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a2a-platform
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README.md Normal file
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# chart-agent
A new A2A agent
This project was scaffolded with `a2a init`. It starts as a DeepAgents-backed
A2A agent that uses a scoped platform LLM grant from `ctx.llm`.
The same `ctx.llm` path is used if you intentionally switch the agent to
`LLMProvisioning.CALLER_PROVIDED` for BYOK: the platform forwards the caller's
selected credentials as `ctx.llm`. Trusted platform agents may use
`LLMProvisioning.PLATFORM_OR_CALLER_PROVIDED` to prefer caller creds and fall
back to a platform grant. Do not read provider keys, LiteLLM master keys,
`OPENAI_API_KEY`, or `A2A_LITELLM_KEY` directly in agent code, and do not
substitute fake fallback API keys when `ctx.llm.api_key` is empty.
## Durable Files
A2A Cloud workspaces are grant-scoped and backed by MinIO. Files become durable
when your agent uses one of the platform-owned file paths:
- `ctx.workspace` for direct workspace reads and writes
- `ctx.write_artifact(...)` for explicit output artifacts
- `ctx.sandbox` for commands that read or write files in a sandbox
- `ctx.workspace_backend()` for framework file tools such as DeepAgents
DeepAgents has its own built-in file tools (`write_file`, `read_file`,
`edit_file`). Without an A2A backend, those tools write into LangGraph state
only, so files can appear to the agent but never reach MinIO or `/workspace`.
Keep this line when building DeepAgents graphs:
```python
backend = ctx.workspace_backend()
return create_deep_agent(model=model, backend=backend, tools=[...])
```
Invoke DeepAgents graphs with the starter recursion budget:
```python
state = await graph.ainvoke(
{"messages": [{"role": "user", "content": prompt}]},
config={"recursion_limit": 500},
)
```
The backend respects the caller's grant. In handoffs, generated files should go
through `ctx.workspace_backend()`, `ctx.write_artifact(...)`, or a sandbox helper
so they are mirrored to the caller workspace instead of becoming private virtual
files.
For stable, human-readable paths, write intentional outputs to
`/workspace/outputs/...` or `ctx.write_artifact(...)`. If sandboxed code writes
to process-local paths such as `/tmp/result.csv`, `/root`, or `/app`, the
platform captures changed rootfs files under `outputs/rootfs-captures/...` so
the caller can still download and inspect them.
When a skill needs to run real code, render media, convert files, or call a
CLI that writes outputs, use the workspace-mounted sandbox helpers:
```python
result = await ctx.workspace_shell(
"python script.py --out /tmp/result.txt",
image="python:3.11-slim",
timeout_seconds=120,
)
```
Do not rely on `asyncio.create_subprocess_exec(...)` for durable outputs. A
plain subprocess runs in the agent container, which is not mounted to the
caller workspace; files it creates in `/tmp` or the image filesystem can vanish
after the request. Use the sandbox helpers for any file-producing toolchain.
## DeepAgents Skills
If this project grows reusable workflow knowledge, add source-controlled skill
folders under `skills/<skill-name>/SKILL.md`. The starter's `_seed_runtime_skills`
helper copies those packaged skills into the invocation workspace and passes the
resulting source path to `create_deep_agent(..., skills=[...])`, which is how
DeepAgents discovers skills with progressive disclosure.
## Run Locally
```bash
python -m pip install -r requirements.txt
a2a dev
a2a test
a2a test --invoke --skill summarize --args-json '{"text":"hello"}'
a2a card
```
`a2a dev` loads `.env.local`, creates `.a2a/workspace/{inputs,outputs}`, serves
the same HTTP invoke/card/MCP endpoints as production, and hot reloads local
code. Files written through `ctx.workspace_backend()` land under
`.a2a/workspace/outputs` before you deploy.
## Auth
The template is public by default (`auth_model = NoAuth`). To require the
caller's app login, declare a typed auth model and resolver in `agent.py`.
Resolvers receive the inbound bearer token and return the principal exposed as
`ctx.auth`.
```python
from a2a_pack import JWTAuth, OIDCUserInfoAuthResolver
auth_model = JWTAuth
auth_resolver = OIDCUserInfoAuthResolver(
"https://auth.example.com/oauth2/userinfo",
auth_model=JWTAuth,
)
```
For homegrown auth or SAML-backed apps, expose a bearer-token `/me` or
`/introspect` endpoint and use the same resolver contract.
## Deploy
```bash
a2a deploy
```

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# Project identity for `a2a deploy`. Most metadata (resources, scopes,
# secrets, workspace, etc.) lives on the Python class — this file only
# tells the CLI how to find it.
name: chart-agent
version: 0.1.0
entrypoint: agent:ChartAgent
expose:
public: true
frontend:
path: frontend
build: npm run build
dist: dist
mount: /app
auth: inherit

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"""chart-agent agent.
Starter stack:
- DeepAgents for tool-calling orchestration
- A2A platform LLM grants via ctx.llm
- A tiny model-call middleware hook you can replace with tracing,
routing, rate limits, or policy checks
"""
from __future__ import annotations
import json
from pathlib import Path
from typing import Any
from pydantic import BaseModel
from a2a_pack import (
A2AAgent,
LLMProvisioning,
NoAuth,
Pricing,
RunContext,
WorkspaceAccess,
WorkspaceMode,
skill,
)
from a2a_pack.context import LLMCreds
class ChartAgentConfig(BaseModel):
pass
SYSTEM_PROMPT = """\
You are a compact tool-calling agent.
Use the text_stats tool when the user asks about text, counts, summaries,
or anything where exact length/word numbers would help. Mention tool results
briefly instead of dumping raw JSON.
"""
RUNTIME_SKILLS_DIR = "chart-agent/.deepagents/skills/"
DEEPAGENTS_RECURSION_LIMIT = 500
class ChartAgent(A2AAgent[ChartAgentConfig, NoAuth]):
name = "chart-agent"
description = "A new A2A agent"
version = "0.1.0"
config_model = ChartAgentConfig
auth_model = NoAuth
# Default hosted generated agents to platform LLM grants. The runtime
# exposes the scoped LiteLLM token through ctx.llm, so agent code never
# reads provider keys, LiteLLM master keys, or OPENAI_API_KEY directly.
# Use CALLER_PROVIDED only for explicit BYOK agents; reserve
# PLATFORM_OR_CALLER_PROVIDED for trusted platform/meta agents.
llm_provisioning = LLMProvisioning.PLATFORM
pricing = Pricing(
price_per_call_usd=0.0,
caller_pays_llm=False,
notes="Starter agent uses a scoped platform LLM grant via ctx.llm.",
)
workspace_access = WorkspaceAccess.dynamic(
max_files=64,
allowed_modes=(WorkspaceMode.READ_ONLY, WorkspaceMode.READ_WRITE_OVERLAY),
require_reason=False,
)
tools_used = ("deepagents", "langchain")
@skill(description="Ask the starter DeepAgent to answer with tool calls when useful")
async def ask(self, ctx: RunContext[NoAuth], prompt: str) -> str:
creds = ctx.llm
await ctx.emit_progress(f"llm: {creds.model} via {creds.source}")
if not creds.api_key:
return (
"LLM credentials were not available for this run. Hosted "
"generated agents should receive a platform LLM grant; for "
"local --invoke runs set A2A_LITELLM_KEY or AGENT_LLM_KEY."
)
graph = self._build_deep_agent(ctx=ctx, creds=creds)
state = await graph.ainvoke(
{"messages": [{"role": "user", "content": prompt}]},
config={"recursion_limit": DEEPAGENTS_RECURSION_LIMIT},
)
await ctx.emit_progress("deepagent finished")
return _last_message_text(state)
def _build_deep_agent(
self,
*,
ctx: RunContext[NoAuth],
creds: LLMCreds,
) -> Any:
# Lazy imports keep `a2a card` usable before local dependencies are
# installed. `a2a deploy` installs requirements.txt during the build.
from deepagents import create_deep_agent
from langchain.agents.middleware import wrap_model_call
from langchain_core.tools import tool
from langchain_openai import ChatOpenAI
@tool
def text_stats(text: str) -> str:
"""Return exact word, character, and line counts for text."""
words = [part for part in text.split() if part.strip()]
return json.dumps(
{
"characters": len(text),
"words": len(words),
"lines": len(text.splitlines()) or 1,
}
)
@wrap_model_call
async def log_model_call(request: Any, handler: Any) -> Any:
messages = request.state.get("messages", [])
print(
"[middleware] model_call "
f"model={creds.model} source={creds.source} messages={len(messages)}"
)
return await handler(request)
model_kwargs: dict[str, Any] = {
"model": creds.model,
"base_url": creds.base_url,
# For CALLER_PROVIDED this is the caller's forwarded key. For
# PLATFORM this is the short-lived A2A LiteLLM grant token. Do not
# substitute provider keys, LiteLLM master keys, or fake fallback
# values here.
"api_key": creds.api_key,
}
if creds.temperature_mode != "omit":
model_kwargs["temperature"] = (
creds.temperature if creds.temperature is not None else 0.0
)
if creds.extra_body:
model_kwargs["extra_body"] = dict(creds.extra_body)
model = ChatOpenAI(**model_kwargs)
backend = ctx.workspace_backend()
skill_sources = _seed_runtime_skills(backend, ctx)
return create_deep_agent(
model=model,
backend=backend,
skills=skill_sources or None,
tools=[text_stats],
middleware=[log_model_call],
system_prompt=SYSTEM_PROMPT,
)
def _runtime_skills_root(ctx: RunContext[Any]) -> str:
workspace = getattr(ctx, "_workspace", None)
prefixes = tuple(getattr(workspace, "write_prefixes", ()) or ())
if not prefixes:
outputs_prefix = getattr(workspace, "outputs_prefix", None)
prefixes = (outputs_prefix or "outputs/",)
prefix = str(prefixes[0]).strip("/")
return f"/{prefix}/{RUNTIME_SKILLS_DIR}" if prefix else f"/{RUNTIME_SKILLS_DIR}"
def _seed_runtime_skills(backend: Any, ctx: RunContext[Any]) -> list[str]:
"""Copy packaged DeepAgents skills into the invocation workspace.
DeepAgents loads skills from its backend, while source-controlled
``skills/`` folders live in the image. This bridge lets generated agents
ship reusable SKILL.md bundles without giving up durable A2A workspace
files.
"""
root = Path(__file__).parent / "skills"
if not root.exists():
return []
runtime_skills_root = _runtime_skills_root(ctx)
uploads: list[tuple[str, bytes]] = []
for path in root.rglob("*"):
if path.is_file():
rel = path.relative_to(root).as_posix()
uploads.append((runtime_skills_root + rel, path.read_bytes()))
if uploads:
backend.upload_files(uploads)
return [runtime_skills_root]
return []
def _last_message_text(state: dict[str, Any]) -> str:
messages = state.get("messages") or []
if not messages:
return json.dumps(state, default=str)
content = getattr(messages[-1], "content", None)
if isinstance(content, str):
return content
if isinstance(content, list):
parts: list[str] = []
for item in content:
if isinstance(item, dict):
text = item.get("text") or item.get("content")
if text:
parts.append(str(text))
elif item:
parts.append(str(item))
return "\n".join(parts) if parts else json.dumps(content, default=str)
return str(content or messages[-1])

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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>chart-agent app</title>
</head>
<body>
<div id="root"></div>
<script type="module" src="/src/main.jsx"></script>
</body>
</html>

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{
"name": "chart-agent-frontend",
"private": true,
"version": "0.1.0",
"type": "module",
"scripts": {
"dev": "vite --host 0.0.0.0 --port 5173",
"build": "vite build",
"preview": "vite preview --host 0.0.0.0"
},
"dependencies": {
"react": "^18.3.1",
"react-dom": "^18.3.1"
},
"devDependencies": {
"@vitejs/plugin-react": "^4.3.4",
"vite": "^5.4.0"
}
}

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import { useEffect, useMemo, useState } from "react";
import {
callSkill,
loadAgentConfig,
loadSession,
sampleArgs,
} from "./a2a.js";
export function App() {
const [config, setConfig] = useState(null);
const [session, setSession] = useState(null);
const [selectedSkillName, setSelectedSkillName] = useState("");
const [argsText, setArgsText] = useState("{}");
const [result, setResult] = useState(null);
const [error, setError] = useState(null);
const [running, setRunning] = useState(false);
useEffect(() => {
loadAgentConfig()
.then((data) => {
setConfig(data);
const firstSkill = data.skills?.[0];
if (firstSkill) {
setSelectedSkillName(firstSkill.name);
setArgsText(JSON.stringify(sampleArgs(firstSkill), null, 2));
}
return loadSession(data).catch(() => null);
})
.then((sessionData) => setSession(sessionData))
.catch((err) => setError(err.message || String(err)));
}, []);
const selectedSkill = useMemo(
() => config?.skills?.find((skill) => skill.name === selectedSkillName),
[config, selectedSkillName],
);
function selectSkill(skill) {
setSelectedSkillName(skill.name);
setArgsText(JSON.stringify(sampleArgs(skill), null, 2));
setResult(null);
setError(null);
}
async function runSkill(event) {
event.preventDefault();
if (!config || !selectedSkill) return;
setRunning(true);
setError(null);
setResult(null);
try {
const args = JSON.parse(argsText || "{}");
const data = await callSkill(config, selectedSkill.name, args);
setResult(data);
} catch (err) {
setError(err.message || String(err));
} finally {
setRunning(false);
}
}
if (!config) {
return (
<main className="loading">
<p>{error || "Loading A2A agent contract..."}</p>
</main>
);
}
return (
<main className="app-shell">
<aside className="sidebar">
<div>
<p className="eyebrow">A2A packed app</p>
<h1>chart-agent</h1>
<p className="agent-meta">
{config.agent.name} v{config.agent.version}
</p>
</div>
<nav className="skill-list" aria-label="Agent skills">
{(config.skills || []).map((skill) => (
<button
className={skill.name === selectedSkillName ? "skill active" : "skill"}
key={skill.name}
onClick={() => selectSkill(skill)}
type="button"
>
<span>{skill.name}</span>
<small>{skill.stream ? "streaming" : "request"}</small>
</button>
))}
</nav>
<div className="session">
<span>{session?.authenticated ? "Signed in" : "Local session"}</span>
<strong>{session?.user?.email || session?.org?.slug || "dev@example.local"}</strong>
</div>
</aside>
<section className="workbench">
<header className="toolbar">
<div>
<p className="eyebrow">Skill runner</p>
<h2>{selectedSkill?.name || "No skills found"}</h2>
</div>
<a href={config.docs.base} rel="noreferrer" target="_blank">
Docs
</a>
</header>
{selectedSkill ? (
<form className="runner" onSubmit={runSkill}>
<label>
Arguments JSON
<textarea
spellCheck="false"
value={argsText}
onChange={(event) => setArgsText(event.target.value)}
/>
</label>
<button disabled={running} type="submit">
{running ? "Running..." : `Run ${selectedSkill.name}`}
</button>
</form>
) : (
<p className="empty">Add a `@skill` to your agent to make it callable here.</p>
)}
<section className="panels">
<div className="panel">
<h3>Input schema</h3>
<pre>{JSON.stringify(selectedSkill?.input_schema || {}, null, 2)}</pre>
</div>
<div className="panel">
<h3>Result</h3>
<pre>{error || JSON.stringify(result, null, 2) || "No run yet."}</pre>
</div>
</section>
</section>
</main>
);
}

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export const CONFIG_URL = import.meta.env.DEV ? "/app/config.json" : "./config.json";
export async function requestJson(url, init = {}) {
const response = await fetch(url, { credentials: "same-origin", ...init });
const text = await response.text();
const data = text ? JSON.parse(text) : null;
if (!response.ok) {
const detail = data && (data.detail || data.message);
throw new Error(detail || `request failed: ${response.status}`);
}
return data;
}
export async function loadAgentConfig() {
return requestJson(CONFIG_URL);
}
export async function loadSession(config) {
return requestJson(config.endpoints.session);
}
export async function callSkill(config, skillName, args) {
if (config.auth?.invokeRequiresSession) {
const session = await loadSession(config);
if (!session?.authenticated) {
throw new Error("sign in required");
}
}
return requestJson(
`${config.endpoints.invoke}/${encodeURIComponent(skillName)}`,
{
method: "POST",
headers: { "content-type": "application/json" },
body: JSON.stringify({ arguments: args }),
},
);
}
export function sampleValue(schema) {
if (!schema || typeof schema !== "object") return null;
if ("default" in schema) return schema.default;
if ("const" in schema) return schema.const;
if (Array.isArray(schema.enum) && schema.enum.length) return schema.enum[0];
const type = Array.isArray(schema.type)
? schema.type.find((item) => item !== "null") || schema.type[0]
: schema.type;
if (type === "array") return [];
if (type === "boolean") return false;
if (type === "integer" || type === "number") return 0;
if (type === "string") return "";
const props = schema.properties || {};
if (type === "object" || Object.keys(props).length) {
const required = Array.isArray(schema.required) ? schema.required : Object.keys(props);
return Object.fromEntries(
required.map((key) => [key, sampleValue(props[key])]),
);
}
return null;
}
export function sampleArgs(skill) {
const schema = skill?.input_schema || skill?.inputSchema || {};
const value = sampleValue(schema);
return value && typeof value === "object" && !Array.isArray(value) ? value : {};
}

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import React from "react";
import { createRoot } from "react-dom/client";
import { App } from "./App.jsx";
import "./style.css";
createRoot(document.getElementById("root")).render(
<React.StrictMode>
<App />
</React.StrictMode>,
);

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:root {
color-scheme: dark;
font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
background: #090909;
color: #f5f5f5;
}
* {
box-sizing: border-box;
}
body {
margin: 0;
min-height: 100vh;
background: #090909;
}
button,
textarea {
font: inherit;
}
button {
cursor: pointer;
}
.loading {
min-height: 100vh;
display: grid;
place-items: center;
color: #b8b8b8;
}
.app-shell {
min-height: 100vh;
display: grid;
grid-template-columns: minmax(260px, 340px) 1fr;
}
.sidebar {
min-height: 100vh;
border-right: 1px solid #222;
background: #0d0d0d;
padding: 28px;
display: grid;
align-content: start;
gap: 28px;
}
.eyebrow {
margin: 0 0 10px;
color: #8bd8c6;
font-size: 12px;
letter-spacing: 0;
text-transform: uppercase;
}
h1,
h2,
h3,
p {
margin-top: 0;
}
h1 {
margin-bottom: 10px;
font-size: clamp(32px, 5vw, 56px);
line-height: 0.95;
letter-spacing: 0;
}
h2 {
margin-bottom: 0;
font-size: 30px;
letter-spacing: 0;
}
h3 {
margin-bottom: 12px;
color: #d7d7d7;
font-size: 14px;
letter-spacing: 0;
}
.agent-meta {
margin-bottom: 0;
color: #a6a6a6;
}
.skill-list {
display: grid;
gap: 10px;
}
.skill {
width: 100%;
min-height: 58px;
border: 1px solid #252525;
border-radius: 8px;
background: #121212;
color: #f3f3f3;
padding: 12px 14px;
display: flex;
align-items: center;
justify-content: space-between;
gap: 16px;
text-align: left;
}
.skill:hover,
.skill.active {
border-color: #5bb7a7;
background: #15201d;
}
.skill span {
overflow-wrap: anywhere;
}
.skill small {
color: #9d9d9d;
}
.session {
border: 1px solid #252525;
border-radius: 8px;
padding: 14px;
color: #a6a6a6;
display: grid;
gap: 4px;
}
.session strong {
color: #f3f3f3;
overflow-wrap: anywhere;
}
.workbench {
padding: 28px;
display: grid;
align-content: start;
gap: 22px;
}
.toolbar {
display: flex;
align-items: center;
justify-content: space-between;
gap: 18px;
}
.toolbar a,
.runner button {
border: 1px solid #e8e8e8;
border-radius: 7px;
background: #f4f4f4;
color: #111;
padding: 10px 14px;
text-decoration: none;
white-space: nowrap;
}
.runner {
display: grid;
gap: 12px;
}
.runner label {
display: grid;
gap: 10px;
color: #d7d7d7;
}
.runner textarea {
width: 100%;
min-height: 170px;
resize: vertical;
border: 1px solid #252525;
border-radius: 8px;
background: #070707;
color: #eeeeee;
padding: 14px;
line-height: 1.5;
font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}
.runner button {
justify-self: start;
}
.runner button:disabled {
cursor: wait;
opacity: 0.72;
}
.panels {
display: grid;
grid-template-columns: repeat(2, minmax(0, 1fr));
gap: 16px;
}
.panel {
min-width: 0;
border: 1px solid #252525;
border-radius: 8px;
padding: 16px;
background: #0d0d0d;
}
pre {
min-height: 260px;
max-height: 420px;
margin: 0;
overflow: auto;
color: #dcdcdc;
line-height: 1.5;
font-size: 13px;
font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}
.empty {
color: #aaa;
}
@media (max-width: 820px) {
.app-shell {
grid-template-columns: 1fr;
}
.sidebar {
min-height: auto;
border-right: 0;
border-bottom: 1px solid #222;
}
.panels {
grid-template-columns: 1fr;
}
.toolbar {
align-items: flex-start;
flex-direction: column;
}
}

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import react from "@vitejs/plugin-react";
import { defineConfig } from "vite";
const agent = process.env.A2A_DEV_AGENT_URL || "http://127.0.0.1:8000";
export default defineConfig({
base: "./",
plugins: [react()],
server: {
proxy: {
"/app": agent,
"/invoke": agent,
"/auth": agent,
"/mcp": agent,
"/.well-known": agent,
},
},
});

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# a2a-pack is auto-installed by the deploy build.
# These starter deps power the DeepAgents tool-calling example in agent.py.
deepagents>=0.5.0
langchain>=0.3
langchain-openai>=0.2
langgraph>=0.6