistants can call it using function-calling semantics to edit files. Set to `false` to leave tools unchanged. Defaults to `true`.
+- **useMessagesApi:** When `true`, Claude-family models that support Copilot's native `/v1/messages` endpoint will use the Messages API; otherwise they fall back to `/chat/completions`. Set to `false` to disable Messages API routing and always use `/chat/completions`. Defaults to `true`.
+
+Edit this file to customize prompts or swap in your own fast model. Restart the server (or rerun the command) after changes so the cached config is refreshed.
+
+## API Authentication
+
+- **Protected routes:** All routes except `/` require authentication when `auth.apiKeys` is configured and non-empty.
+- **Allowed auth headers:**
+  - `x-api-key: <your_key>`
+  - `Authorization: Bearer <your_key>`
+- **CORS preflight:** `OPTIONS` requests are always allowed.
+- **When no keys are configured:** Server starts normally and allows requests (authentication disabled).
+
+Example request:
+
+```sh
+curl http://localhost:4141/v1/models \
+  -H "x-api-key: your_api_key"
+```
+
 ## API Endpoints
 
 The server exposes several endpoints to interact with the Copilot API. It provides OpenAI-compatible endpoints and now also includes support for Anthropic-compatible endpoints, allowing for greater flexibility with different tools and services.
@@ -185,11 +234,12 @@ The server exposes several endpoints to interact with the Copilot API. It provid
 
 These endpoints mimic the OpenAI API structure.
 
-| Endpoint                    | Method | Description                                               |
-| --------------------------- | ------ | --------------------------------------------------------- |
-| `POST /v1/chat/completions` | `POST` | Creates a model response for the given chat conversation. |
-| `GET /v1/models`            | `GET`  | Lists the currently available models.                     |
-| `POST /v1/embeddings`       | `POST` | Creates an embedding vector representing the input text.  |
+| Endpoint                    | Method | Description                                                      |
+| --------------------------- | ------ | ---------------------------------------------------------------- |
+| `POST /v1/responses`        | `POST` | OpenAI Most advanced interface for generating model responses.          |
+| `POST /v1/chat/completions` | `POST` | Creates a model response for the given chat conversation.        |
+| `GET /v1/models`            | `GET`  | Lists the currently available models.                            |
+| `POST /v1/embeddings`       | `POST` | Creates an embedding vector representing the input text.         |
 
 ### Anthropic Compatible Endpoints
 
@@ -255,6 +305,28 @@ npx copilot-api@latest debug --json
 
 # Initialize proxy from environment variables (HTTP_PROXY, HTTPS_PROXY, etc.)
 npx copilot-api@latest start --proxy-env
+
+# Use opencode GitHub Copilot authentication
+COPILOT_API_OAUTH_APP=opencode npx @jeffreycao/copilot-api@latest start
+```
+
+### Opencode OAuth Authentication
+
+You can use opencode GitHub Copilot authentication instead of the default one:
+
+```sh
+# Set environment variable before running any command
+export COPILOT_API_OAUTH_APP=opencode
+
+# Then run start or auth commands
+npx @jeffreycao/copilot-api@latest start
+npx @jeffreycao/copilot-api@latest auth
+```
+
+Or use inline environment variable:
+
+```sh
+COPILOT_API_OAUTH_APP=opencode npx @jeffreycao/copilot-api@latest start
 ```
 
 ## Using the Usage Viewer
@@ -307,12 +379,14 @@ Here is an example `.claude/settings.json` file:
   "env": {
     "ANTHROPIC_BASE_URL": "http://localhost:4141",
     "ANTHROPIC_AUTH_TOKEN": "dummy",
-    "ANTHROPIC_MODEL": "gpt-4.1",
-    "ANTHROPIC_DEFAULT_SONNET_MODEL": "gpt-4.1",
-    "ANTHROPIC_SMALL_FAST_MODEL": "gpt-4.1",
-    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "gpt-4.1",
+    "ANTHROPIC_MODEL": "gpt-5.2",
+    "ANTHROPIC_DEFAULT_SONNET_MODEL": "gpt-5.2",
+    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "gpt-5-mini",
     "DISABLE_NON_ESSENTIAL_MODEL_CALLS": "1",
-    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1"
+    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1",
+    "BASH_MAX_TIMEOUT_MS": "600000",
+    "CLAUDE_CODE_ATTRIBUTION_HEADER": "0",
+    "CLAUDE_CODE_ENABLE_PROMPT_SUGGESTION": "false"
   },
   "permissions": {
     "deny": [
@@ -326,6 +400,55 @@ You can find more options here: [Claude Code settings](https://docs.anthropic.co
 
 You can also read more about IDE integration here: [Add Claude Code to your IDE](https://docs.anthropic.com/en/docs/claude-code/ide-integrations)
 
+### Subagent Marker Integration (Optional)
+
+This project supports `x-initiator: agent` for subagent-originated requests.
+
+#### Claude Code plugin producer (marketplace-based)
+
+The marker producer is packaged as a Claude Code plugin named `claude-plugin`.
+
+- Marketplace catalog in this repository: `.claude-plugin/marketplace.json`
+- Plugin source in this repository: `claude-plugin`
+
+Add the marketplace remotely:
+
+```sh
+/plugin marketplace add https://github.com/ericc-ch/copilot-api.git
+```
+
+Install the plugin from the marketplace:
+
+```sh
+/plugin install claude-plugin@copilot-api-marketplace
+```
+
+After installation, the plugin injects `__SUBAGENT_MARKER__...` on `SubagentStart`, and this proxy uses it to infer `x-initiator: agent`.
+
+#### Opencode plugin producer
+
+The marker producer is packaged as an opencode plugin located at `.opencode/plugins/subagent-marker.js`.
+
+**Installation:**
+
+Copy the plugin file to your opencode plugins directory:
+
+```sh
+# Clone or download this repository, then copy the plugin
+cp .opencode/plugins/subagent-marker.js ~/.config/opencode/plugins/
+```
+
+Or manually create the file at `~/.config/opencode/plugins/subagent-marker.js` with the plugin content.
+
+**Features:**
+
+- Tracks sub-sessions created by subagents
+- Automatically prepends a marker system reminder (`__SUBAGENT_MARKER__...`) to subagent chat messages
+- Sets `x-session-id` header for session tracking
+- Enables this proxy to infer `x-initiator: agent` for subagent-originated requests
+
+The plugin hooks into `session.created`, `session.deleted`, `chat.message`, and `chat.headers` events to provide seamless subagent marker functionality.
+
 ## Running from Source
 
 The project can be run from source in several ways:
@@ -349,3 +472,10 @@ bun run start
   - `--rate-limit <seconds>`: Enforces a minimum time interval between requests. For example, `copilot-api start --rate-limit 30` will ensure there's at least a 30-second gap between requests.
   - `--wait`: Use this with `--rate-limit`. It makes the server wait for the cooldown period to end instead of rejecting the request with an error. This is useful for clients that don't automatically retry on rate limit errors.
 - If you have a GitHub business or enterprise plan account with Copilot, use the `--account-type` flag (e.g., `--account-type business`). See the [official documentation](https://docs.github.com/en/enterprise-cloud@latest/copilot/managing-copilot/managing-github-copilot-in-your-organization/managing-access-to-github-copilot-in-your-organization/managing-github-copilot-access-to-your-organizations-network#configuring-copilot-subscription-based-network-routing-for-your-enterprise-or-organization) for more details.
+
+### CLAUDE.md Recommended Content
+
+Please include the following in `CLAUDE.md` (for Claude usage):
+
+- Prohibited from directly asking questions to users, MUST use AskUserQuestion tool.
+- Once you can confirm that the task is complete, MUST use AskUserQuestion tool to make user confirm. The user may respond with feedback if they are not satisfied with the result, which you can use to make improvements and try again.

claude-plugin/.claude-plugin/plugin.json

@@ -0,0 +1,8 @@
+{
+  "name": "claude-plugin",
+  "description": "Inject SubagentStart marker context for copilot-api initiator override",
+  "version": "1.0.0",
+  "author": {
+    "name": "copilot-api maintainers"
+  }
+}

claude-plugin/hooks/hooks.json

@@ -0,0 +1,15 @@
+{
+  "hooks": {
+    "SubagentStart": [
+      {
+        "matcher": "*",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "node \"${CLAUDE_PLUGIN_ROOT}/scripts/subagent-start-marker.js\""
+          }
+        ]
+      }
+    ]
+  }
+}

claude-plugin/scripts/subagent-start-marker.js

@@ -0,0 +1,33 @@
+async function readStdin() {
+  let input = "";
+  for await (const chunk of process.stdin) {
+    input += chunk;
+  }
+  return input.trim();
+}
+
+const rawInput = await readStdin();
+let hookInput = {};
+
+if (rawInput) {
+  try {
+    hookInput = JSON.parse(rawInput);
+  } catch {
+    hookInput = {};
+  }
+}
+
+const marker = `__SUBAGENT_MARKER__${JSON.stringify({
+  session_id: hookInput.session_id ?? null,
+  agent_id: hookInput.agent_id ?? null,
+  agent_type: hookInput.agent_type ?? null,
+})}`;
+
+const payload = {
+  hookSpecificOutput: {
+    hookEventName: "SubagentStart",
+    additionalContext: marker,
+  },
+};
+
+process.stdout.write(`${JSON.stringify(payload)}\n`);

eslint.config.js

@@ -1,6 +1,7 @@
 import config from "@echristian/eslint-config"
 
 export default config({
+  ignores: ["claude-plugin/**", ".opencode/**"],
   prettier: {
     plugins: ["prettier-plugin-packagejson"],
   },