Where the measured money is
- Fresh sessions with a handoff past 150,000 to 200,000 tokens
- Lean always-loaded instructions
- Partial file reads
- Tool output to files, summaries back
- Fewer tool, skill and MCP listings
- Subagents for searches and scans
Every call to a frontier model re-sends the whole conversation. A long session pays for its own history again and again. This page shows what we measured on a real account, what Workboard's rules found, and what a change in habits is worth at the scale of a company.
Thirty days, one account, 89,928 API calls, about $7,760 at API list prices. Cache reads were 15.9 billion of 16.5 billion tokens. On average each call re-read about 177,000 tokens of context. Output, the part people think of as the answer, was under half a percent.
cost ≈ calls × context per call × price per token
Cache reads cost about a tenth of fresh input per token, which is why they are 96% of tokens but a smaller share of dollars. They are still the largest single cost.
Most of it came from oversized context. Estimates overlap where one call breaks two rules, so treat the total as a guide. Loops, the same call repeated with nothing changed, are a twelfth finding shown on the Savings page.
| Rule | What it detects | Findings | Estimated | Advice it gives |
|---|---|---|---|---|
| Big context | Calls whose context is over 200,000 tokens | 391 | $835 | Start a fresh session or agent with a short handoff |
| Cache lifetime | A subagent idle past its five-minute cache, then writing it again | 8 | $380 | Run long waits as a detached job with a watcher; end the agent |
| Effort | High effort on short tool-only turns of a heavy model | 662 | $192 | Run mostly-tool work at lower effort |
| Unused MCP | An MCP server loaded and never called | 91 | $13 | Switch it off where it is not used |
| Idle compaction | Auto-compaction with no prompt in the 30 minutes before | 23 | $3 | End or clear a session you have left |
| Compactions | Two or more compactions in one session | 5 | $2 | Smaller briefs, or compact earlier |
| Cold switch | Model switched mid-session with a cold cache | 1 | $0.65 | Pick the model at the start, or switch in a fresh session |
| Permission wait | Over five minutes waiting on permission prompts | 13 | - | Allow the commands you always approve |
| Tool failures | A tool failing over 10% of its calls | 6 | - | Check how it is called: path, missing tool, flaky command |
| Cache misses | Over five cache misses in a session, by cause | 8 | - | Keep tools, model and system prompt fixed in a session |
| Retries | API errors over 5% of a session's calls | 1 | - | Look at the errors; overload eases off a busy hour |
Each MCP server, plugin and skill adds its tool schemas or description to every call. An invoked skill's whole body stays in context for the rest of the session and is re-attached after compaction. An agent saves context when it returns a conclusion and ends; it costs the most when it waits, grows or gets resumed. A call at 600,000 tokens of context costs about 15 times a call at 40,000, and a watcher agent that wakes every few minutes pays that on every wake.
Workboard shows the MCP load against calls, the largest tool outputs, agent types by cost and context, and the loops, so the fix is a setting or a habit rather than a guess.
Enter your annual frontier model spend and the number of developers behind it. The avoidable share defaults to the 18% our rules priced on a real account over 30 days; move it to whatever you find credible.
Tell us how many developers use Claude Code and where you would run Workboard. A person at Cognitivi reads every message, replies by email and walks you through the page on your team's data.