Fix clw-prompt-exhausted: Resolve Prompt Token Limit Exhaustion

The clw-prompt-exhausted error occurs in OpenClaw when the maximum allowed prompt tokens have been consumed during a single operation or within a billing period. This resource exhaustion typically manifests when processing large files, running complex multi-step tasks, or attempting to execute commands that exceed configured token budgets. Understanding the underlying mechanics of prompt consumption and implementing proper management strategies is essential for maintaining productive workflows in OpenClaw environments.

1. Symptoms

When the clw-prompt-exhausted error triggers, users encounter several distinct indicators that signal token budget depletion. The primary symptom manifests as a non-zero exit code returned by the OpenClaw CLI, specifically indicating that the prompt processor encountered a state where additional token allocation was impossible. Shell output typically displays the error message alongside diagnostic information showing the current token count versus the configured maximum.

Typical error output:

[ERROR] clw-prompt-exhausted: Prompt token budget exceeded
Current usage: 8192 tokens
Configured limit: 8192 tokens
Consider splitting your task or adjusting token budget settings.

Additional symptoms include incomplete command execution where partial results may be visible before the error terminates processing. Users frequently report that interactive sessions terminate abruptly without saving intermediate state, leading to lost work. In automated pipelines, this error causes downstream tasks to fail silently or produce malformed output, making debugging particularly challenging in CI/CD environments. The error may also appear alongside rate limiting messages if both resource constraints are hit simultaneously, creating confusion about which limit triggered the failure.

2. Root Cause

The clw-prompt-exhausted error stems from fundamental constraints in the token-based resource management model that OpenClaw implements for API calls and processing operations. When users request operations that collectively consume tokens beyond configured or default thresholds, the system must halt execution to prevent uncontrolled resource consumption. This mechanism exists to protect both the user’s budget and the underlying infrastructure from runaway processes.

Several specific scenarios commonly trigger this exhaustion. Processing files with extensive context requirements—such as large codebases, lengthy documentation, or multi-file project analyses—rapidly depletes token budgets because each token represents computational cost. Users who modify prompts to include excessive system-level instructions, detailed examples, or verbose context augmentation inadvertently consume available tokens before the actual task begins. The accumulation effect is particularly pronounced in iterative workflows where each run adds historical context to maintain conversation continuity, eventually exceeding available headroom.

Configuration missteps also contribute significantly to prompt exhaustion. Projects configured with artificially low token budgets for their operational requirements will encounter this error routinely. Conversely, some users encounter exhaustion when their configured budget exceeds reasonable expectations for their usage patterns, leading to unexpectedly high consumption during normal operations. The OpenClaw CLI maintains internal buffers for context management, and when these buffers fill before reaching natural completion points, the prompt processor must terminate with the exhaustion error.

3. Step-by-Step Fix

Resolving the clw-prompt-exhausted error requires a systematic approach addressing both immediate symptom relief and long-term prevention. Follow these steps to restore functionality and optimize your OpenClaw configuration.

Step 1: Examine Current Configuration

First, inspect your current OpenClaw configuration to understand existing token limits and consumption patterns.

clw config show
clw status --verbose

Step 2: Adjust Token Budget (if needed)

Increase the token budget if your workload genuinely requires more resources. Edit your OpenClaw configuration file:

clw config set --key prompt.max_tokens --value 16384

Before:

{
  "prompt": {
    "max_tokens": 8192
  }
}

After:

{
  "prompt": {
    "max_tokens": 16384
  }
}

Step 3: Optimize Prompt Structure

Reduce token consumption by trimming unnecessary context and optimizing prompt templates.

Before:

System: You are an expert programmer. You must follow best practices.
Context: The following code was written by a senior developer.
Previous attempts: Multiple approaches were tried.
Additional notes: This is part of a larger system.

After:

System: Expert programmer following best practices.
Context: Code from senior developer, part of larger system.

Step 4: Enable Automatic Chunking

Configure OpenClaw to automatically split large operations into manageable segments:

clw config set --key prompt.auto_chunk --value true
clw config set --key prompt.chunk_size --value 4096

Step 5: Implement Session Management

Clear accumulated context periodically to prevent gradual token accumulation:

clw session reset
clw session clear --history

4. Verification

After implementing fixes, verify that the clw-prompt-exhausted error no longer occurs by running operational tests that previously triggered the issue. Execute the command that previously failed and confirm successful completion:

clw process --input large-file.txt
echo $?  # Should return 0 for success

Monitor token consumption during execution with verbose output:

clw process --input large-file.txt --verbose 2>&1 | grep -i token

Verify configuration changes took effect:

clw config show | grep -A2 prompt

The configuration should reflect your updated values, and the token counter should show consumption staying below configured limits during normal operations. For automated workflows, implement health checks that capture exit codes and trigger alerts if the error recurs, ensuring rapid response to persistent issues.

5. Common Pitfalls

Several common mistakes can either exacerbate prompt exhaustion issues or create new problems during troubleshooting. Avoiding these pitfalls ensures smoother resolution and prevents recurring errors.

Overcompensating with Token Limits: Setting token budgets excessively high can lead to runaway costs and delayed error detection. Start with conservative increases and monitor actual consumption patterns before adjusting further. A doubling of limits from 8192 to 16384 is reasonable; jumping to 100000 often indicates a misunderstanding of the underlying problem.

Neglecting Session Cleanup: Failing to reset sessions between major operations causes token accumulation that eventually triggers exhaustion. Establish regular session reset practices in long-running workflows, particularly when processing multiple files or running batch operations. Some users mistakenly believe closing the terminal clears session state, but OpenClaw maintains history across sessions until explicitly cleared.

Misunderstanding Auto-Save Behavior: OpenClaw may save partial results before exhausting prompts, creating inconsistent outputs. Always verify that completed work is in a valid state and reschedule incomplete operations rather than assuming saved checkpoints are complete. This is especially critical in production environments where partial file writes could corrupt data.

Ignoring Prompt Template Costs: System prompts, instructions, and examples consume tokens before your actual input is processed. Adding verbose frameworks or extensive examples to templates silently consumes budget, leaving less room for actual work. Profile your templates to understand baseline token costs before adding new instructions.

Similar resource-related errors frequently accompany or precede the clw-prompt-exhausted error, and understanding their relationships helps with comprehensive troubleshooting.

clw-rate-limit-exceeded: This error occurs when API call frequency exceeds configured thresholds, which often coincides with prompt exhaustion in high-volume workflows. While prompt exhaustion concerns token counts within operations, rate limiting tracks operation frequency, making both relevant for optimization.

clw-context-overflow: When processed content exceeds available context window capacity, this error triggers before token exhaustion in scenarios involving extremely large inputs. The distinction lies in immediate processing limits versus accumulated budget exhaustion.

clw-token-budget-exceeded: Functionally similar to clw-prompt-exhausted but potentially triggered at different checkpoints in the processing pipeline. Some workflows hit context overflow while others reach budget limits first, depending on configuration and operation types.

Addressing any of these related errors often resolves or prevents clw-prompt-exhausted through shared optimization strategies around prompt management, configuration tuning, and workflow restructuring.