feat: make MailCLI Go-only and add config diagnostics

.github/ISSUE_TEMPLATE/bug_report.md

@@ -30,7 +30,7 @@ Describe the bug clearly.
 
 - OS:
 - Go version:
-- Python version (if examples are involved):
+- MailCLI version or commit:
 
 ## Evidence
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -8,7 +8,7 @@ Describe the change in 2-5 sentences.
 - [ ] Tests were added or updated where behavior changed
 - [ ] `go test ./...` passes locally
 - [ ] `go build ./cmd/mailcli` passes locally
-- [ ] Python examples still compile when touched
+- [ ] Go examples and demo artifacts were updated when touched
 - [ ] User-facing docs were updated when contracts or workflows changed
 - [ ] English and Chinese docs were both updated when needed
 

.github/workflows/test.yml

@@ -17,11 +17,6 @@ jobs:
         with:
           go-version-file: go.mod
 
-      - name: Setup Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: "3.x"
-
       - name: Run Go tests
         run: make test
 
@@ -30,7 +25,3 @@ jobs:
 
       - name: Check local thread demo artifacts
         run: make demo-local-thread-check
-
-      - name: Verify Python examples compile
-        run: |
-          python3 -m py_compile $(find examples/python -name '*.py' -print) $(find examples/providers -name '*.py' -print)

CONTRIBUTING.md

@@ -35,7 +35,8 @@ The goal is not to become a traditional terminal mail client. The goal is to bui
 ```bash
 go test ./...
 go build ./cmd/mailcli
-python3 -m py_compile examples/python/*.py examples/providers/*.py
+go test ./examples
+make demo-local-thread-check
 ```
 
 ## Pull Requests

CONTRIBUTING.zh-CN.md

@@ -35,7 +35,8 @@ MailCLI 是一个开源的 AI Native 邮件接口项目。
 ```bash
 go test ./...
 go build ./cmd/mailcli
-python3 -m py_compile examples/python/*.py examples/providers/*.py
+go test ./examples
+make demo-local-thread-check
 ```
 
 ## Pull Request 请包含

Makefile

@@ -13,15 +13,15 @@ test:
 	go test ./...
 
 demo-local-thread-refresh: build
-	PYTHONDONTWRITEBYTECODE=1 python3 examples/python/refresh_local_thread_demo.py \
+	go run ./examples/go/refresh_local_thread_demo \
 		--mailcli-bin $(MAILCLI_BIN) \
 		--config $(FIXTURES_CONFIG) \
 		--account $(FIXTURES_ACCOUNT) \
 		--index $(FIXTURES_INDEX) \
 		--output-dir $(LOCAL_THREAD_DEMO_DIR)
 
 demo-local-thread-check: build
-	PYTHONDONTWRITEBYTECODE=1 python3 examples/python/refresh_local_thread_demo.py \
+	go run ./examples/go/refresh_local_thread_demo \
 		--mailcli-bin $(MAILCLI_BIN) \
 		--config $(FIXTURES_CONFIG) \
 		--account $(FIXTURES_ACCOUNT) \

README.md

@@ -64,7 +64,7 @@ go build -o mailcli ./cmd/mailcli
 ./mailcli threads --index /tmp/mailcli-fixtures-index.db invoice
 
 # 3. inspect the full agent boundary
-python3 examples/python/agent_thread_assistant.py \
+go run ./examples/go/agent_thread_assistant \
   --mailcli-bin ./mailcli \
   --config examples/config/fixtures-dir.yaml \
   --account fixtures \
@@ -91,7 +91,7 @@ The repository already includes:
 
 - a local fixture corpus under `testdata/emails`
 - a zero-network config at `examples/config/fixtures-dir.yaml`
-- runnable Python examples
+- runnable Go examples under `examples/go`
 - a full local round-trip demo at [Local Thread Demo](docs/en/examples/local-thread-demo.md)
 - fixed outbound JSON and MIME pairs at [Outbound Draft Patterns](docs/en/examples/outbound-draft-patterns.md)
 
@@ -127,8 +127,8 @@ Working today:
 - delete, move, mark-read/unread on remote mailboxes
 - export the local index as JSONL, JSON, or CSV
 - **watch** one or more mailboxes with IMAP IDLE push (streaming JSONL event feed, persistent seen state across restarts)
-- manage config with `mailcli config show` / `mailcli config test`
-- integrate with Python or shell agent workflows through stable JSON contracts
+- create, inspect, diagnose, test, and inspect account capabilities with `mailcli config init` / `mailcli config show` / `mailcli config doctor` / `mailcli config test` / `mailcli config capabilities`
+- integrate with Go, shell, and external agent workflows through stable JSON contracts
 - LLM tool-use schemas for OpenAI and Anthropic (`tools/` directory)
 
 Stable enough to build against for `v0.1 RC`:
@@ -147,7 +147,7 @@ Stable enough to build against for `v0.1 RC`:
 - `mailcli mark`
 - `mailcli export`
 - `mailcli watch`
-- `mailcli config show|test`
+- `mailcli config init|show|doctor|test|capabilities`
 - `StandardMessage`
 - `DraftMessage`
 - `ReplyDraft`
@@ -268,13 +268,18 @@ MailCLI solves that by providing a stable boundary:
   ```bash
   # Pipe to AI agent with persistent deduplication:
   mailcli watch --account work --index ~/.config/mailcli/index.db \
-    | python3 tools/agent_example.py
+    | go run ./examples/go/watch_reply_agent --from-address support@nono.im
   ```
 
 ### Config management
 
+- `mailcli config init [--config] --account <name> --driver imap --host <host> --username <email> --password-env <ENV>` — create a starter config file that stores secret environment references such as `${MAILCLI_IMAP_PASSWORD}`, not raw passwords
 - `mailcli config show [--config]` — print accounts (passwords redacted)
+- `mailcli config doctor [--config]` — run local static diagnostics without connecting to IMAP or SMTP
 - `mailcli config test [--config] [--account]` — test live connection
+- `mailcli config capabilities [--config] [--account]` — print machine-readable account capabilities without connecting to the mailbox server
+
+`config init`, `config doctor`, and `config capabilities` are safe onboarding commands for agents and setup scripts. They do not print configured password values. `config doctor` distinguishes missing secret references from unset environment variables such as `imap_password_env_unset`. `config test` is the command that performs a live mailbox connection check.
 
 ### Outbound Markdown baseline
 
@@ -461,7 +466,7 @@ cat test.eml | mailcli parse --format json -
 If you want the full agent-side JSON and reply boundary, use:
 
 ```bash
-python3 examples/python/agent_thread_assistant.py \
+go run ./examples/go/agent_thread_assistant \
   --mailcli-bin ./mailcli \
   --config examples/config/fixtures-dir.yaml \
   --account fixtures \
@@ -470,7 +475,7 @@ python3 examples/python/agent_thread_assistant.py \
   --query invoice
 ```
 
-If you want fixed JSON and MIME pairs for outbound composition without reading Python code, use:
+If you want fixed JSON and MIME pairs for outbound composition without reading example code, use:
 
 ```bash
 ./mailcli reply --config examples/config/fixtures-dir.yaml --account fixtures --dry-run examples/artifacts/outbound-patterns/ack-reply.draft.json
@@ -561,15 +566,15 @@ mailcli reply --dry-run reply.json
 ### Run the agent example
 
 ```bash
-python3 examples/python/agent_inbox_assistant.py \
+go run ./examples/go/agent_inbox_assistant \
   --mailcli-bin ./mailcli \
   --email testdata/emails/verification.eml
 ```
 
 ### Run the thread agent example
 
 ```bash
-python3 examples/python/agent_thread_assistant.py \
+go run ./examples/go/agent_thread_assistant \
   --mailcli-bin ./mailcli \
   --config ~/.config/mailcli/config.yaml \
   --account work \

README.zh-CN.md

@@ -64,7 +64,7 @@ go build -o mailcli ./cmd/mailcli
 ./mailcli threads --index /tmp/mailcli-fixtures-index.db invoice
 
 # 3. 查看完整的 agent 边界
-python3 examples/python/agent_thread_assistant.py \
+go run ./examples/go/agent_thread_assistant \
   --mailcli-bin ./mailcli \
   --config examples/config/fixtures-dir.yaml \
   --account fixtures \
@@ -91,7 +91,7 @@ flowchart LR
 
 - `testdata/emails` 下的本地 fixture 语料
 - 零网络配置 `examples/config/fixtures-dir.yaml`
-- 可直接运行的 Python 示例
+- `examples/go` 下可直接运行的 Go 示例
 - 一份完整的本地往返说明：[Local Thread Demo](docs/zh-CN/examples/local-thread-demo.md)
 - 一组固定的出站 JSON / MIME 对照样例：[Outbound Draft Patterns](docs/zh-CN/examples/outbound-draft-patterns.md)
 
@@ -127,8 +127,8 @@ MailCLI 当前处于 **pre-v0.1 release candidate** 阶段。
 - 删除、移动、读/未读标记远端邮件
 - 将本地索引导出为 JSONL、JSON 或 CSV
 - **watch** 一个或多个邮箱（IMAP IDLE 推送事件流，重启后持久化去重）
-- `mailcli config show` / `mailcli config test` 管理配置
-- 通过稳定 JSON 契约与 Python / shell agent 工作流协作
+- `mailcli config init` / `mailcli config show` / `mailcli config doctor` / `mailcli config test` / `mailcli config capabilities` 创建、查看、诊断、测试配置与账户能力
+- 通过稳定 JSON 契约与 Go、shell 和外部 agent 工作流协作
 - OpenAI 和 Anthropic 格式的 LLM Tool Use Schema（`tools/` 目录）
 
 在 `v0.1 RC` 阶段，已经足够作为稳定集成边界的部分：
@@ -147,7 +147,7 @@ MailCLI 当前处于 **pre-v0.1 release candidate** 阶段。
 - `mailcli mark`
 - `mailcli export`
 - `mailcli watch`
-- `mailcli config show|test`
+- `mailcli config init|show|doctor|test|capabilities`
 - `StandardMessage`
 - `DraftMessage`
 - `ReplyDraft`
@@ -254,6 +254,16 @@ MailCLI 提供的是一个稳定边界：
 - `mailcli reply --dry-run <reply.json>`
 - `mailcli reply --config ~/.config/mailcli/config.yaml <reply.json>`
 
+### 配置与能力发现
+
+- `mailcli config init [--config] --account <name> --driver imap --host <host> --username <email> --password-env <ENV>`
+- `mailcli config show [--config]`
+- `mailcli config doctor [--config]`
+- `mailcli config test [--config] [--account]`
+- `mailcli config capabilities [--config] [--account]`
+
+`config init` 会生成 starter YAML，并把秘密值写成 `${MAILCLI_IMAP_PASSWORD}` 这样的环境变量引用，而不是原始密码。`config doctor` 做本地静态诊断，不连接 IMAP / SMTP，并能区分“没有写 secret 引用”和“引用存在但环境变量未设置”，例如 `imap_password_env_unset`。`config capabilities` 输出稳定 JSON，帮助 Agent 在执行 `send`、`watch`、`delete` 等命令前判断当前账户能力。它只读取本地配置和内置 driver 的已知能力，不连接邮箱服务器，也不输出密码。真正联网检查连接的是 `config test`。
+
 ### 出站 Markdown 基线
 
 - 标题
@@ -438,7 +448,7 @@ cat test.eml | mailcli parse --format json -
 如果你想直接看 agent 侧完整 JSON 和 reply 边界，可以运行：
 
 ```bash
-python3 examples/python/agent_thread_assistant.py \
+go run ./examples/go/agent_thread_assistant \
   --mailcli-bin ./mailcli \
   --config examples/config/fixtures-dir.yaml \
   --account fixtures \
@@ -447,7 +457,7 @@ python3 examples/python/agent_thread_assistant.py \
   --query invoice
 ```
 
-如果你想在不读 Python 示例的情况下直接查看固定的出站 JSON / MIME 对照，可以运行：
+如果你想在不读示例代码的情况下直接查看固定的出站 JSON / MIME 对照，可以运行：
 
 ```bash
 ./mailcli reply --config examples/config/fixtures-dir.yaml --account fixtures --dry-run examples/artifacts/outbound-patterns/ack-reply.draft.json
@@ -538,15 +548,15 @@ mailcli reply --dry-run reply.json
 ### 运行 agent 示例
 
 ```bash
-python3 examples/python/agent_inbox_assistant.py \
+go run ./examples/go/agent_inbox_assistant \
   --mailcli-bin ./mailcli \
   --email testdata/emails/verification.eml
 ```
 
 ### 运行 thread agent 示例
 
 ```bash
-python3 examples/python/agent_thread_assistant.py \
+go run ./examples/go/agent_thread_assistant \
   --mailcli-bin ./mailcli \
   --config ~/.config/mailcli/config.yaml \
   --account work \