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AIBridge Python v1 → v2 Migration Guide

This guide helps existing agn-sdk (v1, Python) users migrate smoothly to aibridge (v2, Rust core + five-language bindings). v2 is a breaking upgrade (semver v2.0.0). The API style changes, but capabilities, providers, and method names remain largely consistent. Target audience: existing projects migrating Python code from agn-sdk to aibridge.


1. Why Migrate

Dimension v1 (agn-sdk) v2 (aibridge)
Implementation language Python (~19,700 lines) Rust core + five-language native bindings
Supported languages Python only Python / JS-TS / Go / JVM / .NET
Performance Native Python Rust (no GIL, native async, zero-cost abstractions)
Type safety Pydantic + **kwargs serde struct + Builder (compile-time guarantees)
Number of providers 38 38 (full migration, zero loss)
Brand agn-sdk aibridge

Migration benefits: one API shared across five languages; a faster and more stable Rust core; explicit structs replacing **kwargs, with better IDE completion and compile-time checks.

Migration cost: mainly mechanical replacement of package names, error class names, and parameter-passing styles. Method names and capabilities are largely unchanged, so business logic needs no rewrite.


2. Quick Reference (One-Page Change Overview)

Change point v1 (agn-sdk) v2 (aibridge) Impact
Package name agn-sdk aibridge pip install aibridge
Import from agn import Client from aibridge import Client Change import
Error base class AGNError AibridgeError Change exception class name
Error subclass names RateLimitError, etc. RateLimitError, etc. Unchanged
Error code RATE_LIMIT_ERROR (uppercase) rate_limit_error (snake_case) Change needed if parsing code
Parameter passing **kwargs + ChatOptions Request struct + Builder Change call style
Options intermediate layer ChatOptions/ImageOptions/... Removed, use builder directly Remove Options
Streaming entry point chat(stream=True) chat_stream(req) as a separate method Split into two methods
Translation client.translate(...) transcribe(req, translate=true) Merged into transcribe
Method names chat/image_generate/... Unchanged
Provider names openai/agnes/... Unchanged (aliases also preserved)
Environment variables AGN_API_KEY AIBRIDGE_API_KEY (compatible with legacy AGN_*) Optional

3. Package Name and Import

v1

# Install: pip install agn-sdk
from agn import Client, Router
from agn import AGNError, RateLimitError, ValidationError
from agn import ChatOptions, ImageOptions, SpeechOptions

v2

# Install: pip install aibridge
from aibridge import Client
from aibridge import AibridgeError, RateLimitError, ValidationError

v2 removes the Options intermediate layer and no longer exports ChatOptions/ImageOptions/.... Router is already implemented in the Rust core; the Python binding will expose it in future releases.


4. Error Class Mapping

The error taxonomy is completely identical; only the base class is renamed and the code format is adjusted. Subclass names remain unchanged, allowing smooth migration of except clauses.

4.1 Class Name Mapping

v1 v2 Description
AGNError AibridgeError Base class (renamed)
AuthenticationError AuthenticationError Authentication failure
RateLimitError RateLimitError Rate limiting
ValidationError ValidationError Parameter validation
ModelNotFoundError ModelNotFoundError Model not found
APIError APIError Provider API error
NetworkError NetworkError Network error
TimeoutError TimeoutError Timeout
UnsupportedCapabilityError UnsupportedCapabilityError Capability not supported
ProviderNotFoundError ProviderNotFoundError provider not found
VoiceNotAvailableError VoiceNotAvailableError Voice not available
ServiceUnavailableError ServiceUnavailableError Service temporarily unavailable

4.2 code Field Format Change

In v1 the code was an uppercase constant; in v2 it changes to snake_case (aligned with the Rust core):

# v1
except RateLimitError as e:
    assert e.code == "RATE_LIMIT_ERROR"

# v2
except RateLimitError as e:
    assert e.code == "rate_limit_error"  # snake_case

If your code hardcodes uppercase code strings, change them to snake_case when migrating. In v2 the exception message format is [code] message.

4.3 Migrating the Catch Syntax

# v1
from agn import AGNError, RateLimitError

try:
    resp = await client.chat(...)
except RateLimitError as e:
    print(f"限流,{e.retry_after} 秒后重试")
except AGNError as e:
    print(f"其他 SDK 错误: {e}")

# v2 (only the base class name changes)
from aibridge import AibridgeError, RateLimitError

try:
    resp = await client.chat(...)
except RateLimitError as e:
    print(f"限流,{e.retry_after} 秒后重试")
except AibridgeError as e:
    print(f"其他 SDK 错误: {e}")

5. Client Construction Mapping

v1

client = Client(
    provider="agnes",
    api_key="your-key",
    base_url="https://api.agnes.ai/v1",
    timeout=300,
    max_retries=3,
    retry_delay=2.0,
)
await client.start()

v2 (Python binding)

client = Client(
    provider="agnes",
    api_key="your-key",       # keyword argument
    base_url="https://api.agnes.ai/v1",
)
await client.start()

The v2 Python binding currently exposes two keyword arguments, api_key and base_url; timeout/max_retries/retry_delay go through environment variables or will be exposed in future releases. The Rust core's ClientOptions fully supports all connection parameters (see the Rust example below).

v2 (Rust core, full parameters)

use aibridge_core::client::Client;
use aibridge_core::config::ClientOptions;

let client = Client::new(
    "agnes",
    ClientOptions::builder()
        .api_key("your-key")
        .base_url("https://api.agnes.ai/v1")
        .timeout(300)
        .max_retries(3)
        .retry_delay(2.0)
        .build(),
)?;
client.start().await?;

Auth-free providers

edge-tts requires no authentication in both v1 and v2; do not pass api_key when constructing:

# v1
client = Client(provider="edge-tts")

# v2
client = Client(provider="edge-tts")

The additional echo in v2 is a mock adapter (auth-free, used for pipeline validation and unit tests).


6. Parameter-Passing Paradigm (Core Change)

This is the biggest change from v1 to v2: **kwargs + Options intermediate layer → explicit Request struct + Builder chained calls.

6.1 Paradigm Comparison

v1: three parameter-passing styles mixed

# Style A: standalone parameters
resp = await client.chat(model="gpt-4o", messages=[...], temperature=0.7, max_tokens=1000)

# Style B: Options intermediate layer (options take precedence over standalone parameters)
opts = ChatOptions(temperature=0.7, max_tokens=1000, top_p=0.9)
resp = await client.chat(model="gpt-4o", messages=[...], options=opts)

# Style C: **kwargs to pass through vendor-specific parameters
resp = await client.chat(model="gpt-4o", messages=[...], reasoning_effort="high")

v2: unified use of the Request builder (Rust core)

let req = ChatRequest::builder("gpt-4o", vec![ChatMessage::user("Hello!")])
    .temperature(0.7)
    .max_tokens(1000)
    .top_p(0.9)
    .extra("reasoning_effort", "high")  // vendor-specific parameters go through extra
    .build();
let resp = client.chat(req).await?;

v2: Python binding (exposed methods use keyword arguments)

# The Python binding remains keyword-argument style externally, but the Options intermediate layer is removed
resp = await client.chat(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}],
    temperature=0.7,
    max_tokens=1000,
)

6.2 All Options Classes Removed

v1 Options class v2 replacement
ChatOptions ChatRequest::builder(model, messages)
ImageOptions ImageRequest::builder(model, prompt)
VideoOptions VideoRequest::builder(model, prompt)
EmbedOptions EmbedRequest::builder(model, input)
TranscribeOptions TranscribeRequest::builder(model, file)
SpeechOptions SpeechRequest::builder(model, input, voice)

ParameterMapping and the preset mapping constants (OPENAI_COMPATIBLE_MAPPING, etc.) are internal implementation details of the Rust adapters in v2. Users no longer interact with them, so no migration is needed.

6.3 Passing Through Vendor-Specific Parameters

v1 uses **kwargs; v2 uses the extra field (HashMap<String, serde_json::Value>):

// v2 Rust: pass-through via extra
let req = ChatRequest::builder("gpt-4o", messages)
    .extra("reasoning_effort", "high")
    .extra("custom_flag", true)
    .build();

7. Capability-by-Capability Mapping (v1 vs v2 Examples)

The tables below give v1 and v2 code comparisons for the six major capabilities. On the v2 side, both the Rust core API (full capability) and the Python binding API (exposed methods) are shown. The echo adapter examples can run directly without authentication; real provider examples must be replaced with a valid API key.

7.1 Text Chat: chat

v1 (Python)

from agn import Client

client = Client(provider="agnes", api_key="your-key")
await client.start()

resp = await client.chat(
    model="claude-3-opus",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Hello!"},
    ],
    temperature=0.7,
    max_tokens=1000,
)
print(resp.choices[0].message.content)
await client.close()

v2 (Python binding, echo runs directly)

from aibridge import Client

client = Client(provider="echo")  # for a real use case change to "agnes" + api_key
await client.start()

resp = await client.chat(
    model="echo-chat",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Hello!"},
    ],
    temperature=0.7,
    max_tokens=1000,
)
print(resp.choices[0].message.content)
await client.close()

v2 (Rust core)

use aibridge_core::client::Client;
use aibridge_core::config::ClientOptions;
use aibridge_core::model::chat::{ChatMessage, ChatRequest};

let mut client = Client::new("agnes", ClientOptions::builder().api_key("your-key").build())?;
client.start().await?;

let req = ChatRequest::builder("claude-3-opus", vec![
    ChatMessage::system("You are a helpful assistant."),
    ChatMessage::user("Hello!"),
])
.temperature(0.7)
.max_tokens(1000)
.build();

let resp = client.chat(req).await?;
println!("{}", resp.choices[0].message.content.as_deref().unwrap_or(""));
client.close().await?;

7.2 Image Generation: image_generate

v1 (Python)

result = await client.image_generate(
    model="dall-e-3",
    prompt="A beautiful sunset over the ocean",
    size="1024x1024",
    n=1,
)
print(result.data[0].url)

v2 (Rust core; Python binding being exposed incrementally)

use aibridge_core::model::image::ImageRequest;

let req = ImageRequest::builder("dall-e-3", "A beautiful sunset over the ocean")
    .size("1024x1024")
    .n(1)
    .build();

let result = client.image_generate(req).await?;
println!("{}", result.data[0].url.as_deref().unwrap_or(""));

v2 uses ImageRequest::builder(model, prompt) for chained construction, replacing v1's standalone parameters + ImageOptions. In v2, reference_images is expressed uniformly with the FileInput enum (Path/Url/Bytes/Base64).

7.3 Video Generation: video_create + video_poll

v1 (Python)

task = await client.video_create(
    model="video-gen-1",
    prompt="A cat walking through a forest",
    width=1280,
    height=720,
)
print(task.task_id)

# Polling
status = await client.video_poll(task_id=task.task_id, model="video-gen-1")
print(status.status)

v2 (Rust core)

use aibridge_core::model::video::VideoRequest;

let req = VideoRequest::builder("video-gen-1", "A cat walking through a forest")
    .width(1280)
    .height(720)
    .build();

let task = client.video_create(req).await?;
println!("{}", task.task_id);

// Polling
let status = client.video_poll(&task.task_id, "video-gen-1").await?;
println!("{:?}", status.status);

video_poll has an identical signature in v1 and v2: (task_id, model). The VideoRequest's mode field uses the VideoMode enum (text2video/image2video/keyframes/multiimage), replacing v1's string literals.

7.4 Text-to-Speech: speech (TTS)

v1 (Python)

result = await client.speech(
    model="tts-1",
    input="你好,欢迎使用语音合成",
    voice="alloy",
    response_format="mp3",
    speed=1.0,
)
result.save_to_file("output.mp3")

v2 (Python binding, echo runs directly)

result = await client.speech(
    model="echo-tts",   # for a real use case change to "tts-1"
    input="hello",
    voice="alloy",
    response_format="mp3",
    speed=1.0,
)
with open("output.mp3", "wb") as f:
    f.write(result.audio_data)  # bytes

v2 (Rust core)

use aibridge_core::model::audio::SpeechRequest;

let req = SpeechRequest::builder("tts-1", "你好,欢迎使用语音合成", "alloy")
    .response_format("mp3")
    .speed(1.0)
    .build();

let result = client.speech(req).await?;
let audio: Vec<u8> = result.audio_data.unwrap_or_default();
std::fs::write("output.mp3", &audio)?;

The v2 SpeechResult.save_to_file() helper method is not yet exposed in the Python binding layer; you can write result.audio_data (bytes) to a file directly. In the v2 Rust core, voice uses VoiceSpec (supporting a candidate list with automatic fallback); the Python binding accepts a string.

7.5 Speech-to-Text: transcribe (ASR)

v1 (Python)

result = await client.transcribe(
    model="whisper-1",
    file="/path/to/audio.mp3",
    language="zh",
    prompt="这是一段关于人工智能的对话",
)
print(result.text)

v2 (Rust core; Python binding being exposed incrementally)

use aibridge_core::model::audio::TranscribeRequest;
use aibridge_core::model::image::FileInput;

let req = TranscribeRequest::builder("whisper-1", FileInput::path("/path/to/audio.mp3"))
    .language("zh")
    .prompt("这是一段关于人工智能的对话")
    .build();

let result = client.transcribe(req).await?;
println!("{}", result.text);

v2 uses the FileInput enum to express audio input uniformly (Path/Url/Bytes/Base64), replacing v1's file parameter that accepted multiple types.

Translation (translate) change: v1's client.translate(...) is merged into transcribe in v2, using the translate(true) switch:

// v2 translate to English
let req = TranscribeRequest::builder("whisper-1", FileInput::path("/path/to/chinese.mp3"))
    .translate(true)  // enable translation mode
    .build();
let result = client.transcribe(req).await?;  // result.task == "translate"

7.6 Text Embedding: embed

v1 (Python)

result = await client.embed(
    model="text-embedding-3-small",
    input="hello world",
)
print(result.get_embeddings()[0][:5])

v2 (Rust core; Python binding being exposed incrementally)

use aibridge_core::model::common::EmbedRequest;

let req = EmbedRequest::builder("text-embedding-3-small", "hello world").build();
let result = client.embed(req).await?;
// result.data[0].embedding is the vector

8. Streaming Chat Mapping

v1: chat(stream=True) — one method, two return types

# v1: stream=False returns ChatCompletion, stream=True returns AsyncGenerator
resp = await client.chat(model="gpt-4o", messages=[...], stream=True)
async for chunk in resp:
    print(chunk.choices[0].delta.content, end="", flush=True)

v2: the separate chat_stream method

v2 splits streaming into a separate method chat_stream, which returns an async iterator. The semantics are identical to v1 (yielding ChatCompletionChunk chunk by chunk).

v2 (Python binding, echo runs directly)

stream = await client.chat_stream(
    model="echo-chat",
    messages=[{"role": "user", "content": "hello"}],
)
async for chunk in stream:
    # chunk.choices[0].delta.content is the incremental text
    print(chunk.choices[0].content, end="", flush=True)

v2 (Rust core)

let req = ChatRequest::builder("gpt-4o", vec![ChatMessage::user("Hello!")])
    .stream(true)
    .build();

use futures::StreamExt;
let mut stream = client.chat_stream(req).await?;
while let Some(chunk_result) = stream.next().await {
    let chunk = chunk_result?;
    if let Some(delta) = chunk.choices.first() {
        if let Some(content) = &delta.delta.content {
            print!("{}", content);
        }
    }
}

Cancellation mechanism: in Python, simply cancel the coroutine with asyncio (on the Rust side, the stream is automatically dropped → tokio task abort).


9. Provider List Mapping

v2 fully migrates all 38 providers from v1, preserving names and aliases completely — zero migration cost. The table below lists them by category.

9.1 Complete Provider List

Category provider (main name) Aliases
MVP openai agnes volcengine_cv gemini
Compatible family azure
Aggregation platforms siliconflow togetherai fireworksai cloudflareai sf / together / fireworks / cloudflare, workersai
Extended models grok yi sensenova hunyuan groq xaigrok / lingyiwanwu / shangtang / tencent_hunyuan
More models deepseek stepfun mistral cohere perplexity step
Emerging models ideogram luma llama ideo / dream-machine, lumalabs / meta-llama, meta
Chinese models qwen zhipu doubao ernie kimi minimax
Standalone protocols anthropic stability runway pika kling
Audio TTS edge-tts elevenlabs cartesia edge_tts, edge / eleven, 11labs / sonic
Audio ASR deepgram assemblyai dg / assembly, aai
Mock echo

9.2 v1 → v2 Provider Compatibility

  • All 38 providers preserved: every provider name used in v1 is available in v2, with no renaming needed.
  • Aliases preserved: v1's aliases (e.g., sfsiliconflow) are exactly the same in v2.
  • Auth-free providers: edge-tts requires no authentication in both v1 and v2; v2 adds the echo mock adapter (auth-free, for testing).
  • The "free providers require no authentication" feature since v1.3.0 is preserved.
  • The "real-time model list fetching" (list_models calls the provider's /models endpoint) since v1.1.0 is preserved.
  • The "TTS voice health check / recommendation / automatic fallback" since v1.3.3 is preserved.

9.3 New Providers

Relative to v1, v2 adds the echo mock adapter during the design phase (used for pipeline validation in phase 0.6, always available, makes no network calls). Real providers are on par with v1.3.3.


10. Environment Variable Mapping

v2 introduces a new prefix AIBRIDGE_, while remaining compatible with the legacy AGN_ prefix (they coexist during the migration period for a smooth transition).

Purpose v1 v2 (new) v2 (legacy-compatible)
Global API Key AGN_API_KEY AIBRIDGE_API_KEY AGN_API_KEY
Provider-specific Key AGN_OPENAI_API_KEY AIBRIDGE_OPENAI_API_KEY AGN_OPENAI_API_KEY
Global Base URL AGN_BASE_URL AIBRIDGE_BASE_URL AGN_BASE_URL
Provider-specific URL AGN_OPENAI_BASE_URL AIBRIDGE_OPENAI_BASE_URL AGN_OPENAI_BASE_URL
Poll URL (video) AGN_{PROVIDER}_POLL_URL AIBRIDGE_{PROVIDER}_POLL_URL AGN_{PROVIDER}_POLL_URL

Priority: explicit values passed in code > AIBRIDGE_{PROVIDER}_* > AGN_{PROVIDER}_* > AIBRIDGE_API_KEY > AGN_API_KEY.

During the migration period you can keep using the legacy AGN_* environment variables, with no immediate change required. New projects are recommended to use the AIBRIDGE_* prefix.


11. Breaking Changes Checklist

The following are the items where v1 usage must be modified for v2 — verify each one:

# v1 usage v2 requirement Must change
1 from agn import ... from aibridge import ... Yes
2 pip install agn-sdk pip install aibridge Yes
3 except AGNError except AibridgeError Yes
4 e.code == "RATE_LIMIT_ERROR" e.code == "rate_limit_error" Yes (if parsing code)
5 chat(stream=True) chat_stream(...) as a separate method Yes
6 client.translate(...) transcribe(req, translate=true) Yes
7 ChatOptions(...) + options= Removed, pass parameters directly Yes
8 ImageOptions/VideoOptions/... Removed, use builder Yes
9 **kwargs pass-through of vendor parameters extra("key", value) Yes (Rust) / keyword arguments (Python)
10 result.save_to_file() Manually write audio_data to a file Yes (TTS; the Python binding does not yet expose the helper method)
11 Client(provider, api_key, base_url, timeout, ...) with all positional/keyword arguments Client(provider, *, api_key, base_url) (Python binding) Yes (timeout, etc. go through environment variables)
12 from agn import ChatOptions, ImageOptions, ... Removed (v2 has no Options classes) Yes

Unchanged items (confirmed no change needed): - Method names: chat/image_generate/video_create/video_poll/embed/transcribe/speech/list_models/list_voices/recommend_voices all unchanged - provider names and aliases: all unchanged - Error subclass names: all unchanged - Async context manager: async with client: semantics unchanged - Response model field names: ChatCompletion.choices[0].message.content, etc. are largely aligned


12. Migration Checklist

Check each item in order to ensure a complete migration:

  • [ ] Dependency: pip uninstall agn-sdk && pip install aibridge
  • [ ] Global replace imports: from agnfrom aibridge
  • [ ] Error base class: AGNErrorAibridgeError (subclass names untouched)
  • [ ] Error code strings: uppercase → snake_case (if hardcoded)
  • [ ] Remove all ChatOptions/ImageOptions/VideoOptions/EmbedOptions/TranscribeOptions/SpeechOptions usage
  • [ ] Streaming calls: chat(stream=True)chat_stream(...)
  • [ ] Translation calls: translate(...)transcribe(req, translate=true)
  • [ ] TTS file saving: result.save_to_file(path) → manually write result.audio_data
  • [ ] Client construction: move timeout/max_retries/retry_delay to environment variables (or wait for a future release to expose them)
  • [ ] Environment variables: you can keep using AGN_*; AIBRIDGE_* is recommended for new code
  • [ ] provider names and aliases: no change needed (fully preserved)
  • [ ] Run tests: use the echo adapter for an auth-free smoke test (Client(provider="echo"))

13. Migration Example: Full Script Comparison

Below is a full-script v1→v2 migration comparison, covering chat + streaming + speech.

v1 Full Script

import asyncio
from agn import Client, ChatOptions, AGNError, RateLimitError

async def main():
    client = Client(provider="agnes", api_key="your-key", base_url="https://api.agnes.ai/v1")
    async with client:
        # Chat
        opts = ChatOptions(temperature=0.7, max_tokens=1000)
        resp = await client.chat(
            model="claude-3-opus",
            messages=[{"role": "user", "content": "Hello!"}],
            options=opts,
        )
        print(resp.choices[0].message.content)

        # Streaming
        stream = await client.chat(
            model="claude-3-opus",
            messages=[{"role": "user", "content": "讲个笑话"}],
            stream=True,
        )
        async for chunk in stream:
            print(chunk.choices[0].delta.content or "", end="", flush=True)
        print()

        # TTS
        audio = await client.speech(model="tts-1", input="你好", voice="alloy")
        audio.save_to_file("hello.mp3")

asyncio.run(main())

v2 Full Script (Python binding)

import asyncio
from aibridge import Client, AibridgeError, RateLimitError

async def main():
    client = Client(provider="agnes", api_key="your-key", base_url="https://api.agnes.ai/v1")
    async with client:
        # Chat (drop Options, pass keyword arguments directly)
        resp = await client.chat(
            model="claude-3-opus",
            messages=[{"role": "user", "content": "Hello!"}],
            temperature=0.7,
            max_tokens=1000,
        )
        print(resp.choices[0].message.content)

        # Streaming (separate method chat_stream)
        stream = await client.chat_stream(
            model="claude-3-opus",
            messages=[{"role": "user", "content": "讲个笑话"}],
        )
        async for chunk in stream:
            print(chunk.choices[0].content or "", end="", flush=True)
        print()

        # TTS (manually write file)
        audio = await client.speech(model="tts-1", input="你好", voice="alloy")
        with open("hello.mp3", "wb") as f:
            f.write(audio.audio_data)

asyncio.run(main())

14. FAQ

Q1: Why are some capabilities not yet exposed in the v2 Python binding? A: v2 is a Rust core + five-language bindings architecture. The Rust core already fully implements 38 providers + six major capabilities; the Python binding (PyO3) currently exposes chat/chat_stream/speech, with the remaining capabilities (image_generate/video_*/embed/transcribe/list_models/list_voices) exposed across future releases. If you urgently need full capabilities, you can use the Rust core directly or wait for the binding layer to catch up.

Q2: Will performance improve after migration? A: Yes. The Rust core has no GIL, native async, and zero-cost abstractions; in IO-intensive scenarios its throughput and latency are significantly better than Python. The Python binding connects directly to the Rust core via PyO3 (no JSON serialization boundary), and real IO executes on tokio worker threads without blocking the asyncio event loop.

Q3: Can v1 and v2 coexist? A: Yes. They have different package names (agn-sdk vs aibridge) and different import paths (agn vs aibridge), so they can coexist in the same environment. However, it is recommended to uninstall v1 after migration to avoid confusion.

Q4: Must environment variables be changed? A: No. v2 is compatible with the legacy AGN_* prefix, so you can keep using it during migration. AIBRIDGE_* is recommended for new projects.

Q5: Will the old v1 be archived? A: Yes. After v2 is officially released, the v1 repository will be archived and preserved, and agn-sdk on PyPI will no longer be updated. Migrating to aibridge is recommended.


  • Design: architecture, data models, FFI boundary, error handling
  • Progress: current implementation progress and handover guide
  • README (v2): five-language quick start + provider list
  • Original README (v1): Python v1 documentation (archived reference)