How the Doctor Command Detects Working Backends in Agent‑Reach

The doctor command detects working backends by iterating over registered backend classes in agent_reach/backends/, invoking their check() methods with configuration from agent_reach/config.py, and aggregating health status from dependent channels to produce a diagnostic report.

The doctor command is the built‑in diagnostics tool of Agent‑Reach that validates environment configuration and backend connectivity before normal operations begin. When invoked, it systematically probes every supported backend adapter and its associated channels to verify that external platform integrations are functional.

Architecture of the Doctor Command

Entry Point and CLI Dispatch

The diagnostic process starts in agent_reach/cli.py, where the CLI parser dispatches the doctor sub‑command to the Doctor class. The Doctor.run() method defined in agent_reach/doctor.py serves as the orchestration engine that coordinates the entire health‑check workflow.

Backend Discovery and Registry

The Doctor class discovers available backends by iterating over the registry in agent_reach/backends/__init__.py. Each entry must be a subclass of BaseBackend, such as the default implementation found in agent_reach/backends/opencli.py. This registry pattern allows the diagnostic tool to automatically detect new backends without requiring modifications to the doctor's core logic.

Detection Mechanism Step-by-Step

Configuration Loading

Before executing health checks, the doctor retrieves backend‑specific settings via the class method config_key(). This method returns a configuration key that maps to values loaded from agent_reach/config.py, which aggregates YAML files and environment variables. Backends use these credentials and endpoint URLs to initialize their clients.

Health Check Execution

Each backend implements a check() method that performs a lightweight validation of connectivity and authentication. The Doctor wraps this call in a try/except block: if the method returns True, the backend is marked as working; if it raises an exception, the error is captured and the backend is marked as failed. For example, the OpenCliBackend in agent_reach/backends/opencli.py verifies that its target API endpoint returns a successful response.

Channel-Level Verification

After a backend passes its initial health check, the doctor proceeds to validate every channel that depends on that backend. Channels are defined in files under agent_reach/channels/ and inherit from BaseChannel. Each channel provides its own check() implementation, typically performing a minimal read operation or "ping" request to the target platform. Results are aggregated under the parent backend’s entry in the final report.

Reporting and Exit Codes

The doctor uses the rich library to render a colored table: green rows indicate successful backends and channels, red rows flag failures, and yellow rows denote optional components that lack configuration. The command exits with status 0 if all required backends are healthy; otherwise, it exits with a non‑zero code, enabling CI pipelines to fail fast.

Practical Examples

Running the Doctor Command

$ python -m agent_reach.cli doctor
╭───────────────────────────────────────╮
│   Agent‑Reach Diagnostics – Backend Status   │
╰───────────────────────────────────────╯
✅ OpenCLI backend – reachable (https://api.opencli.dev)
   ✅ Twitter channel – OK
   ✅ Reddit channel – OK
   ⚠️  YouTube channel – missing API key
❌ MCP server backend – connection refused
   ❌  MCP skill integration – unavailable

Programmatic Diagnostic Invocation

from agent_reach.doctor import Doctor

# Returns a dict of {backend_name: bool}

status = Doctor().run()
if not all(status.values()):
    raise RuntimeError("One or more backends are not functional")

Implementing a Custom Backend for Auto‑Detection

# In a new file: agent_reach/backends/myservice.py

from agent_reach.backends.base import BaseBackend

class MyServiceBackend(BaseBackend):
    @classmethod
    def config_key(cls) -> str:
        return "myservice"

    def check(self) -> bool:
        # Simple health‑check request

        resp = self.http.get(self.base_url + "/health")
        resp.raise_for_status()
        return resp.json().get("status") == "ok"

After adding the file and updating agent_reach/backends/__init__.py, the doctor command automatically probes MyServiceBackend on the next run.

Summary

• The doctor command is implemented in agent_reach/doctor.py and invoked via agent_reach/cli.py.
• It discovers backends through the registry in agent_reach/backends/__init__.py.
• Each backend must implement config_key() for configuration lookup and check() for health validation.
• Channel health checks in agent_reach/channels/ provide granular verification of platform connectivity.
• Results are displayed using rich tables, with exit codes indicating overall health status.

Frequently Asked Questions

What triggers a backend to fail the doctor check?

A backend fails if its check() method raises an exception, such as ConnectionError for unreachable endpoints, AuthenticationError for invalid credentials, or KeyError for missing configuration values in agent_reach/config.py.

Can I add a custom backend that the doctor command will automatically detect?

Yes. Create a new file in agent_reach/backends/, subclass BaseBackend, implement config_key() and check(), and import it in agent_reach/backends/__init__.py. The doctor command will automatically include it in the next diagnostic run.

How does the doctor command handle partial failures across channels?

The doctor aggregates results hierarchically. If a backend passes its check() but one of its channels fails, the backend is marked as degraded with specific channel errors listed. The overall exit code remains non‑zero if any required component fails.

Where is the exit status logic defined in the source code?

The exit status logic resides in agent_reach/doctor.py within the Doctor.run() method, which returns a boolean dictionary converted to a system exit code by the CLI dispatcher in agent_reach/cli.py.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}