OpenAI Agents SDK Social Media: Posta MCP + Function Tools

Why Posta + OpenAI Agents SDK?

Path 1 — Posta MCP via MCPServerStdio (recommended)

The Agents SDK loads MCP servers natively. Point it at the Posta server and the agent introspects every tool it needs.

pip install openai-agents

# agent.py
import os, asyncio
from agents import Agent, Runner
from agents.mcp import MCPServerStdio

async def main():
    async with MCPServerStdio(
        params={
            "command": "npx",
            "args": ["-y", "posta-mcp"],
            "env": {"POSTA_API_TOKEN": os.environ["POSTA_API_TOKEN"]},
        }
    ) as posta_mcp:
        agent = Agent(
            name="Social Publisher",
            instructions="Draft and schedule social posts. Match each platform's voice.",
            mcp_servers=[posta_mcp],
        )
        result = await Runner.run(agent, input=(
            "Draft a LinkedIn post and a Bluesky post about our v2 launch "
            "and schedule both for tomorrow 9am CET."
        ))
        print(result.final_output)

asyncio.run(main())

Path 2 — Wrap the REST API with @function_tool

Useful when you want a single typed call exposed to the agent — no MCP transport, no tool discovery.

import os, requests
from agents import Agent, Runner, function_tool

POSTA = "https://api.getposta.app"
HEADERS = {"Authorization": f"Bearer {os.environ['POSTA_API_TOKEN']}"}

@function_tool
def schedule_post(
    caption: str,
    social_account_ids: list[int],
    scheduled_at: str,
    media_ids: list[str] | None = None,
) -> str:
    """Create a Posta draft on the given accounts and schedule it.
    scheduled_at is ISO 8601. media_ids are Posta media IDs."""
    # Step 1 — create the draft
    r = requests.post(
        f"{POSTA}/v1/posts", headers=HEADERS, timeout=30,
        json={
            "caption": caption,
            "socialAccountIds": social_account_ids,
            **({"mediaIds": media_ids} if media_ids else {}),
        },
    )
    r.raise_for_status()
    post_id = r.json()["id"]
    # Step 2 — schedule it
    r = requests.post(
        f"{POSTA}/v1/posts/{post_id}/schedule", headers=HEADERS, timeout=30,
        json={"scheduledAt": scheduled_at},
    )
    r.raise_for_status()
    return f"Scheduled post {post_id} for {scheduled_at}"

agent = Agent(
    name="Social Publisher",
    instructions="Schedule social posts.",
    tools=[schedule_post],
)

Common patterns