toolcall-stats

An OpenCode plugin that profiles tool calls - tracking duration, frequency, argument/result sizes, and error rates.

• Tracks every tool call OpenCode makes (bash, read, write, grep, glob, etc.)
• Records duration, argument size, result size, and error status
• Per-tool breakdown: calls, errors, average time, total time
• Persistent JSONL metrics and summary JSON
• CLI tool for viewing stats
• Zero dependencies

The plugin hooks into OpenCode's supported hooks:

• tool.execute.before - captures start time, tool name, and arguments
• tool.execute.after - computes duration, result size, error status, appends to metrics

Data is stored in ~/.config/toolcall-stats/:

• metrics.jsonl - one JSON entry per tool call
• summary.json - aggregated stats

Global CLI commands:

npm install -g toolcall-stats

OpenCode plugin: add to your opencode.json:

{
  "plugin": ["toolcall-stats"]
}

• tc-stats - Show summary table
• tc-stats --recent - Show recent calls
• tc-stats --stats - Show advanced stats (percentiles, median, stddev, slowest)
• tc-stats --json - Output raw JSON
• tc-stats --reset - Clear all data
• tc-report - Detailed terminal report
• tc-viz - Generate HTML dashboard

Tool Call Profiler - Summary

  Tool calls:         1,247
  Errors:             23 (1.8%)
  Total duration:     5.2m
  Avg duration:       251ms
  Total args size:    2,458,921 chars
  Total result size:  8,234,561 chars

  Calls by tool:
  Tool                  Calls  Errors    Avg Time   Total Time
  bash                    423       2       180ms        1.3m
  read                    389       0        45ms       17.5s
  grep                    201       5        12ms        2.4s

metrics.jsonl (one per line):

{"ts":"2026-05-28T16:45:02.000Z","tool":"bash","duration":182,"argsChars":1423,"resultChars":8921,"error":false}

summary.json:

{
  "totalCalls": 1247,
  "totalDuration": 312000,
  "totalErrors": 23,
  "totalArgsChars": 2458921,
  "totalResultChars": 8234561,
  "byTool": {
    "bash": { "calls": 423, "errors": 2, "totalDuration": 78000, "totalArgsChars": 890000, "totalResultChars": 3400000 },
    "read": { "calls": 389, "errors": 0, "totalDuration": 17500, "totalArgsChars": 450000, "totalResultChars": 2100000 }
  },
  "firstCall": "2026-05-28T14:23:11.000Z",
  "lastCall": "2026-05-28T16:45:02.000Z"
}

# Longest-running tool calls
cat ~/.config/toolcall-stats/metrics.jsonl | jq -s 'sort_by(-.duration) | .[0:5]'

# Error rate by tool
cat ~/.config/toolcall-stats/metrics.jsonl | jq -s 'group_by(.tool) | map({tool: .[0].tool, errors: map(select(.error)) | length, calls: length}) | sort_by(-.errors)'