# How to Debug Why a Specific Channel Isn't Working in Agent Reach > Debug Agent Reach channel failures effectively. Use the doctor CLI and inspect channel check methods to identify and resolve issues with backends binaries runtimes or authentication. - Repository: [Pnant/Agent-Reach](https://github.com/Panniantong/Agent-Reach) - Tags: how-to-guide - Published: 2026-07-11 --- **Use the built-in `doctor` CLI to identify whether the failure stems from missing backends, broken binaries, missing runtimes, or authentication issues, then inspect the specific channel's `check()` method in `agent_reach/channels/.py` to resolve the root cause.** Agent Reach abstracts every internet platform into a *channel* that inherits from the abstract `Channel` base class. When a specific channel stops working, the bug usually hides in one of three areas: backend availability, runtime configuration, or user configuration overrides. The `probe_command` logic in [`agent_reach/probe.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/probe.py) and the per-channel `check()` methods provide a systematic path to debug why a specific channel isn't working in Agent Reach. ## Run the Built-In Diagnostics Doctor Start by running the health check aggregator to see the current status of all channels: ```bash python -m agent_reach.cli doctor ``` The `doctor` command (implemented in [`agent_reach/doctor.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/doctor.py)) iterates over every registered channel and calls its `check()` method. It prints a status table that categorizes each channel as `ok`, `warn`, `error`, or `off`. Identify the failing channel in this output and note the diagnostic message provided. ## Locate the Channel Implementation Each concrete channel lives in its own file under `agent_reach/channels/`. For example: - [`agent_reach/channels/twitter.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/channels/twitter.py) - [`agent_reach/channels/youtube.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/channels/youtube.py) Open the file for your failing channel and examine the `check()` method. This method defines the specific backends the channel tries and the conditions that produce each status. The source code reveals exactly which command-line tools and environment variables are required. ## Verify Backend Availability The core probing logic resides in [`agent_reach/probe.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/probe.py). The `probe_command` function executes a lightweight health check (usually `--version` or a status subcommand) and classifies the result into four states: - **`missing`** – The command is not on your `PATH` - **`broken`** – The command exists but cannot execute (common with stale virtual-environment shims) - **`timeout` / `error`** – The command runs but exits with an error or hangs - **`ok`** – The command is healthy and responsive Confirm the backend binary is accessible: ```bash which ``` If the command is missing, install it according to the hint in the doctor output (often `uv tool install` or `pipx reinstall`). If the command exists but is broken, reinstall the package to refresh the shim. ## Check Runtime Configuration and Credentials Beyond the binary itself, channels often require specific runtimes or authentication tokens. The `check()` method in each channel file validates these dependencies. **YouTube:** Requires a JavaScript runtime. The channel checks `shutil.which("deno")` and `shutil.which("node")`. If neither is found, install Node.js or Deno: ```bash # Install Node.js via nvm curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash nvm install --lts ``` **Twitter:** Requires authentication tokens. Verify these environment variables are set: ```bash echo $TWITTER_AUTH_TOKEN echo $TWITTER_CT0 ``` If these are unset, export them as shown in the doctor's hint, or ensure you have a valid browser login for OpenCLI. ## Inspect Config Overrides The `Channel` base class in [`agent_reach/channels/base.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/channels/base.py) implements `ordered_backends()`, which respects user overrides. If you have set a `_backend` key in [`config.yaml`](https://github.com/Panniantong/Agent-Reach/blob/main/config.yaml) or the corresponding environment variable, that backend is forced to the front of the candidate list, potentially hiding a functional fallback. Check your configuration for stale overrides: ```bash # Check environment echo $TWITTER_BACKEND # Check config.yaml cat ~/.config/agent_reach/config.yaml | grep backend ``` Remove or correct the override and re-run the doctor. ## Manually Test the Backend To bypass Agent Reach's abstraction and test the backend directly, execute the same command that `probe_command` uses: ```bash yt-dlp --version # YouTube backend twitter status # Twitter CLI backend bird check # Bird CLI backend ``` Any error output from these commands provides additional clues beyond the generic status messages. ## Summary - **Run the doctor:** Use `python -m agent_reach.cli doctor` to identify which channel is failing and why. - **Check the source:** Inspect the channel's `check()` method in `agent_reach/channels/.py` to see required backends and credentials. - **Verify binaries:** Use `which` and manual execution to confirm backend commands are on your `PATH` and not broken. - **Validate runtimes:** Ensure required runtimes (Node.js, Deno) and authentication tokens are installed and exported. - **Audit overrides:** Remove or correct `_backend` overrides in [`config.yaml`](https://github.com/Panniantong/Agent-Reach/blob/main/config.yaml) or environment variables that might be forcing a non-functional backend. ## Frequently Asked Questions ### Why does the doctor show "warn" instead of "error" for my channel? A `warn` status means the backend binary is installed and executable, but the channel's `check()` method detected a non-critical issue, such as missing authentication credentials or an optional runtime dependency. The channel may still function partially, but you should follow the hint in the doctor output to resolve the warning and restore full functionality. ### How do I find which backends a specific channel supports? Open the channel's implementation file in `agent_reach/channels/.py` (for example, [`twitter.py`](https://github.com/Panniantong/Agent-Reach/blob/main/twitter.py) or [`youtube.py`](https://github.com/Panniantong/Agent-Reach/blob/main/youtube.py)). The `check()` method or the class attribute `backends` lists the command-line tools the channel attempts to use. The `ordered_backends()` method in [`agent_reach/channels/base.py`](https://github.com/Panniantong/Agent-Reach/blob/main/agent_reach/channels/base.py) determines the precedence order, including any user overrides. ### Can I force Agent Reach to use a specific backend if the default fails? Yes. Set the `_backend` configuration option in your [`config.yaml`](https://github.com/Panniantong/Agent-Reach/blob/main/config.yaml) or export it as an uppercase environment variable (e.g., `TWITTER_BACKEND=twitter-cli`). This forces `ordered_backends()` to prioritize that specific backend. However, ensure the forced backend is actually installed and functional, or you will mask working fallbacks. ### What if the doctor reports "ok" but the channel still fails during actual use? The `check()` method performs lightweight health probes (often just `--version` checks) that verify binary presence and basic execution, but they do not exhaustively test all API endpoints or authentication workflows. If the doctor shows `ok` but operations fail, manually run the backend command with a real operation (e.g., `twitter status` or `yt-dlp `) to see the actual error output, and verify that any required environment variables contain valid, non-expired tokens.