Build an Agent Plugin - Entire
Build an agent plugin
Build an agent plugin when you want Entire to support a coding agent that is not built in yet. The external-agents repository includes an agent skill that researches the target agent, scaffolds the binary, writes tests, and implements the protocol. The protocol is language-agnostic; this guide uses that Go-based repo and its skill. For the protocol itself, see Architecture, Commands, Lifecycle, and Data Model.
Building a private or internal plugin? This guide is the upstream-contribution path (it ends in a pull request to external-agents). For a plugin you won’t contribute back, skip the issue and PR steps and follow the protocol reference above.
Before you start
Open an issue in entireio/external-agents before writing code. Adding support for a new agent creates a long-term support commitment, so align with maintainers first. You need:
- The target agent CLI installed and authenticated
- The Entire CLI installed
- Go and mise
- A target agent with lifecycle hooks or another reliable event mechanism
- Readable session or transcript data
- A stable session ID
Clone the repo
git clone https://github.com/entireio/external-agents.git
cd external-agents
mise trust
mise install
New integrations live under agents/entire-agent-<slug>. Each integration is a standalone binary named entire-agent-<slug>.
Run the Agent Skill
The repo includes an agent skill named entire-external-agent, and supported tools auto-discover it with no additional configuration. See the repo instructions for the current supported tools. Run the skill:
/entire-external-agent
When prompted, provide the target agent name and slug.
What the Skill Does
The skill runs three phases:
| Phase | What happens |
|---|---|
| Research | Finds the target agent’s hooks, session IDs, transcript storage, CLI commands, and capabilities. |
| Scaffold | Creates the plugin structure, protocol stubs, and lifecycle test wiring. |
| Implement | Uses compliance and lifecycle failures to implement the plugin and add tests. |
You can also run a single phase when you need to restart or inspect part of the process.
/entire-external-agent research
/entire-external-agent write-tests
/entire-external-agent implement
Reference examples
The external-agents repository contains working plugins you can inspect while building your own:
| Plugin | Target agent | Notes |
|---|---|---|
entire-agent-amp |
Amp | Project plugin with transcript preparation, token calculation, and compact transcript support. |
entire-agent-goose |
Goose | Project plugin that exports Goose sessions from SQLite-backed storage. |
entire-agent-kiro |
Kiro | Lifecycle hooks and transcript analysis for Kiro sessions. |
For a minimal reference implementation outside the main examples repo, see roger-roger.
Review the output
When the skill finishes, review:
agents/entire-agent-<slug>/AGENT.mdagents/entire-agent-<slug>/README.md- The declared capabilities
- Protocol compliance results
- Lifecycle test results
- Any remaining gaps or local dependencies
Treat captured hook payloads and transcript fixtures as ground truth. Documentation can drift.
Verify locally
Build the binary, put it on your PATH, and enable it in a test repository:
cd agents/entire-agent-<slug>
mise run build
export PATH="$PWD:$PATH"
cd /path/to/test-repo
entire enable --agent SLUG
Run the target agent and make a small file change. Then check that Entire captured the session:
entire status
entire checkpoint list
entire checkpoint explain CHECKPOINT_ID --short
Look for a checkpoint with the expected session, transcript, and modified files.
Open the PR
Reference the approved issue and include:
- Agent name and binary name
- Declared capabilities
- Protocol compliance status
- Lifecycle test status
- Unit test coverage
- Any local dependencies you could not test
- Known limitations
CI will build the agent and run the shared checks.