Initial commit

Co-authored-by: xinchengxx <xinchengxx@deepseek.com>
Co-authored-by: XieJiSS <xiejiss@deepseek.com>
Co-authored-by: yqaty <jiayu@deepseek.com>
Co-authored-by: zhu-he <hezhu@deepseek.com>
Co-authored-by: season-guo <seasonguo@deepseek.com>

encoding-decoding-demo/README.md

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+# Encoding & Decoding Demo
+
+A web interface for rendering DeepSeek V4.1 prompts, inspecting special tokens,
+and decoding complete model output into Chat Completions, Responses, and Messages
+API formats.
+
+## Usage
+
+Use the Rust toolchain pinned in the repository and a C/C++ compiler. This
+example does not require OpenCV, model weights, or an API key. From the
+repository root:
+
+```sh
+cargo run -p encoding-decoding-demo --locked
+```
+
+Open [http://127.0.0.1:7778](http://127.0.0.1:7778). Set `DEMO_ADDR` to change the
+listening address.
+
+Use the Encode / Decode buttons to switch between modes; only the selected
+mode's editor and result are shown. In Encode mode, select an API format, edit
+its request JSON, and render the request to inspect the model prompt. In Decode
+mode, edit the complete assistant output and decode it. Model output is
+rendered with the same special-token highlights as the prompt. Switching modes or
+formats keeps each request draft and reuses the same model output.
+
+The example output includes `<think>…</think>` reasoning, answer text, two DSML
+weather tool calls (Beijing and Shanghai, each with string and numeric
+arguments), and the end-of-turn marker `<｜end▁of▁sentence｜>`. Each protocol's
+sample request declares the weather tool and includes the preceding tool
+result and follow-up question.
+
+The decoded JSON view shows only response content, reasoning, and tool calls.
+It omits finish status and server-generated metadata such as response
+and tool-call IDs, model names, timestamps, token usage, and thinking
+signatures. Tool inputs and arguments remain intact, including payload fields
+with those names. The HTTP endpoint still returns the complete protocol
+response.
+
+The decoder accepts complete assistant content, including the opening
+`<think>` when reasoning is present, and an optional leading `<｜Assistant｜>`.
+It consumes these frame markers before passing the content to the library's
+stream parser. Output without an opening `<think>` is answer content; a
+leading `</think>` from a non-thinking assistant prefix is also accepted.
+Parsing starts outside tool-call markup because the complete output includes
+its DSML opening block. Tool declarations, JSON output mode, and stop sequences
+come from the selected protocol request.
+
+Edit the model output, then use the adjacent decode button or Cmd/Ctrl+Enter. The UI
+uses the default `stop` finish reason without displaying protocol status. If
+the pasted output contains `<｜end▁of▁sentence｜>`, the demo treats its first
+occurrence as EOS and discards that marker and everything after it.
+
+## HTTP endpoints
+
+`POST /api/render` accepts `{ "format": "…", "body": { … } }` and returns the
+prompt with highlighted segments.
+
+`POST /api/decode` accepts the same request plus `output` and an optional
+`finish_reason` (default: `stop`). The formats are `chat_completions`,
+`responses`, and `messages`. For example:
+
+```sh
+curl http://127.0.0.1:7778/api/decode \
+  -H 'content-type: application/json' \
+  -d '{
+    "format": "chat_completions",
+    "body": {"messages": [{"role": "user", "content": "Hello"}]},
+    "output": "<think>Respond in English.</think>Hello!<｜end▁of▁sentence｜>",
+    "finish_reason": "stop"
+  }'
+```
+
+The result is `{ "response": { … }, "segments": [ … ] }`. `segments` preserves
+the complete supplied model output for highlighting, including its frame
+markers. `response` is the complete protocol response, even when the input
+request sets `stream: true`. The demo
+uses the supplied model name or `encoding-decoding-demo`, a demonstration response ID,
+and zero token usage because no tokenizer or backend usage data is supplied.
+Decoding uses the library's stream parser and protocol response accumulators.
+API callers can supply `length` or `content_filter` as the backend finish
+reason. EOS uses `stop` instead, and matched request stop sequences take
+precedence.
+
+This example has no authentication. Keep the default loopback address for local
+use. It renders prompts and decodes supplied text; it does not execute
+inference, run tools, or fetch image URLs.