How to Debug Unavailable Channels in Agent-Reach Doctor Output

To debug unavailable channels in the Agent-Reach doctor output, inspect the specific channel's check() method implementation, verify the backend binary exists and executes correctly using the probe module, and ensure required credentials are configured in config.yaml or environment variables.

The python -m agent_reach.cli doctor command generates a comprehensive health report for every channel configured in Agent-Reach, marking unavailable channels with a red X when their check() method returns a non-ok status or raises an exception. Understanding how the Doctor aggregates these results from agent_reach/doctor.py and the underlying channel implementations allows you to systematically diagnose and resolve backend connectivity issues.

How the Doctor Command Evaluates Channels

The Doctor orchestrates health checks through four distinct phases defined in agent_reach/doctor.py:

1. Channel Discovery: Lines 12-20 call get_all_channels() to retrieve every concrete subclass of BaseChannel from the registry.

2. Safe Execution: Lines 21-27 wrap each channel's check() call in a try/except block. If a channel raises an exception, the Doctor captures it and stores status="error" alongside the exception message.

3. Result Aggregation: Lines 28-34 construct a result dictionary containing status, message, tier, backends, and the runtime-selected active_backend.

4. Report Rendering: Lines 47-99 in format_report() group channels by tier and apply Rich styling. A red X appears for any channel where status is "off" or "error".

Why Channels Appear as Unavailable

Channels display as unavailable when their check() implementation detects environmental or configuration issues:

Missing External Tools

When a required binary (like yt-dlp for YouTube or twurl for Twitter) is not installed, the channel's check() method returns status="off" with a message indicating "未安装" (not installed). This check typically uses shutil.which() combined with a lightweight probe via agent_reach/probe.py.

Misconfigured Credentials

If required API keys, cookies, or login tokens are absent, check() returns "warn" (yellow !) with messages like "需配置/登录" (needs configuration/login). These credentials are retrieved via Config.get_secret() from agent_reach/config.py.

Probe Failures

Channels that rely on external backends call agent_reach.probe.probe_command to verify executability. If the probe fails, the Doctor records status="error" with the exception message, such as "体检异常：".

Stale Active Backend

When a check fails, lines 24-26 of doctor.py clear the active_backend field to prevent caching invalid backends. This ensures that previously successful checks don't leak stale data into error reports.

Configuration File Permissions

While not affecting channel status directly, lines 15-24 of doctor.py add security warnings (red lines) if ~/.agent-reach/config.yaml has overly permissive file permissions.

Step-by-Step Debugging Workflow

Follow this systematic approach to resolve unavailable channels:

1. Enable Verbose Output

Run the Doctor with the --verbose flag to see raw result dictionaries before formatting:

python -m agent_reach.cli doctor --verbose

This exposes the exact status and message values for each channel.

2. Inspect the Channel's Check Implementation

Open the specific channel file indicated by the error. For example, examine agent_reach/channels/youtube.py for YouTube issues. Look for the check() method signature:

def check(self, config):
    # Probes yt-dlp binary, verifies execution, sets active_backend

3. Verify Backend Binary Availability

Confirm the binary exists and is executable:

which yt-dlp
yt-dlp --version

Channels use both shutil.which() and probe_command to validate that binaries can actually execute, not just exist in PATH.

4. Run the Probe Manually

Test the backend directly using the probe module:

python -m agent_reach.probe yt-dlp --version

If this fails, the error message matches what the Doctor reports.

5. Check Backend Overrides

Verify you haven't set an invalid backend override via environment variables. Each channel respects a <CHANNEL>_BACKEND override based on ordered_backends in agent_reach/channels/base.py (lines 45-60):

echo $YOUTUBE_BACKEND  # Should be empty or a valid backend name

6. Validate Credentials

Ensure required secrets exist in ~/.agent-reach/config.yaml or as environment variables. The check() method calls Config.get_secret() to retrieve these values.

7. Re-run the Doctor

After fixing the underlying issue, execute the Doctor again to confirm the channel displays a green ✅.

Practical Code Examples

Reproducing a Failing Probe

Test backend availability programmatically:

from agent_reach.probe import probe_command

# The YouTube channel declares yt-dlp as its primary backend

result = probe_command(["yt-dlp", "--version"])
print(result)  # => ('error', 'yt-dlp: command not found')

Overriding Backend Selection

Force a specific backend for debugging:

import os
os.environ["REDDIT_BACKEND"] = "praw"  # Forces 'praw' to the front

from agent_reach.doctor import check_all
from agent_reach.config import Config

report = check_all(Config())
print(report["reddit"])

# => {'status': 'ok', 'active_backend': 'praw', ...}

Quick CLI Health Check

Programmatically run the Doctor from Python:

python - <<'PY'
from agent_reach.doctor import check_all, format_report
from agent_reach.config import Config
print(format_report(check_all(Config())))
PY

Key Source Files Reference

• agent_reach/doctor.py (lines 12-99): Orchestrates channel checks and formats the Rich report.
• agent_reach/channels/base.py (lines 45-60): Defines the Channel abstract class, ordered_backends, and default check().
• agent_reach/probe.py: Executes lightweight commands to confirm backend health.
• agent_reach/config.py: Handles YAML/ENV configuration and secret storage via get_secret().
• agent_reach/channels/<platform>.py: Platform-specific check() implementations (e.g., youtube.py, twitter.py).
• agent_reach/cli.py: Exposes the doctor sub-command and implements the --verbose flag.

Summary

• The Doctor never crashes; it captures all exceptions in agent_reach/doctor.py and reports them as status strings.
• Red X marks indicate status="off" (missing dependencies) or "error" (exceptions) returned by a channel's check() method.
• Debug systematically by enabling verbose output, inspecting the specific channel's implementation, and manually running probe_command.
• Verify environment by checking binary availability, backend overrides in ordered_backends, and credentials in config.yaml.

Frequently Asked Questions

What does the red X mean in the Agent-Reach Doctor output?

The red X indicates a channel is unavailable because its check() method returned a status of "off" (missing dependencies) or "error" (exception raised during check). This appears in the formatted report generated by format_report() in agent_reach/doctor.py when the status tuple contains these values instead of "ok".

How do I see the exact error message for a failing channel?

Run the Doctor with the --verbose flag implemented in agent_reach/cli.py. This prints the raw result dictionary containing the specific message field before Rich table formatting, revealing the exact exception text, missing binary notification, or configuration warning emitted by the channel's check() implementation.

Why does a channel show as unavailable when the binary is in my PATH?

The Doctor uses probe_command from agent_reach/probe.py to verify the binary can actually execute, not merely exist. Stale virtual environment shims or permission issues may cause which to locate a file that cannot run. Delete the invalid shim or reinstall the tool to ensure the binary exits cleanly when invoked.

Can I force the Doctor to use a specific backend for testing?

Yes. Set the <CHANNEL>_BACKEND environment variable (e.g., YOUTUBE_BACKEND=yt-dlp) to override the ordered_backends list defined in agent_reach/channels/base.py. This forces that backend to the front of the evaluation queue, useful for testing specific implementations without modifying configuration files.

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