Connect-Apps: Composio’s Uniform Layer for Claude Tool Calls

Last post in this series, and it closes on connect-apps, a Claude Code plugin from Composio that solves a narrower version of the problem Zero (last week’s post) takes on at scale: getting Claude working access to specific services you already have accounts with, rather than a long tail of one-off tools.

A uniform layer over messy APIs

The pitch behind Composio’s approach is that every service’s API looks different – different auth flows, different request shapes, different error formats – and that heterogeneity is exactly what makes wiring up integrations tedious. Connect-apps abstracts that into one uniform execution layer: Claude emits a structured tool call, Composio validates it, authenticates against the right service, executes it, and hands back a machine-readable result.

In practice that means the first time you use Gmail, Slack, GitHub, or another supported service, Claude gives you an OAuth link, you complete the flow once, and the connection is live from then on.

Two ways to install it

For a one-off session:

claude --plugin-dir /path/to/connect-apps-plugin

For a persistent install so it’s available every time:

mkdir -p ~/.claude/skills/connect-apps
cp -R connect-apps-plugin/. ~/.claude/skills/connect-apps/
claude

Then run /connect-apps:setup. Note that this stores the API key in ~/.mcp.json, which is worth locking down if the machine is shared. The standalone connect/SKILL.md alone won’t fully configure the MCP connection – for working app actions you want the full connect-apps-plugin.

Wrapping up the series

That’s ten skills and plugins alongside the original humanizer post: a mix of writing tools, a full development methodology, a correction-and-learning loop, a security scanner, memory for code and memory for the agent itself, and two different takes on external tool access. If any of them turn out to be genuinely useful in daily use, I’ll likely follow up with a proper review once I’ve lived with them for a while.