OpenCode-Tokenscope, Token Analyzer Plugin

Comprehensive token usage analysis and cost tracking for OpenCode AI sessions

Track and optimize your token usage across system prompts, user messages, tool outputs, and more. Get detailed breakdowns, accurate cost estimates, and visual insights for your AI development workflow.

Installation

Option 1: npm (Recommended)

Install globally:

npm install -g @ramtinj95/opencode-tokenscope

Add to your opencode.json (create one in your project root or ~/.config/opencode/opencode.json for global config):
```
{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["@ramtinj95/opencode-tokenscope"]
}
```
Create the /tokenscope command by creating ~/.config/opencode/command/tokenscope.md:

mkdir -p ~/.config/opencode/command
cat > ~/.config/opencode/command/tokenscope.md << 'EOF'
---
description: Analyze token usage across the current session with detailed breakdowns by category
---

Call the tokenscope tool directly without delegating to other agents.
Leave sessionID unset unless the user explicitly asked to analyze a different session.
Then cat the token-usage-output.txt. DONT DO ANYTHING ELSE WITH THE OUTPUT.
EOF

Restart OpenCode and run /tokenscope

To always get the latest version automatically, use @latest:

{
  "plugin": ["@ramtinj95/opencode-tokenscope@latest"]
}

Option 2: Install Script

curl -sSL https://raw.githubusercontent.com/ramtinJ95/opencode-tokenscope/main/plugin/install.sh | bash

Then restart OpenCode and run /tokenscope

Updating

If installed via npm:

Config in `opencode.json`	Behavior
`"@ramtinj95/opencode-tokenscope"`	Uses the version installed at install time. Never auto-updates.
`"@ramtinj95/opencode-tokenscope@latest"`	Fetches latest version every time OpenCode starts.
`"@ramtinj95/opencode-tokenscope@1.6.3"`	Pins to exact version 1.6.3. Never updates.

To manually update:

npm update -g @ramtinj95/opencode-tokenscope

Or use @latest in your opencode.json to auto-update on OpenCode restart.

If installed via script:

Option 1: Local script (if you have the plugin installed)

bash ~/.config/opencode/plugin/install.sh --update

Option 2: Remote script (always works)

curl -sSL https://raw.githubusercontent.com/ramtinJ95/opencode-tokenscope/main/plugin/install.sh | bash -s -- --update

The --update flag skips dependency installation for faster updates.

Usage

Simply type in OpenCode:

/tokenscope

The plugin will:

Analyze the current session
Count tokens across all categories
Analyze all subagent (Task tool) child sessions recursively
Calculate costs based on API telemetry
Save detailed report to token-usage-output.txt

Options

sessionID: Optional explicit session ID. Leave unset to analyze the current session; blank values are ignored
limitMessages: Limit entries shown per category (1-10, default: 3)
includeSubagents: Include subagent child session costs (default: true)

Reading the Full Report

cat token-usage-output.txt

Features

Comprehensive Token Analysis

5 Category Breakdown: System prompts, user messages, assistant responses, tool outputs, and reasoning traces
Visual Charts: Easy-to-read ASCII bar charts with percentages and token counts
Smart Inference: Automatically infers system prompts from API telemetry (since they're not exposed in session messages)

Context Breakdown Analysis

System Prompt Components: See token distribution across base prompt, tool definitions, environment context, project tree, and custom instructions
Automatic Estimation: Estimates breakdown from cache_write tokens when system prompt content isn't directly available
Tool Count: Shows how many tools are loaded and their combined token cost

Tool Definition Cost Estimates

Per-Tool Estimates: Lists all enabled tools with estimated schema token costs
Argument Analysis: Infers argument count and complexity from actual tool calls in the session
Complexity Detection: Distinguishes between simple arguments and complex ones (arrays/objects)

Cache Efficiency Metrics

Cache Hit Rate: Visual display of cache read vs fresh input token distribution
Cost Savings: Calculates actual savings from prompt caching
Effective Rate: Shows what you're actually paying per token vs standard rates

Accurate Cost Tracking

Models.dev Pricing Database: Pricing data synced from models.dev across thousands of provider/model entries
Cache-Aware Pricing: Properly handles cache read/write tokens with discounted rates
Per-Call Step Telemetry: Reads stored step-finish records so multi-step assistant turns and tool loops count every API call, not just the final step saved on the assistant message
Session-Wide Billing: Aggregates costs across all API calls in your session

Subagent Cost Tracking

Child Session Analysis: Recursively analyzes all subagent sessions spawned by the Task tool
Aggregated Totals: Shows combined tokens, costs, and API calls across main session and all subagents
Per-Agent Breakdown: Lists each subagent with its type, token usage, cost, and API call count
Optional Toggle: Enable/disable subagent analysis with the includeSubagents parameter

Advanced Features

Tool Usage Stats: Track which tools consume the most tokens and how many times each is called
API Call Tracking: See total API calls for main session and subagents
Top Contributors: Identify the biggest token consumers
Model Normalization: Handles provider/model format automatically
Multi-Tokenizer Support: Uses official tokenizers (tiktoken for OpenAI, lightweight Hugging Face tokenizers for others)
Configurable Sections: Enable/disable analysis features via tokenscope-config.json

Skill Analysis

Available Skills: Shows the always-available skill catalog token cost (including the verbose system-prompt catalog OpenCode injects on every API call)
Available Subagents: Shows all subagents listed in the Task tool definition with their token cost
Loaded Skills: Tracks skills loaded during the session with call counts
Cumulative Token Tracking: Accurately counts token cost when skills are called multiple times

Understanding OpenCode Skill Behavior

This section explains how OpenCode handles skills and why the token counting works the way it does.

How Skills Work

Skills are on-demand instructions that agents can load via the skill tool. They have multiple token consumption points:

Always-Available Skill Catalog: Current OpenCode versions inject a verbose XML skill catalog into the system prompt on every API call.
Skill Tool Description: The skill tool also includes a compact markdown list of available skills in its tool description, which also consumes tokens on every API call.
Loaded Skill Content: When an agent calls skill({ name: "my-skill" }), the full SKILL.md content is loaded and returned as a tool result.

Why Multiple Skill Calls Multiply Token Cost

Important: OpenCode does not deduplicate skill content. Each time the same skill is called, the full content is added to context again as a new tool result.

This means if you call skill({ name: "git-release" }) 3 times and it contains 500 tokens:

Total context cost = 500 × 3 = 1,500 tokens

This behavior is by design in OpenCode. You can verify this in the source code:

Component	Source Link
Skill tool execution	packages/opencode/src/tool/skill.ts
Tool result handling	packages/opencode/src/session/message-v2.ts
Skill pruning protection	packages/opencode/src/session/compaction.ts

Skill Content is Protected from Pruning

OpenCode protects skill tool results from being pruned during context management. From the compaction.ts source:

const PRUNE_PROTECTED_TOOLS = ["skill"]

This means loaded skill content stays in context for the duration of the session (unless full session compaction/summarization occurs).

Recommendations

Call skills sparingly: Since each call adds full content, avoid calling the same skill multiple times
Monitor skill token usage: Use TokenScope to see which skills consume the most tokens
Consider skill size: Large skills (1000+ tokens) can quickly inflate context when called repeatedly

Example Output

═══════════════════════════════════════════════════════════════════════════
Token Analysis: Session ses_50c712089ffeshuuuJPmOoXCPX
Model: claude-opus-4-5
═══════════════════════════════════════════════════════════════════════════

TOKEN BREAKDOWN BY CATEGORY
─────────────────────────────────────────────────────────────────────────
Estimated using tokenizer analysis of message content:

Input Categories:
  SYSTEM    ██████████████░░░░░░░░░░░░░░░░    45.8% (22,367)
  USER      ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░        0.8% (375)
  TOOLS     ████████████████░░░░░░░░░░░░░░    53.5% (26,146)

  Subtotal: 48,888 estimated input tokens

Output Categories:
  ASSISTANT ██████████████████████████████     100.0% (1,806)

  Subtotal: 1,806 estimated output tokens

Local Total: 50,694 tokens (estimated)

TOOL USAGE BREAKDOWN
─────────────────────────────────────────────────────────────────────────
bash                 ██████████░░░░░░░░░░░░░░░░░░░░     34.0% (8,886)    4x
read                 ██████████░░░░░░░░░░░░░░░░░░░░     33.1% (8,643)    3x
task                 ████████░░░░░░░░░░░░░░░░░░░░░░     27.7% (7,245)    4x
webfetch             █░░░░░░░░░░░░░░░░░░░░░░░░░░░░░      4.9% (1,286)    1x
tokenscope           ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░         0.3% (75)    2x
batch                ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░         0.0% (11)    1x

TOP CONTRIBUTORS
─────────────────────────────────────────────────────────────────────────
• System (inferred from API)   22,367 tokens (44.1%)
• bash                         8,886 tokens (17.5%)
• read                         8,643 tokens (17.0%)
• task                         7,245 tokens (14.3%)
• webfetch                     1,286 tokens (2.5%)

═══════════════════════════════════════════════════════════════════════════
MOST RECENT API CALL
─────────────────────────────────────────────────────────────────────────

Raw telemetry from last API response:
  Input (fresh):              2 tokens
  Cache read:            48,886 tokens
  Cache write:               54 tokens
  Output:                   391 tokens
  ───────────────────────────────────
  Total:                 49,333 tokens

═══════════════════════════════════════════════════════════════════════════
SESSION TOTALS (All 15 API calls)
─────────────────────────────────────────────────────────────────────────

Total tokens processed across the entire session (for cost calculation):

  Input tokens:              10 (fresh tokens across all calls)
  Cache read:           320,479 (cached tokens across all calls)
  Cache write:           51,866 (tokens written to cache)
  Output tokens:          3,331 (all model responses)
  ───────────────────────────────────
  Session Total:        375,686 tokens (for billing)

═══════════════════════════════════════════════════════════════════════════
ESTIMATED SESSION COST (API Key Pricing)
─────────────────────────────────────────────────────────────────────────

You appear to be on a subscription plan (API cost is $0).
Here's what this session would cost with direct API access:

  Input tokens:              10 × $5.00/M  = $0.0001
  Output tokens:          3,331 × $25.00/M  = $0.0833
  Cache read:           320,479 × $0.50/M  = $0.1602
  Cache write:           51,866 × $6.25/M  = $0.3242
─────────────────────────────────────────────────────────────────────────
ESTIMATED TOTAL: $0.5677

Note: This estimate uses standard API pricing from models.json.
Actual API costs may vary based on provider and context size.

═══════════════════════════════════════════════════════════════════════════
CONTEXT BREAKDOWN (Estimated from cache_write tokens)
─────────────────────────────────────────────────────────────────────────

  Base System Prompt   ████████████░░░░░░░░░░░░░░░░░░   ~42,816 tokens
  Tool Definitions (14)██████░░░░░░░░░░░░░░░░░░░░░░░░    ~4,900 tokens
  Environment Context  █░░░░░░░░░░░░░░░░░░░░░░░░░░░░░      ~150 tokens
  Project Tree         ████░░░░░░░░░░░░░░░░░░░░░░░░░░    ~4,000 tokens
  ───────────────────────────────────────────────────────────────────────
  Total Cached Context:                                  ~51,866 tokens

  Note: Breakdown estimated from first cache_write. Actual distribution may vary.

═══════════════════════════════════════════════════════════════════════════
TOOL DEFINITION COSTS (Estimated from argument analysis)
─────────────────────────────────────────────────────────────────────────

  Tool                Est. Tokens   Args   Complexity
  ───────────────────────────────────────────────────────────────────────
  task                       ~480      3   complex (arrays/objects)
  batch                      ~410      1   complex (arrays/objects)
  edit                       ~370      4   simple
  read                       ~340      3   simple
  bash                       ~340      3   simple
  ───────────────────────────────────────────────────────────────────────
  Total:                   ~4,520 tokens (14 enabled tools)

  Note: Estimates inferred from tool call arguments in this session.
        Actual schema tokens may vary +/-20%.

═══════════════════════════════════════════════════════════════════════════
CACHE EFFICIENCY
─────────────────────────────────────────────────────────────────────────

  Token Distribution:
    Cache Read:           320,479 tokens   ████████████████████████████░░  86.2%
    Fresh Input:           51,320 tokens   ████░░░░░░░░░░░░░░░░░░░░░░░░░░  13.8%
  ───────────────────────────────────────────────────────────────────────
  Cache Hit Rate:      86.2%

  Cost Analysis (claude-opus-4-5 @ $5.00/M input, $0.50/M cache read):
    Without caching:   $1.8590  (371,799 tokens x $5.00/M)
    With caching:      $0.4169  (fresh x $5.00/M + cached x $0.50/M)
  ───────────────────────────────────────────────────────────────────────
  Cost Savings:        $1.4421  (77.6% reduction)
  Effective Rate:      $1.12/M tokens  (vs. $5.00/M standard)

═══════════════════════════════════════════════════════════════════════════
SUBAGENT COSTS (4 child sessions, 23 API calls)
─────────────────────────────────────────────────────────────────────────

  docs                         $0.3190  (194,701 tokens, 8 calls)
  general                      $0.2957  (104,794 tokens, 4 calls)
  docs                         $0.2736  (69,411 tokens, 4 calls)
  general                      $0.5006  (197,568 tokens, 7 calls)
─────────────────────────────────────────────────────────────────────────
Subagent Total:            $1.3888  (566,474 tokens, 23 calls)

═══════════════════════════════════════════════════════════════════════════
SUMMARY
─────────────────────────────────────────────────────────────────────────

                          Cost        Tokens          API Calls
  Main session:      $    0.5677       375,686            15
  Subagents:         $    1.3888       566,474            23
─────────────────────────────────────────────────────────────────────────
  TOTAL:             $    1.9565       942,160            38

═══════════════════════════════════════════════════════════════════════════

Supported Models

Pricing data is synced from models.dev across thousands of provider/model entries:

Claude Models

Claude Opus 4.5, 4.1, 4
Claude Sonnet 4, 4-5, 3.7, 3.5, 3
Claude Haiku 4-5, 3.5, 3

OpenAI Models

GPT-4, GPT-4 Turbo, GPT-4o, GPT-4o Mini
GPT-3.5 Turbo
GPT-5 and all its variations

Other Models

DeepSeek (R1, V2, V3)
Llama (3.1, 3.2, 3.3)
Mistral (Large, Small)
Qwen, Kimi, GLM, Grok
And more...

Free/Open models are marked with zero pricing.

Configuration

TokenScope now supports a stable user override file at:

~/.config/opencode/tokenscope-config.json

On startup, the plugin loads config in this order:

~/.config/opencode/tokenscope-config.json
bundled package config: tokenscope-config.json
in-code defaults

Any missing keys are filled from the built-in defaults, so you can override only the flags you care about. This is safer than editing the file inside the global npm package directory, because npm update -g can replace that installed package and overwrite local changes.

Default flags:

{
  "enableContextBreakdown": true,
  "enableToolSchemaEstimation": true,
  "enableCacheEfficiency": true,
  "enableSubagentAnalysis": true,
  "enableSkillAnalysis": true
}

Example user override:

{
  "enableSubagentAnalysis": false,
  "enableSkillAnalysis": false
}

Set any option to false to hide that section from the output.

Troubleshooting

Command `/tokenscope` Not Appearing

Verify tokenscope.md exists:

ls ~/.config/opencode/command/tokenscope.md

If missing, create it (see Installation step 3)
Restart OpenCode completely

Wrong Token Counts

The plugin uses API telemetry (ground truth). If counts seem off:

Expected ~2K difference from TUI: Plugin analyzes before its own response is added
Approximate fallback warning: If the report says token counting fell back to approximate mode, reinstall the plugin (npm install -g @ramtinj95/opencode-tokenscope@latest) or rerun ~/.config/opencode/plugin/install.sh
Model detection: Check that the model name is recognized in the output

Privacy & Security

All processing is local: No session data sent to external services
Open source: Audit the code yourself

Contributing

Contributions welcome! Ideas for enhancement:

Historical trend analysis
Export to CSV/JSON/PDF
Optimization suggestions
Custom categorization rules
Real-time monitoring with alerts
Compare sessions
Token burn rate calculation

Support

Issues: GitHub Issues
Discussions: GitHub Discussions

Name		Name	Last commit message	Last commit date
Latest commit History 114 Commits
command		command
plugin		plugin
scratch		scratch
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md

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