Get started with Claude Managed Agents

Concept	Description
Agent	The model, system prompt, tools, MCP servers, and skills
Environment	A configured container template (packages, network access)
Session	A running agent instance within an environment, performing a specific task and generating outputs
Events	Messages exchanged between your application and the agent (user turns, tool results, status updates)

Concept	Description
Agent	The model, system prompt, tools, MCP servers, and skills
Environment	A configured container template (packages, network access)
Session	A running agent instance within an environment, performing a specific task and generating outputs
Events	Messages exchanged between your application and the agent (user turns, tool results, status updates)

Create an agent

Create an agent that defines the model, system prompt, and available tools.

set -euo pipefail

agent=$(
  curl -sS --fail-with-body https://api.anthropic.com/v1/agents \
    -H "x-api-key: $ANTHROPIC_API_KEY" \
    -H "anthropic-version: 2023-06-01" \
    -H "anthropic-beta: managed-agents-2026-04-01" \
    -H "content-type: application/json" \
    -d @- <<'EOF'
{
  "name": "Coding Assistant",
  "model": "claude-sonnet-4-6",
  "system": "You are a helpful coding assistant. Write clean, well-documented code.",
  "tools": [
    {"type": "agent_toolset_20260401"}
  ]
}
EOF
)

AGENT_ID=$(jq -er '.id' <<<"$agent")
AGENT_VERSION=$(jq -er '.version' <<<"$agent")

echo "Agent ID: $AGENT_ID, version: $AGENT_VERSION"

The agent_toolset_20260401 tool type enables the full set of pre-built agent tools (bash, file operations, web search, and more). See Tools for the complete list and per-tool configuration options.

Save the returned agent.id. You'll reference it in every session you create.

Create an environment

An environment defines the container where your agent runs.

environment=$(
  curl -sS --fail-with-body https://api.anthropic.com/v1/environments \
    -H "x-api-key: $ANTHROPIC_API_KEY" \
    -H "anthropic-version: 2023-06-01" \
    -H "anthropic-beta: managed-agents-2026-04-01" \
    -H "content-type: application/json" \
    -d @- <<'EOF'
{
  "name": "quickstart-env",
  "config": {
    "type": "cloud",
    "networking": {"type": "unrestricted"}
  }
}
EOF
)

ENVIRONMENT_ID=$(jq -er '.id' <<<"$environment")

echo "Environment ID: $ENVIRONMENT_ID"

Save the returned environment.id. You'll reference it in every session you create.

Start a session

Create a session that references your agent and environment.

session=$(
  curl -sS --fail-with-body https://api.anthropic.com/v1/sessions \
    -H "x-api-key: $ANTHROPIC_API_KEY" \
    -H "anthropic-version: 2023-06-01" \
    -H "anthropic-beta: managed-agents-2026-04-01" \
    -H "content-type: application/json" \
    -d @- <<EOF
{
  "agent": "$AGENT_ID",
  "environment_id": "$ENVIRONMENT_ID",
  "title": "Quickstart session"
}
EOF
)

SESSION_ID=$(jq -er '.id' <<<"$session")

echo "Session ID: $SESSION_ID"

Send a message and stream the response

Open a stream, send a user event, then process events as they arrive:

# Send the user message first; the API buffers events until the stream attaches
curl -sS --fail-with-body \
  "https://api.anthropic.com/v1/sessions/$SESSION_ID/events" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: managed-agents-2026-04-01" \
  -H "content-type: application/json" \
  -d @- >/dev/null <<'EOF'
{
  "events": [
    {
      "type": "user.message",
      "content": [
        {
          "type": "text",
          "text": "Create a Python script that generates the first 20 Fibonacci numbers and saves them to fibonacci.txt"
        }
      ]
    }
  ]
}
EOF

# Open the SSE stream and process events as they arrive
while IFS= read -r line; do
  [[ $line == data:* ]] || continue
  json=${line#data: }
  case $(jq -r '.type' <<<"$json") in
    agent.message)
      jq -j '.content[] | select(.type == "text") | .text' <<<"$json"
      ;;
    agent.tool_use)
      printf '\n[Using tool: %s]\n' "$(jq -r '.name' <<<"$json")"
      ;;
    session.status_idle)
      printf '\n\nAgent finished.\n'
      break
      ;;
  esac
done < <(
  curl -sS -N --fail-with-body \
    "https://api.anthropic.com/v1/sessions/$SESSION_ID/stream" \
    -H "x-api-key: $ANTHROPIC_API_KEY" \
    -H "anthropic-version: 2023-06-01" \
    -H "anthropic-beta: managed-agents-2026-04-01" \
    -H "Accept: text/event-stream"
)

The agent will write a Python script, execute it in the container, and verify the output file was created. Your output will look similar to this:

I'll create a Python script that generates the first 20 Fibonacci numbers and saves them to a file.
[Using tool: write]
[Using tool: bash]
The script ran successfully. Let me verify the output file.
[Using tool: bash]
fibonacci.txt contains the first 20 Fibonacci numbers (0 through 4181).

Agent finished.

Get started with Claude Managed Agents

Core concepts

Prerequisites

Install the CLI

Install the SDK

Create your first session

What's happening

Next steps

Get started with Claude Managed Agents

Core concepts

Prerequisites

Install the CLI

Install the SDK

Create your first session

What's happening

Next steps