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CLI Binary Not Found

Agent-Ctrl uses CliBinaryGuard to verify that the required CLI binary (claude, codex, opencode, pi, or gemini) is available before every execution. If the binary cannot be found, a RuntimeException is thrown immediately — before any prompt is sent to the agent. The error message identifies the missing binary and provides installation guidance: 
Claude Code CLI executable `claude` was not found in PATH. Install Claude Code CLI and ensure `claude` is available in PATH.
// @doctest id="0bc4"

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Resolution Steps

  1. Verify installation. Run the CLI binary directly in your terminal to confirm it is installed: 
    claude --version
codex --version
opencode --version
pi --version
gemini --version
  2. Complete authentication. Most agents require interactive authentication on first use. Run the CLI interactively at least once to complete any setup flows before using it through Agent-Ctrl.
  3. Check PATH visibility. The binary must be in the system PATH visible to your PHP process. This is not always the same as your shell’s PATH. If you installed the CLI in a non-standard location (e.g., via nvm or a custom prefix), ensure that location is included in the PATH used by your web server, supervisor, or CLI runner. You can verify the PATH available to PHP: 
    php -r "echo getenv('PATH');"
  4. Consider the sandbox driver. The binary preflight check behaves differently depending on the sandbox driver:
    • Host, Firejail, Bubblewrap — The binary must be available on the host system. The guard checks the host PATH.
    • Docker, Podman — The guard skips the preflight check entirely, because the binary is expected to be inside the container image.

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Working Directory Problems

When you call inDirectory(), the bridge validates that the directory exists before changing into it. If it does not exist, an InvalidArgumentException is thrown with the path: 
// This will throw if /nonexistent/path does not exist
$response = AgentCtrl::claudeCode()
    ->inDirectory('/nonexistent/path')
    ->execute('List files.');
// @doctest id="292b"

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Common Causes

  • Typos or relative paths. Always use absolute paths. Relative paths resolve against the PHP process’s current working directory, which may differ from what you expect.
  • Deleted or unmounted directories. The directory may have been removed or unmounted between the time you configured the builder and the time execution begins.
  • Permission issues. The PHP process may not have permission to access the directory. Check file permissions with ls -la and ensure the user running PHP has read (and possibly write) access.

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Concurrency Warning

inDirectory() changes the PHP process’s current working directory using chdir() for the duration of the execution and restores it afterward. If your PHP process serves multiple requests concurrently (e.g., with Swoole, RoadRunner, or a threaded server), working directory changes affect the entire process. In concurrent environments, ensure that each request either uses absolute paths exclusively or coordinates directory changes carefully.

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Non-Zero Exit Codes

Agent-Ctrl treats exit codes as data, not errors. A completed execution with a non-zero exit code does not throw an exception. It is your responsibility to check the result: 
$response = AgentCtrl::codex()->execute('Perform a complex refactoring.');

if (!$response->isSuccess()) {
    echo "Agent failed with exit code: {$response->exitCode}\n";
    echo "Partial output: " . $response->text() . "\n";
}
// @doctest id="85e9"

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Common Exit Codes

Exit CodeTypical Cause
0Successful completion
1General error — invalid configuration, agent-side failure, or unhandled exception within the agent
2Invalid arguments passed to the CLI binary
124Process killed due to timeout (SIGTERM)
137Process killed due to timeout (SIGKILL, after SIGTERM grace period)
The text output from a failed execution may still contain useful information — partial results, error messages from the agent, or diagnostic output. Always inspect text() even when isSuccess() returns false.

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Timeout Issues

The default timeout is 120 seconds. Complex tasks, large codebases, or agents that perform many tool calls may need significantly more time: 
$response = AgentCtrl::claudeCode()
    ->withTimeout(600) // 10 minutes
    ->execute('Perform a comprehensive codebase review.');
// @doctest id="c155"
When an execution times out:
  1. The sandbox executor sends a termination signal to the process.
  2. The response contains whatever output was produced before the timeout.
  3. The exit code will be non-zero (typically 124 or 137).
  4. isSuccess() will return false.

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Guideline for Timeout Values

Task TypeSuggested Timeout
Simple questions or summaries60-120 seconds
Code review of a single file120-300 seconds
Multi-file refactoring300-600 seconds
Full codebase analysis600-900 seconds
Complex multi-step tasks600+ seconds
Setting timeouts below 30 seconds is generally not recommended. Agents need time to start up, read context, plan, and execute tools before producing output.

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Streaming vs. Process Errors

There are two distinct categories of errors during execution, and they are handled differently.

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Stream Errors (Operational)

These are error events emitted by the agent during normal streaming. They represent issues the agent encountered while working — a tool failure, a rate limit, an API error, or a malformed request. They are delivered through the onError() callback: 
$response = AgentCtrl::openCode()
    ->onError(function (string $message, ?string $code): void {
        error_log("Stream error [{$code}]: {$message}");
    })
    ->executeStreaming('Process this task.');
// @doctest id="744e"
Stream errors do not prevent the execution from completing. The agent may recover and continue working after emitting an error event. The final AgentResponse is still returned normally.

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Process Errors (Fatal)

These are PHP exceptions thrown when something goes fundamentally wrong — the binary is missing, the working directory does not exist, the process cannot be started, or the sandbox executor encounters a fatal error. These exceptions propagate normally and must be caught with try/catch: 
try {
    $response = AgentCtrl::claudeCode()->execute('Do something.');
} catch (\RuntimeException $e) {
    // Binary not found, process failed to start, etc.
    echo "Process error: " . $e->getMessage();
} catch (\InvalidArgumentException $e) {
    // Working directory does not exist
    echo "Configuration error: " . $e->getMessage();
}
// @doctest id="bf98"
The key distinction: stream errors are data (delivered via callbacks), while process errors are exceptions (thrown and propagated through the call stack).

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Parse Failures

Agent-Ctrl parses each agent’s JSON Lines output to extract text, tool calls, session IDs, and metadata. If a line contains malformed JSON, the behavior depends on the parser’s fail-fast setting:

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Fail-Fast Mode (Default)

When fail-fast is enabled, a JsonParsingException is thrown immediately upon encountering malformed JSON. This is the default behavior and ensures that corrupt data does not silently corrupt your results: 
use Cognesy\Utils\Json\JsonParsingException;

try {
    $response = AgentCtrl::claudeCode()->execute('Do something.');
} catch (JsonParsingException $e) {
    echo "Malformed JSON in agent output: " . $e->getMessage();
}
// @doctest id="0768"

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Tolerant Mode

When fail-fast is disabled (configured at the bridge level), malformed lines are silently skipped and counted. After execution, you can inspect the parse diagnostics: 
if ($response->parseFailures() > 0) {
    echo "Skipped {$response->parseFailures()} malformed JSON lines.\n";
    foreach ($response->parseFailureSamples() as $sample) {
        echo "  Sample: {$sample}\n";
    }
}
// @doctest id="ba40"

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Common Causes of Parse Failures

  • CLI version mismatch. The agent’s CLI tool was updated and its output format changed. Update Agent-Ctrl to the latest version.
  • Debug output mixed into the stream. The agent’s CLI is emitting debug messages, warnings, or progress indicators alongside its JSON output. Check the CLI’s verbose/quiet settings.
  • Corrupted process output. The process was interrupted mid-line, producing incomplete JSON. This can happen during timeouts or system resource exhaustion.

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Debugging with the Console Logger

Agent-Ctrl includes a built-in AgentCtrlConsoleLogger that displays detailed, color-coded execution telemetry. This is invaluable for understanding the execution flow, diagnosing performance bottlenecks, and identifying where problems occur.

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Basic Usage

use Cognesy\AgentCtrl\AgentCtrl;
use Cognesy\AgentCtrl\Broadcasting\AgentCtrlConsoleLogger;

$logger = new AgentCtrlConsoleLogger();

$response = AgentCtrl::claudeCode()
    ->wiretap($logger->wiretap())
    ->execute('Analyze this codebase.');
// @doctest id="37b1"

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Configuration Options

The logger accepts several constructor parameters to control what is displayed: 
$logger = new AgentCtrlConsoleLogger(
    useColors: true,          // Color-coded output (auto-detects terminal support)
    showTimestamps: true,     // Show HH:MM:SS.mmm timestamps
    showAgentType: true,      // Show [claude-code] / [codex] / [opencode] prefix
    showToolArgs: true,       // Show tool input arguments
    showStreaming: true,      // Show stream processing events
    showSandbox: true,        // Show sandbox setup events
    showPipeline: true,       // Show request/response pipeline events
    maxArgLength: 100,        // Truncate tool arguments to this length
);
// @doctest id="edf6"

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Event Categories

The logger groups events into categories with color-coded labels:
LabelColorEvents
EXECCyanExecution started
DONEGreenExecution completed (with exit code, tool count, cost, tokens)
FAILRedError occurred
TOOLYellowTool used (with name and arguments)
TEXTGrayText received (with length)
PROCCyanProcess started / completed
SBOXBlueSandbox initialized / policy configured / ready
STRMGrayStream processing started / completed
REQTGrayRequest built
CMDGrayCommand spec created
RESPGrayResponse parsing started / data extracted / completed

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Example Output

14:23:01.456 [claude-code] [EXEC] Execution started [model=claude-sonnet-4-5, prompt=Analyze this codebase...]
14:23:01.458 [claude-code] [PROC] Process started [commands=12]
14:23:03.210 [claude-code] [TOOL] Read {path=/src/UserService.php}
14:23:04.890 [claude-code] [TOOL] Bash {command=php -l src/UserService.php}
14:23:06.123 [claude-code] [TEXT] Text received [length=1432]
14:23:06.125 [claude-code] [DONE] Execution completed [exit=0, tools=5, tokens=0]
// @doctest id="7544"

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Common Pitfalls

Using continueSession() with the wrong agent. Session IDs are agent-specific. Session IDs are agent-specific and incompatible across bridges. Always use the same agent type when continuing or resuming a session. Forgetting to check isSuccess(). A completed execution with a non-zero exit code does not throw an exception. Always verify the result before using the text output as authoritative. Setting very short timeouts. Agents need time to start up, read context, and execute tools. Timeouts under 30 seconds may cause premature termination for anything beyond trivial prompts. Relative paths in inDirectory(). Always use absolute paths. Relative paths resolve against the PHP process’s current working directory, which may differ from your expectations depending on how the process was started. Running in concurrent PHP environments. The inDirectory() method uses chdir(), which affects the entire PHP process. In Swoole, RoadRunner, or other concurrent PHP environments, this can cause race conditions between requests. Use absolute paths throughout and avoid inDirectory() if possible, or ensure proper isolation. Ignoring parse failures. If parseFailures() returns a non-zero value, some of the agent’s output was not processed. This may mean missing tool calls, incomplete text, or lost metadata. Investigate the parseFailureSamples() to determine the cause.