/cost -- Session & Campaign Cost Explorer

When to Use

• /cost -- current session cost and burn rate
• /cost today -- today's total spend
• /cost week -- this week's spend
• /cost campaign {slug} -- total spend for a specific campaign
• /cost all -- lifetime cost summary
• When /do routes "how much", "what's the cost", "spending", "tokens", "burn rate"

Inputs

Optional arguments parsed from user message:

• today -- filter to today's sessions
• week -- filter to last 7 days
• campaign {slug} -- filter to a specific campaign
• all -- show all-time data
• No argument -- show current session

Protocol

Step 1: READ REAL DATA

Run the session-tokens.js script to get real token data:

node scripts/session-tokens.js              # current/latest session
node scripts/session-tokens.js --today      # today's sessions
node scripts/session-tokens.js --all        # all sessions (use for week/all/campaign)

Also read:

• .planning/telemetry/cost-tracker-state.json for live burn rate
• .planning/telemetry/session-costs.jsonl for campaign attribution
• scripts/pricing.json to show which pricing is being used

If session-tokens.js is not available or fails, fall back to session-costs.jsonl data and clearly mark output as "(estimated)".

Step 2: RENDER BASED ON SCOPE

Current session (/cost with no args):

=== Session Cost Report ===
Session: {sessionId (first 8 chars)}
Started: {relative time} ({absolute time})
Duration: {minutes} min

Tokens:
  Input:          {N} tokens
  Output:         {N} tokens
  Cache creation: {N} tokens
  Cache read:     {N} tokens
  Total:          {N} tokens

Cost: ${total}
Burn rate: ${rate}/min
Messages: {N} ({N} main + {N} across {N} subagents)

Model breakdown:
  claude-opus-4-6:         {N} messages (${cost}, {pct}% of spend)
  claude-haiku-4-5:        {N} messages (${cost}, {pct}% of spend)