Fresh-Session Token Baseline (31K)
- Entity ID:
ent-20260419-b8d0f2c4e6a8 - Type:
concept - Scope:
shared - Status:
active - Aliases: zero-message baseline, session startup cost
Description
Measured token consumption of a Claude Code session before any user work: ~31K tokens composed of system prompt (4.3K), built-in system tools (20.3K for ~40 tools), MCP tools (~905), custom agents (1.6K), memory files (1.6K), and skills (2.3K). Documented in GitHub issue #24243. Establishes the floor against which per-turn costs must be measured and makes visible why the effective window is smaller than the nominal 200K.
Key claims
- none yet
Relations
- Fresh-Session Token Baseline (31K) --[derived_from]--> System Prompt Assembly