elph-ai

Unified LLM API with provider collections, automatic auth resolution, token and cost tracking, and simple context persistence and hand-off to other models mid-session. Rust port of @earendil-works/pi-ai.

Note: This library only includes models that support tool calling (function calling), as this is essential for agentic workflows.

Table of Contents

• Supported Providers
• Installation
• Quick Start
• Providers and Models
  • Provider Factories
  • All Built-in Providers
  • Querying Models
  • Static Catalog Reads
  • Dynamic Providers
• Auth
  • How Auth Resolves
  • Credential Store
  • Environment Variables
• Tools
  • Defining Tools
  • Handling Tool Calls
  • Streaming Tool Calls with Partial JSON
  • Validating Tool Arguments
  • Complete Event Reference
• Image Input
• Image Generation
• Thinking/Reasoning
• Stream Options
• Request Cancellation
• Stop Reasons
• Error Handling
• HTTP and WebSocket Proxies
• Custom Providers
• Faux Provider for Tests
• Cross-Provider Handoffs
• Context Serialization
• OAuth Providers
• Development
• License

Supported Providers

• OpenAI
• Ant Ling
• Azure OpenAI (Responses)
• OpenAI Codex (ChatGPT Plus/Pro subscription, requires OAuth)
• DeepSeek
• NVIDIA NIM
• Anthropic
• Google
• Vertex AI (Gemini via Vertex AI)
• Mistral
• Groq
• Cerebras
• Cloudflare AI Gateway
• Cloudflare Workers AI
• xAI
• OpenRouter
• Vercel AI Gateway
• ZAI Coding Plan (Global) (with separate China provider)
• MiniMax (with separate China provider)
• Together AI
• Hugging Face
• Moonshot AI (with separate China provider)
• GitHub Copilot (requires OAuth)
• Amazon Bedrock
• OpenCode Zen
• OpenCode Go
• Fireworks (OpenAI- and Anthropic-compatible APIs)
• Kimi For Coding (Moonshot AI subscription endpoint, Anthropic-compatible API)
• Xiaomi MiMo (API billing endpoint, with separate Token Plan providers for cn/ams/sgp)
• Any OpenAI-compatible API: Ollama, vLLM, LM Studio, etc. (via custom providers)

Image generation is currently available through OpenRouter (openrouter-images API).

Installation

Add to your Cargo.toml:

[dependencies]
elph-ai = "0.0.21"
tokio = { version = "1", features = ["macros", "rt-multi-thread"] }

Or from the workspace:

cargo add elph-ai

Quick Start

Build a Models collection of providers and stream through it. The quickest start registers every built-in provider; apps that only need a subset can register individual provider factories instead (see Provider Factories).

use elph_ai::{AssistantContentBlock, AssistantMessageEvent, Context, Message};
use elph_ai::{SimpleStreamOptions, Tool, UserContent, ThinkingLevel};
use elph_ai::{builtin_models, get_builtin_model};
use serde_json::json;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let models = builtin_models(None);
    let model = get_builtin_model("openai", "gpt-4o-mini")
        .ok_or_else(|| anyhow::anyhow!("model not found"))?;

    let tools = vec![Tool {
        name: "get_time".into(),
        description: "Get the current time".into(),
        parameters: json!({
            "type": "object",
            "properties": {
                "timezone": {
                    "type": "string",
                    "description": "Optional timezone (e.g., Asia/Jakarta)"
                }
            }
        }),
    }];

    let context = Context {
        system_prompt: Some("You are a helpful assistant.".into()),
        messages: vec![Message::User {
            content: UserContent::Text("What time is it?".into()),
            timestamp: chrono::Utc::now().timestamp_millis(),
        }],
        tools: Some(tools),
    };

    // Option 1: Streaming with all event types.
    // Auth resolves through the provider (OPENAI_API_KEY from the environment here).
    let stream = models.stream(&model, &context, None);
    let mut events = stream.into_stream();

    while let Some(event) = events.next().await {
        match event {
            AssistantMessageEvent::TextDelta { delta, .. } => print!("{delta}"),
            AssistantMessageEvent::ToolcallEnd { tool_call, .. } => {
                println!("\nTool called: {}({})", tool_call.name, tool_call.arguments);
            }
            AssistantMessageEvent::Done { reason, message } => {
                println!("\nFinished: {reason:?}");
                println!(
                    "Tokens: {} in, {} out, cost ${:.4}",
                    message.usage.input,
                    message.usage.output,
                    message.usage.cost.total
                );
            }
            AssistantMessageEvent::Error { error, .. } => {
                eprintln!("Error: {}", error.error_message.unwrap_or_default());
            }
            _ => {}
        }
    }

    // Option 2: Buffered completion without manually iterating events
    let response = models.complete(&model, &context, None).await;
    for block in &response.content {
        if let AssistantContentBlock::Text(text) = block {
            println!("{}", text.text);
        }
    }

    // Option 3: Simplified reasoning interface
    let _ = models
        .complete_simple(
            &model,
            &context,
            Some(SimpleStreamOptions {
                reasoning: Some(ThinkingLevel::Medium),
                ..Default::default()
            }),
        )
        .await;

    Ok(())
}

See examples/opencode_big_pickle.rs for a runnable example with progress output and streaming flags.

Providers and Models

A provider is the runtime unit: it owns its model catalog, its auth (API key resolution, OAuth flows), and its stream behavior. A Models collection holds providers and routes every request to the provider that owns the model.

Providers internally share API implementations (the wire protocols): Anthropic models use anthropic-messages, OpenAI uses openai-responses, while xAI, Groq, Cerebras, OpenRouter, and most others share openai-completions. Mixed-API providers (GitHub Copilot, OpenCode Zen, Fireworks) dispatch per model.

Nine chat APIs are registered in elph_ai::api::builtin_apis():

API ID	Typical providers
anthropic-messages	Anthropic, Kimi For Coding, parts of Fireworks / GitHub Copilot
openai-completions	Groq, Cerebras, OpenRouter, DeepSeek, Ollama-compatible endpoints, etc.
openai-responses	OpenAI
openai-codex-responses	OpenAI Codex (ChatGPT subscription)
azure-openai-responses	Azure OpenAI
google-generative-ai	Google Gemini
google-vertex	Vertex AI
mistral-conversations	Mistral
bedrock-converse-stream	Amazon Bedrock

Image generation uses a separate openrouter-images API (see Image Generation). Use api_for("anthropic-messages") or call modules under elph_ai::api for lower-level control.

Model catalogs are embedded as JSON under models/ and loaded at compile time via include_str!.

Provider Factories

For apps that only need specific providers, register individual factories from elph_ai::providers:

use elph_ai::{create_models, MutableModels};
use elph_ai::providers::{anthropic_provider, openai_provider};

let mut models = create_models(None);
models.set_provider(anthropic_provider());
models.set_provider(openai_provider());

Additional factories live in elph_ai::providers::builtin (amazon_bedrock_provider, google_vertex_provider, github_copilot_provider, etc.). Use builtin_providers() to inspect the full list.

All Built-in Providers

use elph_ai::builtin_models;

let models = builtin_models(None); // every built-in provider registered

builtin_models() accepts the same options as create_models() (credentials, auth_context). builtin_providers() returns the provider list if you want to register them on your own collection.

Querying Models

Reads are synchronous and return the last-known lists:

let providers = models.get_providers();
let provider = models.get_provider("anthropic");

let all = models.get_models(None);
let anthropic_models = models.get_models(Some("anthropic"));
let model = models.get_model("anthropic", "claude-sonnet-4-5");

for m in anthropic_models {
    println!("{}: {}", m.id, m.name);
    println!("  API: {}", m.api);
    println!("  Context: {} tokens", m.context_window);
    println!("  Vision: {}", m.input.iter().any(|i| i == "image"));
    println!("  Reasoning: {}", m.reasoning);
}

Narrow dynamically looked-up models with has_api() when you need API-specific option typing:

use elph_ai::has_api;

if let Some(m) = models.get_model("anthropic", "claude-sonnet-4-5") {
    if has_api(&m, "anthropic-messages") {
        // stream options for anthropic-messages are available on StreamOptions
        let _ = models.stream(&m, &context, None);
    }
}

Static Catalog Reads

For tooling that wants the embedded built-in catalog independent of any collection:

use elph_ai::{get_builtin_model, get_builtin_models, get_builtin_providers};

let model = get_builtin_model("openai", "gpt-4o-mini");
let providers = get_builtin_providers();
let anthropic = get_builtin_models("anthropic");

Image model catalogs are separate:

use elph_ai::images::get_builtin_image_models;

let openrouter_images = get_builtin_image_models("openrouter");

Dynamic Providers

Providers may have dynamic model lists (a llama.cpp server, a live OpenRouter listing). Reads stay sync; fetching is an explicit async verb:

// get_models() returns the last-known list (empty before the first refresh)
models.refresh(Some("llamacpp")).await?; // one provider; rejects on failure
models.refresh(None).await?;            // all providers concurrently, best-effort
let fresh = models.get_model("llamacpp", "qwen3-30b");

Static built-in providers are no-ops for refresh(). See Custom Providers for building a dynamic provider.

Auth

Every provider owns its auth: how API keys resolve (stored credentials, environment variables, ambient sources like AWS profiles or gcloud ADC) and, where supported, OAuth login/refresh flows.

How Auth Resolves

When you call models.stream(), the collection resolves auth through the owning provider and merges it into the request. Explicit per-request values always win:

// Resolved through the provider (env var, stored credential, OAuth token):
models.complete(&model, &context, None).await;

// Explicit key wins over anything the provider would resolve:
models.complete(
    &model,
    &context,
    Some(StreamOptions {
        api_key: Some("sk-explicit".into()),
        ..Default::default()
    }),
)
.await;

Inspect resolution without making a request — useful for status UIs:

let auth = models.get_auth(&model).await?;
if let Some(auth) = &auth {
    println!("configured via {}", auth.source.as_deref().unwrap_or("unknown"));
} else {
    println!("not configured");
}

get_auth() returns Ok(None) for unconfigured providers and Err(ModelsError) when something is broken (ModelsErrorCode::Oauth: token refresh failed; ModelsErrorCode::Auth: key resolution or credential store failure). Request paths surface the same failures as stream errors.

Credential Store

Stored credentials (API keys entered interactively, OAuth tokens) live in a CredentialStore — one type-tagged credential per provider. elph-ai ships an in-memory default; apps inject persistent storage:

use elph_ai::{CreateModelsOptions, create_models, InMemoryCredentialStore};
use std::sync::Arc;

let models = create_models(Some(CreateModelsOptions {
    credentials: Some(Arc::new(my_file_backed_store)),
    auth_context: None,
}));

The contract is small: read(provider_id), modify(provider_id, fn) (serialized read-modify-write), and delete(provider_id). OAuth token refresh runs inside modify, so concurrent requests cannot double-refresh a rotated token. A stored credential owns its provider: environment variables are only consulted when nothing is stored.

API-key credentials can carry provider-scoped env/config values:

{
    "type": "api_key",
    "key": "...",
    "env": {
        "CLOUDFLARE_ACCOUNT_ID": "account-id",
        "CLOUDFLARE_GATEWAY_ID": "gateway-id"
    }
}

Environment Variables

Built-in providers resolve these environment variables:

Provider	Environment Variable(s)
OpenAI	OPENAI_API_KEY
Ant Ling	ANT_LING_API_KEY
Azure OpenAI	AZURE_OPENAI_API_KEY + AZURE_OPENAI_BASE_URL or AZURE_OPENAI_RESOURCE_NAME. Optional: AZURE_OPENAI_API_VERSION, AZURE_OPENAI_DEPLOYMENT_NAME_MAP
Anthropic	ANTHROPIC_API_KEY or ANTHROPIC_OAUTH_TOKEN
DeepSeek	DEEPSEEK_API_KEY
NVIDIA NIM	NVIDIA_API_KEY
Google	GEMINI_API_KEY
Vertex AI	GOOGLE_CLOUD_API_KEY or GOOGLE_CLOUD_PROJECT (or GCLOUD_PROJECT) + GOOGLE_CLOUD_LOCATION + ADC
Mistral	MISTRAL_API_KEY
Groq	GROQ_API_KEY
Cerebras	CEREBRAS_API_KEY
Cloudflare AI Gateway	CLOUDFLARE_API_KEY + CLOUDFLARE_ACCOUNT_ID + CLOUDFLARE_GATEWAY_ID
Cloudflare Workers AI	CLOUDFLARE_API_KEY + CLOUDFLARE_ACCOUNT_ID
xAI	XAI_API_KEY
Fireworks	FIREWORKS_API_KEY
Together AI	TOGETHER_API_KEY
OpenRouter	OPENROUTER_API_KEY
Vercel AI Gateway	VERCEL_AI_GATEWAY_API_KEY
ZAI Coding Plan (Global)	ZAI_API_KEY
ZAI Coding Plan (China)	ZAI_CODING_CN_API_KEY
MiniMax (Global)	MINIMAX_API_KEY
MiniMax (China)	MINIMAX_CN_API_KEY
Moonshot AI / Moonshot AI (China)	MOONSHOT_API_KEY
Hugging Face	HF_TOKEN
OpenCode Zen / OpenCode Go	OPENCODE_API_KEY
Kimi For Coding	KIMI_API_KEY
Xiaomi MiMo (API billing)	XIAOMI_API_KEY
Xiaomi MiMo Token Plan (China/AMS/SGP)	XIAOMI_API_KEY
GitHub Copilot	COPILOT_GITHUB_TOKEN
Amazon Bedrock	AWS_REGION or AWS_DEFAULT_REGION, AWS_PROFILE, AWS_BEARER_TOKEN_BEDROCK (bearer auth path). Optional: AWS_BEDROCK_FORCE_CACHE=1, ELPH_CACHE_RETENTION=long

Amazon Bedrock also resolves ambient AWS credentials (access key pairs, ECS task roles, web identity tokens) when no bearer token is set. Vertex AI resolves either an explicit key or gcloud Application Default Credentials plus project/location.

Per-request StreamOptions.env and stored credential env maps override process environment for the same keys. Global tuning variables:

Variable	Effect
ELPH_CACHE_RETENTION=long	Default prompt cache retention to long when cache_retention is unset (Anthropic, OpenAI Responses, Bedrock Claude models)
HTTP_PROXY / HTTPS_PROXY / ALL_PROXY	HTTP(S) proxy for outbound provider requests (see HTTP and WebSocket Proxies)
NO_PROXY	Hostnames/ports to bypass the proxy (*, comma-separated, optional :port suffix)

Tools

Tools enable LLMs to interact with external systems. Tool parameters are JSON Schema values (serde_json::Value), validated with the jsonschema crate.

Defining Tools

use elph_ai::Tool;
use serde_json::json;

let weather_tool = Tool {
    name: "get_weather".into(),
    description: "Get current weather for a location".into(),
    parameters: json!({
        "type": "object",
        "properties": {
            "location": { "type": "string", "description": "City name or coordinates" },
            "units": { "type": "string", "enum": ["celsius", "fahrenheit"], "default": "celsius" }
        },
        "required": ["location"]
    }),
};

For Google API compatibility, prefer enum arrays over complex anyOf/const patterns in schemas.

Handling Tool Calls

Tool results use content blocks and can include both text and images:

use elph_ai::{ContentBlock, Message};

let response = models.complete(&model, &context, None).await;

for block in &response.content {
    if let AssistantContentBlock::ToolCall(call) = block {
        context.messages.push(Message::ToolResult {
            tool_call_id: call.id.clone(),
            tool_name: call.name.clone(),
            content: vec![ContentBlock::Text {
                text: r#"{"temp": 18}"#.into(),
            }],
            details: None,
            is_error: false,
            timestamp: chrono::Utc::now().timestamp_millis(),
        });
    }
}

// Tool results can also include images (for vision-capable models)
context.messages.push(Message::ToolResult {
    tool_call_id: "tool_xyz".into(),
    tool_name: "generate_chart".into(),
    content: vec![
        ContentBlock::Text {
            text: "Generated chart showing temperature trends".into(),
        },
        ContentBlock::Image {
            data: base64_chart,
            mime_type: "image/png".into(),
        },
    ],
    details: None,
    is_error: false,
    timestamp: chrono::Utc::now().timestamp_millis(),
});

Streaming Tool Calls with Partial JSON

During streaming, tool call arguments are progressively parsed as they arrive:

let stream = models.stream(&model, &context, None);
let mut events = stream.into_stream();

while let Some(event) = events.next().await {
    match event {
        AssistantMessageEvent::ToolcallDelta { partial, content_index, .. } => {
            if let Some(AssistantContentBlock::ToolCall(call)) = partial.content.get(content_index) {
                // BE DEFENSIVE: arguments may be incomplete during streaming
                if call.name == "write_file" {
                    if let Some(path) = call.arguments.get("path").and_then(|v| v.as_str()) {
                        println!("Writing to: {path}");
                    }
                }
            }
        }
        AssistantMessageEvent::ToolcallEnd { tool_call, .. } => {
            println!("Tool completed: {} {:?}", tool_call.name, tool_call.arguments);
        }
        _ => {}
    }
}

Important notes about partial tool arguments:

• During ToolcallDelta events, arguments contains the best-effort parse of partial JSON
• Fields may be missing or incomplete — always check for existence before use
• At minimum, arguments will be an empty object, never missing
• The Google provider does not support function call streaming; you receive a single ToolcallDelta with full arguments

Validating Tool Arguments

Use validate_tool_call before executing tools:

use elph_ai::validation::validate_tool_call;

if let AssistantMessageEvent::ToolcallEnd { tool_call, .. } = event {
    let tool = tools.iter().find(|t| t.name == tool_call.name).unwrap();
    match validate_tool_call(tool, &tool_call) {
        Ok(()) => { /* execute tool */ }
        Err(msg) => {
            context.messages.push(Message::ToolResult {
                tool_call_id: tool_call.id.clone(),
                tool_name: tool_call.name.clone(),
                content: vec![ContentBlock::Text { text: msg }],
                details: None,
                is_error: true,
                timestamp: chrono::Utc::now().timestamp_millis(),
            });
        }
    }
}

Complete Event Reference

Event	Description	Key fields
Start	Stream begins	partial
TextStart	Text block starts	content_index
TextDelta	Text chunk received	delta, content_index
TextEnd	Text block complete	content, content_index
ThinkingStart	Thinking block starts	content_index
ThinkingDelta	Thinking chunk received	delta, content_index
ThinkingEnd	Thinking block complete	content, content_index
ToolcallStart	Tool call begins	content_index
ToolcallDelta	Tool arguments streaming	delta, partial.content[content_index].arguments
ToolcallEnd	Tool call complete	tool_call
Done	Stream complete	reason, message
Error	Stream failed	reason, error

Events serialize as snake_case JSON (text_delta, toolcall_end, etc.) via serde.

Image Input

User messages support text and image content blocks for vision-capable models:

let context = Context {
    messages: vec![Message::User {
        content: UserContent::Blocks(vec![
            ContentBlock::Text { text: "What's in this image?".into() },
            ContentBlock::Image {
                data: base64_png,
                mime_type: "image/png".into(),
            },
        ]),
        timestamp: chrono::Utc::now().timestamp_millis(),
    }],
    system_prompt: None,
    tools: None,
};

Image Generation

Image generation uses a separate API surface from text/chat generation: an ImagesModels collection holds ImagesProviders, reads are sync, and auth resolves through the owning provider. Image generation is one-shot — use generate_images(), not the chat/stream APIs.

use elph_ai::{builtin_images_models, ContentBlock, ImagesContext};
use elph_ai::images::get_builtin_image_models;

let images = builtin_images_models(None);
let model = get_builtin_image_models("openrouter")
    .into_iter()
    .find(|m| m.id.contains("gemini"))
    .unwrap();

let result = images
    .generate_images(
        &model,
        &ImagesContext {
            input: vec![ContentBlock::Text {
                text: "Generate a red circle on a plain white background.".into(),
            }],
        },
        None,
    )
    .await;

for block in &result.output {
    match block {
        ContentBlock::Text { text } => println!("{text}"),
        ContentBlock::Image { mime_type, .. } => println!("image: {mime_type}"),
    }
}

Check capabilities on model metadata:

println!("input: {:?}", model.input);   // ["text", "image"]
println!("output: {:?}", model.output); // ["image"] or ["image", "text"]

Failures return an AssistantImages with stop_reason: Error rather than panicking.

ImagesOptions mirrors chat StreamOptions for auth, timeouts, retries, proxy env, payload/response hooks, and cancellation:

use elph_ai::ImagesOptions;
use tokio_util::sync::CancellationToken;

let token = CancellationToken::new();
// cancel token when the user dismisses the UI
images.generate_images(
    &model,
    &context,
    Some(ImagesOptions {
        signal: Some(token),
        api_key: None,
        env: None,
        headers: None,
        timeout_ms: None,
        max_retries: None,
        on_payload: None,
        on_response: None,
    }),
)
.await;

Thinking/Reasoning

Many models support thinking/reasoning. Check model.reasoning; options passed to non-reasoning models are silently ignored.

Unified Interface (stream_simple / complete_simple)

use elph_ai::{SimpleStreamOptions, ThinkingLevel};

let response = models
    .complete_simple(
        &model,
        &context,
        Some(SimpleStreamOptions {
            reasoning: Some(ThinkingLevel::Medium),
            ..Default::default()
        }),
    )
    .await;

for block in &response.content {
    match block {
        AssistantContentBlock::Thinking(t) => println!("Thinking: {}", t.thinking),
        AssistantContentBlock::Text(t) => println!("Response: {}", t.text),
        _ => {}
    }
}

Use get_supported_thinking_levels() and clamp_thinking_level() to respect per-model capability maps.

Provider-Specific Options (stream / complete)

stream() / complete() accept the owning API's full StreamOptions. Use has_api() to narrow models before passing API-specific fields (thinking_enabled, reasoning_effort, etc.).

Streaming Thinking Content

while let Some(event) = events.next().await {
    match event {
        AssistantMessageEvent::ThinkingDelta { delta, .. } => print!("{delta}"),
        AssistantMessageEvent::ThinkingEnd { .. } => println!("\n[Thinking complete]"),
        _ => {}
    }
}

Stream Options

stream() / complete() accept StreamOptions; stream_simple() / complete_simple() wrap the same fields in SimpleStreamOptions.base plus reasoning knobs.

Field	Purpose
temperature, max_tokens	Sampling controls (max_tokens is clamped to remaining context)
api_key	Explicit key; overrides provider auth resolution
transport	Transport hint (sse, websocket, websocket-cached, auto) — used by OpenAI Codex when calling the API directly
cache_retention	Prompt cache retention (none, short, long); defaults from ELPH_CACHE_RETENTION
session_id	Stable session id (Codex WebSocket context reuse, request tracing headers)
headers	Per-request header overrides (None removes a model default header)
timeout_ms, websocket_connect_timeout_ms	HTTP and Codex WebSocket connect timeouts
max_retries, max_retry_delay_ms	Retry policy for transient failures
metadata	Opaque JSON attached to provider payloads where supported
env	Scoped environment map (proxy vars, Bedrock region, provider config)
on_payload	Async hook to inspect or rewrite the outgoing JSON body
on_response	Async hook invoked with HTTP status/headers after the provider responds
signal	CancellationToken for cooperative abort (see Request Cancellation)

Provider-specific option structs (AnthropicOptions, OpenAICompletionsOptions, BedrockOptions, etc.) extend base: StreamOptions when you call elph_ai::api modules directly.

Chat streams parse provider SSE incrementally — events are emitted as chunks arrive rather than buffering the full response body first.

Request Cancellation

Pass a tokio_util::sync::CancellationToken in StreamOptions.signal (or SimpleStreamOptions.base.signal / ImagesOptions.signal). When cancelled:

• In-flight HTTP requests and SSE parsers stop promptly
• The final AssistantMessage / AssistantImages uses stop_reason: Aborted
• Mid-stream partial content may be preserved on the final message when cancellation happens during generation

use tokio_util::sync::CancellationToken;

let token = CancellationToken::new();
let stream = models.stream(
    &model,
    &context,
    Some(StreamOptions {
        signal: Some(token.clone()),
        ..Default::default()
    }),
);

// elsewhere: token.cancel();
let message = stream.result().await;
assert_eq!(message.stop_reason, StopReason::Aborted);

Cancellation is checked before the request is sent, while waiting on the network, and between SSE/WebSocket events. See tests/abort.rs and tests/sse_abort.rs.

Stop Reasons

Reason	Meaning
Stop	Natural completion
Length	Hit max_tokens
ToolUse	Model wants to call tools
Error	Request failed
Aborted	Request was cancelled

Error Handling

Request failures do not panic out of stream functions. Errors arrive as AssistantMessageEvent::Error and the final message carries details:

while let Some(event) = events.next().await {
    if let AssistantMessageEvent::Error { error, reason } = event {
        eprintln!("Error ({reason:?}): {}", error.error_message.unwrap_or_default());
    }
}

let message = stream.result().await;
if matches!(message.stop_reason, StopReason::Error | StopReason::Aborted) {
    eprintln!("Request failed: {}", message.error_message.unwrap_or_default());
    // message.content may contain partial content received before the error
}

Debugging Provider Payloads

Use the on_payload callback in StreamOptions to inspect the request payload sent to the provider:

use std::{future::Future, pin::Pin, sync::Arc};

let options = StreamOptions {
    on_payload: Some(Arc::new(|payload, _model| {
        Box::pin(async move {
            println!("{}", serde_json::to_string_pretty(&payload).unwrap());
            Some(payload)
        }) as Pin<Box<dyn Future<Output = Option<serde_json::Value>> + Send>>
    })),
    ..Default::default()
};

Supported by stream, complete, stream_simple, and complete_simple.

Use on_response to capture raw HTTP metadata (status, headers) without logging full bodies:

use elph_ai::ProviderResponse;
use elph_ai::api::common::wrap_on_response;

let options = StreamOptions {
    on_response: Some(wrap_on_response(|response: ProviderResponse, _model| {
        Box::pin(async move {
            println!("status {}", response.status);
        })
    })),
    ..Default::default()
};

HTTP and WebSocket Proxies

Outbound HTTP(S) provider traffic respects standard proxy environment variables, including values supplied through StreamOptions.env / stored credential env maps:

• HTTP_PROXY, HTTPS_PROXY, ALL_PROXY — must be http:// or https:// URLs (SOCKS and PAC are not supported)
• NO_PROXY — comma- or whitespace-separated hostnames; prefix with . or * for suffix/wildcard matches; optional :port

WebSocket URLs (ws://, wss://) map to http:// / https:// for proxy rule lookup. OpenAI Codex WebSocket transport tunnels through HTTPS proxies (CONNECT + nested TLS). See tests/http_proxy.rs and tests/codex_websocket_proxy.rs.

Custom Providers

Build providers with create_provider():

use elph_ai::{CreateProviderOptions, ProviderApi, ProviderAuth, create_provider, env_api_key_auth};
use elph_ai::providers::adapter::openai_completions_api;

let provider = create_provider(CreateProviderOptions {
    id: "my-llm".into(),
    name: Some("My LLM".into()),
    base_url: Some("http://localhost:11434/v1".into()),
    headers: None,
    auth: ProviderAuth {
        api_key: Some(env_api_key_auth("API key", vec!["MY_LLM_API_KEY"])),
        oauth: None,
    },
    models: my_models,
    refresh_models: None, // or Some(Arc::new(|| Box::pin(async { ... })))
    api: ProviderApi::Single(openai_completions_api()),
});

Call API implementations directly from elph_ai::api for lower-level control, or register custom providers on a Models collection.

Faux Provider for Tests

faux_provider() builds an in-memory provider with scripted responses:

use elph_ai::{
    create_models, faux_assistant_message, faux_provider, faux_text, faux_thinking, faux_tool_call,
    FauxResponseStep, StopReason,
};
use serde_json::json;

let faux = faux_provider(Default::default());
let mut models = create_models(None);
models.set_provider(faux.provider.clone());

let model = faux.provider.get_models()[0].clone();
faux.set_responses(vec![FauxResponseStep::Static(faux_assistant_message(
    vec![
        faux_thinking("Need to inspect package metadata first."),
        faux_tool_call("echo", json!({ "text": "package.json" }), None),
    ],
    Some(StopReason::ToolUse),
))]);

Notes:

• Responses are consumed from a queue in request order
• An empty queue returns an assistant error: "No more faux responses queued"
• Use set_responses() to replace the queue and append_responses() to extend it
• Tool call arguments stream incrementally via ToolcallDelta events

See tests/faux_provider.rs for integration coverage.

Cross-Provider Handoffs

The library supports seamless handoffs between providers within the same conversation. When messages from one provider are sent to another, transform_messages adapts them for compatibility:

• User and tool result messages pass through unchanged
• Assistant messages from the same provider/API are preserved as-is
• Assistant messages from different providers have thinking blocks converted to <thinking> tagged text
• Tool calls and regular text are preserved unchanged

use elph_ai::providers::{anthropic_provider, openai_provider};

let mut models = create_models(None);
models.set_provider(anthropic_provider());
models.set_provider(openai_provider());
// register additional providers as needed

let mut context = Context { messages: vec![], system_prompt: None, tools: None };

let claude = models.get_model("anthropic", "claude-sonnet-4-5").unwrap();
context.messages.push(Message::User { /* ... */ });
context.messages.push(models.complete_simple(&claude, &context, None).await);

let gpt = models.get_model("openai", "gpt-5-mini").unwrap();
context.messages.push(Message::User { /* ... */ });
context.messages.push(models.complete(&gpt, &context, None).await);

See tests/transform_messages.rs.

Context Serialization

Context, Message, and AssistantMessage derive Serialize/Deserialize. Contexts are plain JSON-friendly structs you can persist, send over the wire, and resume with a different model:

let json = serde_json::to_string(&context)?;
let restored: Context = serde_json::from_str(&json)?;
let response = models.complete(&other_model, &restored, None).await;

OAuth Providers

Built-in OAuth flows are available for Anthropic, GitHub Copilot, and OpenAI Codex via elph_ai::auth::oauth:

use elph_ai::auth::oauth::{login_anthropic, register_oauth_provider, anthropic_oauth};
use std::sync::Arc;

register_oauth_provider(anthropic_oauth());
let tokens = login_anthropic(&callbacks).await?;

Use get_oauth_api_key(), refresh_oauth_token(), and the CredentialStore to persist tokens across sessions.

OpenAI Codex Transport

OpenAI Codex models (openai-codex-responses API) support SSE and WebSocket transports with automatic fallback when connection limits are hit. Collection-level models.stream() defaults to auto (WebSocket with cached context when session_id is set, SSE fallback on limit errors).

For explicit transport control, call the API module directly:

use elph_ai::api::codex_transport::CodexTransport;
use elph_ai::api::{OpenAICodexResponsesApi, OpenAICodexResponsesOptions};

let api = OpenAICodexResponsesApi;
let _stream = api.stream_with_options(
    &model,
    &context,
    OpenAICodexResponsesOptions {
        transport: CodexTransport::WebSocketCached,
        base: StreamOptions {
            session_id: Some("my-session".into()),
            env: Some(proxy_env), // HTTP_PROXY / NO_PROXY for corporate networks
            ..Default::default()
        },
        ..Default::default()
    },
);

CodexTransport values: Auto, Sse, WebSocket, WebSocketCached. Debug helpers (get_codex_websocket_debug_stats, close_codex_websocket_sessions) are exported from the crate root.

Vertex AI

Vertex AI supports either an API key or Application Default Credentials:

# Local ADC
gcloud auth application-default login
export GOOGLE_CLOUD_PROJECT="my-project"
export GOOGLE_CLOUD_LOCATION="us-central1"

# CI/Production
export GOOGLE_APPLICATION_CREDENTIALS="/path/to/service-account.json"

Development

Regenerating Model Catalogs

Chat and image model catalogs are generated from pi-ai scripts:

# From the repo root (requires upstream catalog checkout and npm deps)
make generate-models ELPH_AI_CATALOG_DIR=/path/to/catalog/packages/ai

# Or directly:
cargo run -p elph-ai --bin generate-models -- all --catalog-dir /path/to/catalog/packages/ai

# Convert existing catalog output without re-running npm scripts:
make generate-models ELPH_AI_CATALOG_DIR=/path/to/catalog/packages/ai ARGS="--skip-scripts"

Subcommands:

Command	Catalog npm script	Output
chat	generate-models	models/*.json + src/models/catalog.rs
image	generate-image-models	models/images/*.json + src/images/models.rs
test-image	generate-test-image	tests/data/red-circle.png
all	all of the above	everything

Adding a New Provider

1. Types (src/types/mod.rs) — add API/provider identifiers and options if needed
2. API (src/api/<api-id>.rs) — implement stream / stream_simple for new wire protocols
3. Catalog — add fetch logic to the upstream catalog generate-models script, then run make generate-models
4. Provider factory (src/providers/builtin.rs) — wire catalog + auth + API adapter; register in builtin_providers()
5. Tests (tests/) — streaming, tools, auth, cross-provider handoff as applicable

Running Tests

# Unit and integration tests (default — skips #[ignore] live tests)
cargo nextest run -p elph-ai

# Run all tests including live provider tests (requires API keys)
cargo nextest run -p elph-ai -- --ignored

# Individual live test binaries
cargo nextest run -p elph-ai --test e2e_live -- --ignored
cargo nextest run -p elph-ai --test abort_live -- --ignored
cargo nextest run -p elph-ai --test cross_provider_handoff_live -- --ignored
cargo nextest run -p elph-ai --test openrouter_cache_write_live -- --ignored
cargo nextest run -p elph-ai --test tool_call_id_normalization_live -- --ignored

Integration tests mirror upstream coverage: provider auth, SSE parsing and mid-stream abort, HTTP/WebSocket proxy routing, tool schemas, retry/overflow, OAuth, Bedrock endpoint resolution, Codex WebSocket transport, faux provider, and more under tests/.

License

Licensed under the MIT License.