agentapi

Any-to-any AI protocol bridge. Point any SDK (OpenAI, Anthropic, Gemini) at it — requests route to any backend (Kilo Code, opencode, Claude CLI, Anthropic API, Gemini, Ollama, AWS Bedrock) and stream back in the wire format the client expects.

Quickstart

npx agentapi                    # defaults: :4800, kilo :4780, opencode :4790
npx agentapi --port 8080        # custom port

Then point any AI SDK at http://localhost:4800.

Demo

• Built-in: http://localhost:4800/ when agentapi is running (no CORS, full streaming)
• GH Pages: https://anentrypoint.github.io/agentapi (browser-blocked from loopback by Chrome PNA — use built-in demo instead)

Usage

OpenAI SDK (any backend)

import OpenAI from 'openai';
const client = new OpenAI({ baseURL: 'http://localhost:4800/v1', apiKey: 'none' });

const stream = await client.chat.completions.create({
  model: 'kilo/x-ai/grok-code-fast-1:optimized:free',
  messages: [{ role: 'user', content: 'hi' }],
  stream: true,
});
for await (const chunk of stream) process.stdout.write(chunk.choices[0]?.delta?.content || '');

Anthropic SDK (any backend)

import Anthropic from '@anthropic-ai/sdk';
const client = new Anthropic({ baseURL: 'http://localhost:4800', apiKey: 'none' });

const stream = await client.messages.create({
  model: 'gemini-2.0-flash',
  messages: [{ role: 'user', content: 'hi' }],
  max_tokens: 1024,
  stream: true,
});
for await (const ev of stream) { /* standard Anthropic SDK events */ }

Gemini SDK (any backend)

import { GoogleGenerativeAI } from '@google/generative-ai';
const genai = new GoogleGenerativeAI({ baseUrl: 'http://localhost:4800' });
const model = genai.getGenerativeModel({ model: 'kilo/kilo-auto/free' });
const result = await model.generateContentStream('hi');

Fallback chains

Combine providers with predictable fallback. xstate-driven FSM under the hood — every transition is observable.

import { chain, fallback } from 'agentapi';

// Plain array — falls back on error (default)
const c = chain(['claude/sonnet', 'gemini/flash', 'ollama/llama3']);
const reply = await c.chat({ messages: [{ role: 'user', content: 'hi' }] });

// Per-link config — each link can override anything
chain([
  { model: 'claude/sonnet', timeout: 5000 },
  { model: 'gemini/flash', temperature: 0.3 },
  { model: 'ollama/llama3', system: 'Be brief.' },
], {
  fallbackOn: ['error', 'timeout', 'rate_limit', 'empty', 'content_policy'],
  onFallback: ({ from, to, reason }) => console.log(`${from} → ${to} (${reason})`),
});

// Builder
fallback('claude/sonnet')
  .then('gemini/flash')
  .then('ollama/llama3')
  .timeout(8000)
  .fallbackOn(['error', 'timeout', 'empty'])
  .build();

// Streaming works identically
for await (const ev of c.stream({ messages: [...] })) { /* ... */ }

Named chains

Define once in ~/.thebird/config.json (or THEBIRD_CONFIG):

{
  "chains": {
    "prod": {
      "links": [
        { "model": "anthropic/claude-sonnet-4-6", "timeout": 5000 },
        { "model": "gemini/gemini-2.5-pro" },
        { "model": "ollama/llama3.2" }
      ],
      "defaults": { "fallbackOn": ["error", "timeout", "empty"] }
    }
  }
}

Then use it from any client by model id chain/prod:

curl http://localhost:4800/v1/chat/completions -d '{"model":"chain/prod","messages":[...]}'

await chain('prod').chat({ messages: [...] });

• agentapi --list-chains — list defined chains.
• GET /debug/chains — defined chains + last 50 runs (state, links tried, reasons).

Model prefixes

| prefix | backend | notes | |--------|---------|-------| | kilo/ | Kilo Code ACP | free models available | | opencode/ | opencode ACP | free models available | | claude/ | Claude Code CLI | local OAuth, no API key needed | | anthropic/ | Anthropic API direct | requires ANTHROPIC_API_KEY | | gemini/ | Google Gemini API | requires GEMINI_API_KEY | | ollama/ | Local Ollama | requires Ollama running at OLLAMA_URL | | bedrock/ | AWS Bedrock Converse | requires AWS credentials | | openai/ | OpenAI direct | OPENAI_API_KEY | | groq/ | Groq | GROQ_API_KEY | | openrouter/ | OpenRouter | OPENROUTER_API_KEY | | together/ | Together AI | TOGETHER_API_KEY | | deepseek/ | DeepSeek | DEEPSEEK_API_KEY | | xai/ | xAI (Grok) | XAI_API_KEY | | cerebras/ | Cerebras | CEREBRAS_API_KEY | | perplexity/ | Perplexity | PERPLEXITY_API_KEY | | mistral/ | Mistral La Plateforme | MISTRAL_API_KEY | | fireworks/ | Fireworks AI | FIREWORKS_API_KEY |

Brand prefixes are pure passthrough to that vendor's OpenAI-compatible endpoint — full streaming, tool-calling, whatever the brand supports flows through unchanged.

Bare model IDs (no prefix) route to kilo.

Example model IDs

• kilo/x-ai/grok-code-fast-1:optimized:free — free, default
• kilo/kilo-auto/free
• opencode/minimax-m2.5-free
• claude/sonnet, claude/haiku, claude/opus
• anthropic/claude-sonnet-4-6
• gemini/gemini-2.0-flash, gemini/gemini-2.5-pro
• ollama/llama3.2:latest (any locally pulled model)
• bedrock/anthropic.claude-3-5-sonnet-20241022-v2:0

Endpoints

OpenAI-compatible

• POST /v1/chat/completions — streaming + non-streaming
• GET /v1/models — live-probed list across all backends

Anthropic-compatible

• POST /v1/messages — Anthropic Messages API drop-in, any backend
• POST /v1/messages/count_tokens — token estimator (heuristic, no API call)

Embeddings

• POST /v1/embeddings — OpenAI-format embeddings, prefix-routed (openai/, together/, mistral/, voyage/, deepseek/)
• POST /v1beta/models/:model:embedContent — Gemini-format embeddings (proxies Google)
• POST /v1beta/models/:model:countTokens — Gemini-format token count (heuristic)

Passthrough endpoints (vendor-prefixed)

• POST /v1/images/generations — openai/, together/
• POST /v1/moderations — openai/
• POST /v1/rerank — cohere/, voyage/, together/
• POST /v1/audio/speech — openai/, groq/

Operations

• GET /metrics — Prometheus exposition (request counters, latency summary, uptime)
• Optional bearer auth: set AGENTAPI_API_KEY=<secret>; clients must send Authorization: Bearer <secret> (or x-api-key). /health, /metrics, /debug/*, and demo assets stay public.

CLI flags

npx agentapi --probe          # show which provider env vars are set
npx agentapi --list-brands    # list supported OpenAI-compat brand prefixes

Gemini-compatible

• POST /v1beta/models/:model:streamGenerateContent — Gemini streaming API drop-in
• POST /v1beta/models/:model:generateContent — Gemini non-streaming
• GET /v1beta/models — model list in Gemini format

Observability

• GET /debug/providers — live probe all backends with latency
• GET /debug/config — active config (secrets redacted)
• POST /debug/translate — echo internal event stream for any {from,to,provider,...} request
• GET /health

SDK

Programmatic, server-free. Pass a model string, get events or buffered response back; built-in fallback chains.

const { chat, stream, chain } = require('agentapi');

// One-shot. Model prefix selects backend automatically.
const r = await chat({
  model: 'groq/llama-3.3-70b-versatile',
  messages: [{ role: 'user', content: 'hi' }],
});
console.log(r.choices[0].message.content);

// Streaming. Output format selectable via `output: 'openai' | 'anthropic' | 'gemini' | 'events'`.
for await (const ev of stream({
  model: 'anthropic/claude-sonnet-4-6',
  messages: [{ role: 'user', content: 'hi' }],
  output: 'events',
})) {
  if (ev.type === 'text-delta') process.stdout.write(ev.textDelta);
}

Fallback chains

const fast = chain([
  'groq/llama-3.3-70b-versatile',          // try Groq first (cheap, fast)
  'openrouter/auto',                        // fall back to OpenRouter
  'anthropic/claude-sonnet-4-6',            // finally Anthropic direct
]);

const r = await fast.chat({ messages: [{ role: 'user', content: 'hi' }] });

// Streaming fallback — first model that produces an event "wins" the stream.
for await (const ev of fast.stream({ messages: [{ role: 'user', content: 'hi' }] })) {
  if (ev.type === 'text-delta') process.stdout.write(ev.textDelta);
}

Each link is tried in order. A link "fails" if it throws (missing env var, network error, upstream non-2xx). Once a link emits its first event, it owns the rest of the stream — no mid-stream switching. If all links fail, the last error is rethrown.

resolveModel(modelString) returns { provider, model, env, url?, prefix } — useful for inspecting routing without invoking.

Programmatic translate API

const { translate, buffer } = require('agentapi/lib/translate');

// Stream any format through any provider, get any format back
for await (const ev of translate({ from: 'openai', to: 'anthropic', provider: 'gemini', model: 'gemini-2.0-flash', messages: [...] })) {
  if (ev.type === 'sse') process.stdout.write(ev.raw);
}

// Buffer to response object
const response = await buffer({ from: 'anthropic', to: 'openai', provider: 'ollama', model: 'llama3.2', messages: [...] });

Supported from/to formats: anthropic, openai, gemini, acp, mistral, cohere, ollama, bedrock

Supported provider values: gemini, openai-compat, acp, cloud, router, anthropic, ollama, bedrock

Internal event model

All formats convert through a common event stream:

| event type | fields | maps from | |-----------|--------|-----------| | start-step | — | message start | | text-delta | textDelta | token | | reasoning-delta | reasoningDelta | thinking / reasoning_content | | tool-call | toolCallId, toolName, args | function call | | tool-result | toolCallId, toolName, result | tool output | | finish-step | finishReason | stop / tool-calls / error | | error | error | stream error |

Config

CLI flags or env:

| flag | env | default | |------|-----|---------| | --port | PORT | 4800 | | --kilo <url> | ACP_KILO_URL | http://localhost:4780 | | --opencode <url> | ACP_OPENCODE_URL | http://localhost:4790 | | --claude-bin <path> | CLAUDE_BIN | claude | | — | ANTHROPIC_API_KEY | — | | — | GEMINI_API_KEY | — | | — | OLLAMA_URL | http://localhost:11434 | | — | AWS_ACCESS_KEY_ID | — | | — | AWS_SECRET_ACCESS_KEY | — | | — | AWS_REGION | us-east-1 | | — | AWS_SESSION_TOKEN | — |

Why

The AI provider landscape is fragmented: each has its own wire protocol, streaming format, and auth scheme. agentapi normalises all of them through a shared internal event model — any input wire format → internal events → any output wire format → any provider backend. One bridge, every direction.

License

MIT