Installation and Quick Start

What You'll Learn

• ✅ Complete DCP plugin installation in 5 minutes
• ✅ Configure the plugin and verify successful installation
• ✅ See your first automatic pruning in action

Your Current Challenge

After using OpenCode for a while, your conversations get longer:

• AI reads the same file multiple times
• Tool error messages clutter your context
• Each conversation consumes a large number of tokens
• Longer conversations = slower AI responses

You want to automatically clean up redundant content in conversations without manual intervention.

Core Concept

DCP (Dynamic Context Pruning) is an OpenCode plugin that automatically removes redundant tool calls from conversation history, reducing token consumption.

How it works:

1. Automatic Detection: Analyzes conversation history before each message is sent
2. Intelligent Cleanup: Removes duplicate tool calls, stale errors, and overwritten writes
3. AI-Driven: AI can actively call discard and extract tools to optimize context
4. Transparent and Controllable: View pruning statistics via /dcp command, manually trigger cleanup

Key Advantages

• Zero Cost: Automatic strategies require no LLM calls
• Zero Configuration: Works out of the box with optimized defaults
• Zero Risk: Only modifies context sent to LLM, conversation history remains unchanged

🎒 Prerequisites

Before starting, ensure:

• [ ] OpenCode is installed (with plugin support)
• [ ] You know how to edit OpenCode configuration file
• [ ] You understand basic JSONC syntax (JSON with comments)

Important Note

DCP modifies the context content sent to the LLM but does not affect your conversation history. You can disable the plugin in your configuration at any time.

Follow Along

Step 1: Edit OpenCode Configuration File

Why You need to declare the DCP plugin in your OpenCode configuration so OpenCode automatically loads it on startup.

Open your OpenCode configuration file opencode.jsonc and add DCP to the plugin field:

// opencode.jsonc
{
    "plugin": ["@tarquinen/opencode-dcp@latest"],
}

You should see: The configuration file may have other plugins (if any), just add DCP at the end of the array.

Tip

Using the @latest tag ensures OpenCode automatically checks and fetches the latest version on startup.

Step 2: Restart OpenCode

Why Plugin configuration changes require a restart to take effect.

Completely close OpenCode, then restart it.

You should see: OpenCode starts normally without any error messages.

Step 3: Verify Plugin Installation

Why Confirm that the DCP plugin is loaded correctly and view the default configuration.

In an OpenCode conversation, enter:

/dcp

You should see: DCP command help information, indicating the plugin was installed successfully.

╭───────────────────────────────────────────────────────────╮
│                      DCP Commands                         │
╰───────────────────────────────────────────────────────────╯

  /dcp context      Show token usage breakdown for current session
  /dcp stats        Show DCP pruning statistics
  /dcp sweep [n]    Prune tools since last user message, or last n tools

Step 4: Check Default Configuration

Why Understand DCP's default configuration and confirm the plugin works as expected.

DCP automatically creates a configuration file on first run:

# View global configuration file
cat ~/.config/opencode/dcp.jsonc

You should see: Configuration file created with only the $schema field initially:

{
    "$schema": "https://raw.githubusercontent.com/Opencode-DCP/opencode-dynamic-context-pruning/master/dcp.schema.json"
}

The configuration file initially contains only the $schema field. All other configuration items use code defaults, requiring no manual configuration.

Default Configuration Explained

DCP's code defaults (no need to write to config file):

• deduplication: Automatic deduplication, removes duplicate tool calls
• purgeErrors: Automatically cleans error tool inputs from 4 turns ago
• discard/extract: AI-callable pruning tools
• pruneNotification: Displays detailed pruning notifications

If you need custom configuration, you can manually add these fields. See Configuration Guide for details.

Step 5: Experience Automatic Pruning

Why Use DCP in practice and see automatic pruning results.

Have a conversation in OpenCode where the AI reads the same file multiple times or executes tool calls that will fail.

You should see:

1. DCP automatically analyzes conversation history before each message is sent
2. If there are duplicate tool calls, DCP automatically cleans them up
3. After AI responds, you may see pruning notifications (depending on pruneNotification configuration)

Example pruning notification:

▣ DCP | ~12.5K tokens saved total

▣ Pruning (~12.5K tokens)
→ read: src/config.ts
→ write: package.json

Enter /dcp context to view current session token usage:

Session Context Breakdown:
──────────────────────────────────────────────────────────

System         15.2% │████████████████▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒│  25.1K tokens
User            5.1% │████▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒│   8.4K tokens
Assistant       35.8% │██████████████████████████████████████▒▒▒▒▒▒▒│  59.2K tokens
Tools (45)      43.9% │████████████████████████████████████████████████│  72.6K tokens

──────────────────────────────────────────────────────────

Summary:
  Pruned:          12 tools (~15.2K tokens)
  Current context: ~165.3K tokens
  Without DCP:     ~180.5K tokens

Checkpoint ✅

After completing these steps, you should:

• [ ] Added DCP plugin to opencode.jsonc
• [ ] OpenCode restarts and runs normally
• [ ] /dcp command displays help information
• [ ] Configuration file ~/.config/opencode/dcp.jsonc is created
• [ ] Can see pruning notifications in conversations or view pruning statistics via /dcp context

If a step fails:

• Check if opencode.jsonc syntax is correct (JSONC format)
• Check OpenCode logs for plugin loading errors
• Confirm OpenCode version supports plugin functionality

Common Pitfalls

Issue 1: Plugin Not Working

Symptom: Configuration added but no pruning effects visible

Cause: OpenCode not restarted or incorrect config file path

Solution:

1. Completely close OpenCode and restart
2. Check if opencode.jsonc location is correct
3. Check logs: log files in ~/.config/opencode/logs/dcp/daily/ directory

Issue 2: Configuration File Not Created

Symptom: ~/.config/opencode/dcp.jsonc does not exist

Cause: OpenCode hasn't called DCP plugin or config directory permission issues

Solution:

1. Confirm OpenCode has been restarted
2. Manually create config directory: mkdir -p ~/.config/opencode
3. Check plugin name in opencode.jsonc: @tarquinen/opencode-dcp@latest

Issue 3: Pruning Notifications Not Displayed

Symptom: No pruning notifications visible, but /dcp stats shows pruning occurred

Cause: pruneNotification configured as "off" or "minimal"

Solution: Modify configuration file:

"pruneNotification": "detailed"  // or "minimal"

Summary

Installing the DCP plugin is very simple:

1. Add plugin to opencode.jsonc
2. Restart OpenCode
3. Use /dcp command to verify installation
4. Default configuration works without additional adjustments

DCP's default enabled features:

• ✅ Automatic deduplication strategy (removes duplicate tool calls)
• ✅ Error cleanup strategy (cleans stale error inputs)
• ✅ AI-driven tools (discard and extract)
• ✅ Detailed pruning notifications

Next Step: Learn how to customize configuration to adjust pruning strategies for different scenarios.

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Coming Up Next

In the next lesson, we'll learn Configuration Guide

You'll learn:

• Multi-level configuration system (global, environment variables, project-level)
• All configuration options and recommended settings
• Turn protection, protected tools, and protected file patterns
• How to enable/disable different pruning strategies

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Appendix: Source Code Reference

Click to expand source code locations

Last updated: 2026-01-23

Feature	File Path	Line Range
Plugin Entry	index.ts	12-102
Config Manager	lib/config.ts	669-794
Command Handler	lib/commands/help.ts	1-40
Token Calculator	lib/commands/context.ts	68-174

Key Constants:

• MAX_TOOL_CACHE_SIZE = 1000: Maximum number of tool cache entries

Key Functions:

• Plugin(): Plugin registration and hook setup
• getConfig(): Load and merge multi-level configuration
• handleContextCommand(): Analyze current session token usage