Phase 8 formulate manifest + PHASE0 §11 amendment to add the Phase 8
row (substrate amendment per CLAUDE.md §3 lands same commit).
Four pillars:
1. Per-endpoint /tokenize probe (cached). One round-trip on first
call per (endpoint, model); capability cached for session.
hossenfelder + llama.cpp expose <endpoint>/tokenize (NOT /v1/
tokenize — per real probe; the path is endpoint-local, not
under the OpenAI /v1 prefix). Cloud (OpenRouter) 404s — silent
char/4 fallback.
2. broker.token_count(model_cfg, text) — thin wrapper; tries probe,
falls back to char/4 on miss. Always returns non-negative int;
never errors. 2s tight timeout; failures cache as not-supported.
3. Context:estimate_tokens widened. Accepts optional tokenize_fn at
Context.new; uses it when present, char/4 otherwise. repl.lua
wires `tokenize_fn = function(text) return broker.token_count(
active_cfg, text) end` when cfg.tokenize.use_endpoint = true.
Per-turn _tokens cache to amortize across estimate calls.
4. :cost detail est-vs-actual annotation. When the heuristic
disagrees with the actual prompt_tokens from broker usage by
>10%, show `~est=N`. Silent otherwise. Display-only; no
behavior change.
Resolves Q1 (PHASE0 §13, originally Phase 3) — replace char/4
heuristic on Context:estimate_tokens. Originally targeted at Phase 3
but deferred forward each iteration; now lands.
Baseline already observed during formulate:
- /v1/tokenize -> 404 on hossenfelder; /tokenize -> works
- Body shape: {content: "..."} returns {tokens: [N1, N2, ...]}
- Accuracy gap: char/4 UNDERESTIMATES by ~10% on real code/prose
(508 vs 558 on a 2KB README sample). Material for context-
budget eviction decisions.
Doc covers scope + done-when, tech decisions table, module changes,
per-pillar deep dives, UX surface, out of scope, 6 risk rows, 6
open questions (Q-T4/T5 baseline-bound, others analyze-bound).
Scope confirmed via AskUserQuestion: tokenization (chosen over
cross-session cost persistence and hard rate-limit enforcement).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
