ResearchToken Optimization Techniques

Token-Optimization Techniques — Research Dossier

Token-Optimization Techniques — Research Dossier

Definitive research dossier on extreme token-optimization techniques for coding-agent usage at zero quality loss. Every external claim carries a source URL; every local number carries its method. Specification: prompt.md. This dossier is one of three separated researches: techniques (this folder), the token-optimization tools hub (per-tool teardowns, including the former Volume III chapters, now tools-hub chapters 19 — Code-intelligence tools through 25 — sem and mq), and the jackin Context Engine spec.

Headline numbers

  • 10x verdict: not defensible at zero quality loss today. Defensible: ≈2.5x with validation (Aggressive stack; ≈2.4x on code-heavy mixes), ≈5–6.2x if the Sonnet-main+advisor routing flip passes the harness on your tasks. Binding constraints: frontier-model thinking output, then the cache-read floor of genuinely-used context. (15)
  • Where money went in the measured heavy session: cache reads 32% / cache writes 29% / thinking ~20% / visible output ~17% / uncached 2%; an independent session measured output-heavy instead. Stable invariant: cache reads dominate token volume, while output + cache writes dominate dollars. (02, 28)
  • Defaults already bank ~4–5x: caching measured −86.3% input-side this very session; MCP schemas defer by default; Edit-diffs are default. Much of the market re-sells these. (07, 06)
  • Caveman-ultra measured 58.5% token cut on visible prose (claims say 65–75%); wenyan's 80.9% char cut collapses to 56.6% tokens. Style compression caps at ~17% of dollars — and at 1.4–1.5% of visible output in tool-heavy sessions. (02, 04)
  • Strongest sanctioned lever on thinking: effort (T1: Opus 4.5 medium = equal SWE-bench at 76% fewer output tokens). Strongest input lever: context architecture (tool search 85% cut with accuracy 49%→74%; context editing 84% cut with +29% performance). (09, 06)
  • Fable 5/Opus 4.8 tokenizer bills ~30% more tokens on English/ASCII-heavy text, but the premium is near-neutral on code/CJK probes — cross-tier routing saves list price on code-heavy work (Fable→Sonnet ≈ ÷3.3) and up to ≈÷4.3 on prose/markdown-heavy text. (05, 10, 28)

How to read

Numbering map

All dossier files were renumbered to a strictly sequential scheme on 2026-07-05, and every in-prose file reference in this research now uses the new numbers. The frozen brief (prompt.md) and any external citations written before that date still use the original scheme — translate via the table below (files 0003 are unchanged).

OldNew
1004
1105
1206
1307
1408
1509
1610
1711
1812
1913
2014
3015
3116
3217
4018
4119
4220
4321
4422
4523
4624
4725
4826
4927
5028

The former Volume III chapters 51–57 left this dossier entirely and now live in the token-optimization tools hub as chapters 19 — Code-intelligence tools through 25 — sem and mq.

Tier list

value = expected $ saving on the modeled profile × confidence (evidence tier) ÷ adoption effort

TierTechniques (file)
STool search / MCP schema deferral (06) · context editing + observation masking (06/08/12) · effort tiering incl. max→high (09) · subagent model+effort pinning (10) · Edit-over-Write + no-restatement guards (09) · advisor-pattern escalation (10) — all NEGATIVE-COST or vendor-validated
ACache hygiene: task-boundary model/effort switching only (10/07) · batch lane for offline work (12) · repo-maps/outlines instead of file dumps (06) · structured-output sidecars (09) · state-file session resume (08) · register compression in chat-heavy workflows (04)
BStructured-data format choice — CSV/compact lines/TOON (05) · pointer architecture & lazy instruction loading (08) · session codebooks (14) · ID/timestamp hygiene — epoch, surrogate IDs (05) · hook dedup and prefix audits (02/06) · CI token-budget linter (14)
CRegister compression in tool-heavy workflows — ceiling ~0.4% of output (02/04) · identifier-casing policy, design-time only (05) · instruction-side register compression — 50x less valuable per token than output side (04) · prefill for non-thinking sidecars, dying (09)
FWenyan registers — no token gain over ultra, higher risk (02/04) · LLMLingua-style proxy for coding (13) · semantic response caches for agents (08) · cache-keepalive pingers for Claude Code (14) · base64/gzip "compression" — costs 2.7–4.3x MORE (13) · cl100k-based "Claude calculators" (05) · max_tokens as an optimizer (09) · glyph/symbol prompt DSLs (04)

Assumptions (judgment calls made during the run)

  1. All "current" claims were verified against live provider documentation.
  2. No ANTHROPIC_API_KEY present; the free count_tokens endpoint was called with the Claude Code OAuth credential already on this machine (no billable usage). The brief explicitly mandates count_tokens use.
  3. Only this run's transcripts existed locally; thinking-share and session decomposition are n=1-environment measurements (max-effort main loop + a 25-agent fleet), labeled as such wherever used.
  4. "Deliverables exactly as specified" = the 19 files of §10 and nothing else in the folder; measurement scripts are embedded in reports as reproducible snippets.
  5. Operator mid-run instructions were folded in: (a) cavemem / cavekit / fff and the industry-standard/proven/engineer-verified buckets → 03 — Prior art and market scan; (b) the request to "add this to token-optimization.md" was interpreted as the dossier (the brief forbids modifying pre-existing repo files, including the brief itself); (c) chat output kept in caveman-ultra; dossier files follow the brief's own writing rules (plain language, full sentences) as the deliverable spec.
  6. Heavy-day profile band: $17/day (5 sessions, 45% thinking) floor and $22/day (6 sessions, 55% thinking) working figure; area files and stack math use $22; ratios are profile-invariant. (01 §5)
  7. Mid-run, five workflow draft agents died on a session rate limit (reset 19:20 UTC); the run continued on usage credits per the operator's local action. 11 — Multi-agent protocols and 14 — Frontier were re-drafted from the already-completed research JSON by follow-up agents.
  8. An environment quirk repeatedly deleted freshly-written untracked files in the worktree (subagent cleanup race). Countermeasure: every artifact was committed from the main process within seconds of landing, and two files were restored from agent-transcript payloads. No content was lost; the incident is noted because it shaped the commit cadence.

Self-audit against the Definition of Done

  • All 19 files of §10 exist and follow the writing rules (TL;DR ≤5 bullets with numbers, tables, tiers on every claim); README carries tier list, headline numbers, Assumptions.
  • ≥40 techniques across files 04 — Style and Language Compression — Beyond Caveman through 13 — Infrastructure-level (self-hosted / gateway tier): 110 cataloged, every one carrying the full record schema including a validation protocol (≥15 complete required — far exceeded).
  • ≥10 frontier ideas: 12 in 14 — Frontier — unrealistic but maybe real, each with mechanism → math → feasibility verdict.
  • Phase-0 baseline audit with real measured numbers: agent rule chain token masses, the 6×7 caveman/wenyan tokenizer table, MCP schema costs, hook-duplication waste, thinking-vs-visible decomposition (54.8%) with the transcript-redaction workaround documented (02 — Baseline Audit of This Environment (Phase 0)).
  • Headline numbers survived the adversarial pass: agent-reported local measurements spot-reproduced (arrow/casing/epoch checks — 3/3 confirmed), primary sources re-fetched independently (pricing, caching, CoD, RouteLLM, LLMLingua, aider, multi-agent 15x), internal contradictions reconciled (profile band, tokenizer-gap range stated as range). Claim graveyard included (00 §graveyard + per-file kill tables, incl. corrections to the operator's own plugin claims: 75%→58.5% visible-prose, cavecrew 60%→43.9%).
  • Three composed stacks with end-to-end dollar math and an explicit 10x verdict + named binding constraint (15 — Composed Stacks: Conservative / Aggressive / Unbelievable).
  • Negative-cost set explicitly identified (15 §4: eight techniques).
  • 16 — Validation Harness: the No-Quality-Loss Proof Protocol runnable as written: task table with objective checkers, six canary classes with assertions, headless runner script, bootstrap decision rule.
  • 17 — Adoption Roadmap: Day 1 / Week 1 / Month 1 separates automatic (hooks/skills/plugin/jackin-baked, with in-repo insertion points) from discipline-dependent adoption, day-1/week-1/month-1.
  • Every external claim has source + access date; every measurement has its method (per-file Verification ledgers).
  • Every artifact landed as an incremental commit pushed to origin on chore/token-optimization — 20+ commits over the run, no end-of-run dump; final state pushed.
  • This self-audit appended to README with each box checked honestly. Known limits, stated: thinking-share is n=1-environment; the 76% effort figure is Opus 4.5-only pending local transfer validation; stack totals are ESTIMATE arithmetic on a modeled profile — the harness in 16 exists precisely to convert them into your numbers.

Volume II — Extension

**(Volume I froze; all Volume II claims pinned to 06-13 with drift delta, sources + access dates in each file's ledger). Volume II is an additive layer on top of the frozen Volume I (files 00 — Executive Summary through 17 — Adoption Roadmap: Day 1 / Week 1 / Month 1 unedited); it fills the gaps Volume I left blank or drew too thin. Governing gap audit and extension scope: 18 — Volume II extension: gap audit and blind-spot map.

Volume II index (18–27 band)

Volume II headline numbers

  • 10x dollar verdict unchanged: ≈2.5× / ≈5–6.2× with validated routing / no true 10×. No Volume II lever removes Volume I's binding constraints (frontier-model thinking output; the cache-read floor). (27)
  • The metric is wrong for a subscriber. The local credential is Max; below the cap dollars are sunk and the objective is tasks-per-cap. Volume II ships a second (quota) cost model alongside the dollar model. Cap cache-read weight ≈ 0.1× (community-triangulated, T3); the cap token denominator is unpublished (bounded INCOMPLETE). (19)
  • Multimodal, measured (count_tokens): image = ⌈w/28⌉·⌈h/28⌉ visual tokens, with high-resolution caps around ~4,760 (Opus/Fable) vs ~1,520–1,570 (Sonnet/Haiku), a ~3.0–3.1× per-image divergence; PDFs cost ~3,150 tok/page and ~2× the equivalent text (the "PDF tax"); a screenshot of textual content is 2–6× the text it shows. (20)
  • Latency is priceable: the same Opus 4.8 spans 4× on the latency axis (batch $2.50 / standard $5 / fast $10 input); buy speed only when a human is blocked (v·t·s > Δ$). (21)
  • Drift since 06-12 (Volume II state; the current picture is in 28): at Volume II research time count_tokens rejected Fable 5 (Opus 4.8 was the tokenizer-twin proxy; it accepts claude-fable-5 directly as of 2026-07-05) and Fable 5 was slated to leave the subscription 06-23 (it was instead suspended 06-12→30 under an export-control directive, then restored 07-01 with 50%-of-weekly-cap plan inclusion through 07-07); 5-hour limits doubled (effective 2026-05-06); the announced headless/SDK off-cap billing split was paused before rollout — headless still draws the interactive cap; KV-eviction family (SnapKV/H2O/PyramidKV/KVQuant) and CAG are real but self-host-only on hosted Claude. (19, 24, 28)
  • 50 genuinely-new techniques (42 in files 19 — Subscription & quota economics: the metric Volume I optimized was the wrong one for a subscriber through 25 — Meta layer: the cost of optimizing, budget governance, and online quality guarding with the full §10 record + 8 frontier), each with a coverage-delta note proving absence from 00–17. (27)

Blind-spot map (summary)

Eight seeded blind spots audited by overlaying an independent taxonomy on Volume I (14-agent coverage sweep + grep). Five confirmed thin/absent → full area files: quota (19), multimodal (20), latency-axis (21), portability (23 — no matrix existed), governance + online-quality (25). Three partial → sharpened: fleet (22 — self-host done in 13; hosted sharing was thin), fresh-lit (24 — strong scan, specific holes), and Volume I's own open questions (worked and distributed, collected in 27). Full map with file:line evidence and per-cell stake: 18 — Volume II extension.

Verdict delta (one line)

Dollars: no change (≈2.5× / ≈5–6.2× / no 10×, arithmetic in 27/28). Metric: changed — for a subscriber optimize tasks-per-cap, where the lever order re-sorts (prefix stability, window size, request-volume up; subagent fan-out partially inverts; style compression matters even less). Volume I's Fable-priced dollars are ~2× high for the operator's actual Opus 4.8, but ratios/tiers are unchanged.

Volume II Assumptions (judgment calls)

  1. Research date. Drift delta done; the load-bearing drift (Fable 5 not count_tokens-able; Fable promo ends 06-23; 5-hour doubling; 06-15 SDK split) is flagged where used.
  2. Instrument: count_tokens via the OAuth credential (claudeAiOauth.accessToken), free/non-billable, rebuilt at /tmp/ct.py (Volume I's copy did not persist — fresh container). Fable-family tokenizer measured on claude-opus-4-8 (its documented twin), labeled wherever used.
  3. Local environment: Opus 4.8 main + Haiku 4.5 subagents, effort=max, Max subscription (~/.claude/.credentials.json). Token-class decomposition from 31 transcripts / 560 calls.
  4. Test media (images/PDFs) generated from the Python stdlib (zlib) — no PIL/ImageMagick on the box — and validated against 5 real repo PNGs and Anthropic's published cost table; the image curve was adversarially re-confirmed with a max-entropy noise image (content-independent).
  5. Quota model carries a bounded INCOMPLETE: the cap token denominator and the exact cap cache-read weighting are unpublished (confirmed across 6 primary pages + 3 GitHub issues). The ~0.1× weight is community-triangulated (T3); true cap-% needs the unified-* response headers (/usage or a proxy), not run this pass (frontier V2).
  6. Open questions still open (honestly): the effort→thinking-share curve (all local transcripts are a single effort level — unmeasurable this run), the per-account cap denominator (needs a header- reading proxy), and the exact SDK excludeDynamicSections byte size (reconstructed estimate ~111 tokens). Each is flagged in its file.
  7. Seven area files (19–25) were written, exceeding the ≥5 floor; fleet (22) was kept distinct (not merged) because the hosted-fleet material proved genuinely separate from 13 — Infrastructure-level's self-host tier.
  8. Multi-agent machinery: an E0 coverage-map workflow (14 read-only readers) and an E1 fresh-sweep workflow (11 web-research streams); all deliverables were written and committed from the main process within seconds of landing (Volume I's file-deletion-race countermeasure).
  9. Cache-layer and subagent-caching caveats (22/27): the hosted server prompt cache is workspace-scoped, not machine/dir-keyed; subagent caching can be version-dependent — audit your own JSONL before relying on it.

Volume II self-audit against the Definition of Done

  • Blind-spot map built by overlaying an independent taxonomy on Volume I with file:line evidence of thin/absent coverage (18 — Volume II extension).
  • ≥5 new area files (19–25 = seven), writing rules followed; ≥25 new techniques (50, each with a coverage-delta note); ≥10 with the full record (all 42 in 19 — Subscription & quota economics through 25 — Meta layer carry it). (27 — Volume II capstone ledger)
  • ≥6 new frontier ideas with feasibility verdicts + math (8 in 26 — Volume II frontier).
  • Subscription/quota cost model delivered with an explicit bounded INCOMPLETE naming the unpublished denominator and what was measured instead (19 — Subscription & quota economics).
  • Multimodal/vision/PDF token costs measured locally via count_tokens with the method shown (zlib-generated assets, validated against real PNGs + the published table) (20 — Multimodal token economics).
  • Every Volume II headline number survived the adversarial pass; the two most novel were re-attacked (noise-image content-independence; PDF tax across content). Volume II graveyard included (27 — Volume II capstone).
  • Verdict delta with arithmetic — dollars unchanged, metric reframed for a subscriber (27 — Volume II capstone).
  • Cross-layer caveats captured in 27 — Volume II capstone (cache scope, subagent caching).
  • Every external claim has a source; every measurement its method (per-file Verification ledgers).
  • Every artifact committed and pushed to origin on chore/token-optimization as it landeddocs(research): … Conventional Commits with DCO sign-off, no CI wait, no end-of-run dump.
  • Volume II self-audit appended here, each box checked; judgment calls in the Volume II Assumptions section above. Honest residual gaps named in Assumption 6.

Volume III — tooling and external-tool comparison

Adds runnable measurement scripts and a comparison of external code-search / code-intelligence tools.

The Volume III per-tool chapters (19–25) now live in the dedicated token-optimization tools research as part of the three-way research split (techniques / tools / engine spec). That hub consolidates the equal-depth design teardowns of caveman, headroom, RTK, and lean-ctx (the integrated context runtime added in a later round), a feature has/lacks matrix, best-case-of-each, and a straight answer to whether one product can combine them all. The summaries below link to the chapters' new homes; only the runnable tools/ instruments remain in this folder.

  • Runnable tools/count_tokens.py, image_tokens.py, session_cost.py reproduce the dossier's core numbers against the live Anthropic tokenizer: real token counts, the image-token formula, and the dollar/token split deduplicated by message.id.
  • 19 — Code-intelligence tools: codedb, fff, CodeGraff, and alternatives — deep dive comparing codedb, Codegraff, and fff — whether they help AI coding agents and save tokens. They productize the same context-architecture lever (serve outlines/symbols, not whole files), measured locally at ≈91% (outline) / 98% (symbol search) fewer tokens than reading the file; with setup recipes and the MCP-schema-overhead caveat.
  • 20 — Qdrant and vector databases for agent context — Qdrant/vector DB follow-up: vector search is an optional semantic-memory/RAG backend, not a replacement for fff or codedb. Default recommendation remains rust-analyzer + ast-grep + codedb + fff; pilot Qdrant only for docs/examples/decisions/pattern recall and accept it only if it beats that planned stack by ≥20% tokens per solved task at equal quality.
  • 21 — Headroom and the context-compression layer (vs the caveman ecosystem) — deep dive on chopratejas/headroom (the input-side context-compression layer); the cross-tool comparison to the caveman ecosystem and RTK is consolidated in the dedicated token-optimization tools folder. Headroom compresses what the model reads (tool outputs/logs/RAG/files, the 61% cache buckets); caveman compresses what the model writes (prose, 17%) — orthogonal, they stack, neither touches thinking (20%). Headroom's live-zone design (stabilize the cached prefix, compress only the volatile tail) is the cache-safe input-compression design that refines the record-19/FL3 "no compressor in the hot path" kill; its "60–95%"/"96.2%" headlines are per-payload/double-counted and corrected here (K1-style). Verdict: pilot MCP mode as an A/B arm against existing hooks (record 20) + code-intelligence (19) + serialization (record 14); never default the whole-prompt proxy in a jackin container.
  • 22 — Context-compression literature and market delta (2024–2026) — the compression-layer internet re-sweep (other projects) + fresh literature (2024–2026), companion to 21. Headline: a cache-safety classification of every compression move (output brevity = cache-neutral; write-time observation compression = safe; whole-prompt input compression = breaks the cache, must beat ~10×). The frontier moved to code-domain, hosted-viable, write-time compressors that raise SWE-bench accuracy (Squeez, AgentDiet, SWEzze, SWE-Pruner, LongCodeZip) — refuting 24 — Fresh literature & market delta (clean-room re-sweep)'s "no compressor safe for code." Stars are a PR artifact in this niche; rank by evidence. Credible challengers (the-complexity-trap, OpenHands batched condensation, ACON, llmtrim, claw-compactor) ranked by evidence, not stars.
  • 23 — Token observability and session visualization (token-optimizer and peers) — the observability layer (distinct from compression): a deep dive on alexgreensh/token-optimizer and a survey of full-per-token-visibility / session-visualization tools. token-optimizer reads Claude Code JSONL transcripts locally (no proxy, cache-safe) and renders the dossier's own per-turn input/output/cache-read/cache-write decomposition as a web dashboard + status line — it productizes tools/session_cost.py with a UI. Key limit: thinking stays invisible in any JSONL-only tool (must be inferred via count_tokens). Caveats: PolyForm-Noncommercial license; dollar views assume API pricing, not a Max subscription (19 — Subscription & quota economics: the metric Volume I optimized was the wrong one for a subscriber). The JSONL-reading, no-proxy class is the safe measurement front-end of the validation harness.
  • 24 — RTK and write-time observation compression — deep dive on rtk-ai/rtk ("Rust Token Killer") — the dossier's RTK record. The cross-tool comparison it originally carried now lives, expanded to four tools (adds lean-ctx), in the dedicated token-optimization tools folder (single source of truth). RTK is the deterministic, Claude-Code-native productization of the cache-safe write-time observation-compression design point 21 — Headroom and the context-compression layer (H1) and 22 — Context-compression literature and market delta named: it compresses shell-command output (tests/git/logs/builds) at the tool boundary via a PreToolUse hook — no ML, no MCP rent, cache-safe by construction — but reaches only Bash calls (not native Read/Grep). The "60–90%" is a per-command best case (no whole-session telemetry, no independent benchmark; 63.5k★ is PR-inflated per 22 — Fleet, team & multi-tenant cache economics (hosted) §A), corrected to low-double-digit whole-bill, same as the caveman K1 / headroom H-K1 moves. Verdict: caveman for output; RTK and headroom are complementary input-side layers (RTK = Bash output at the tool boundary, headroom = API-layer everything-else) the community stacks — a published month-long head-to-head measured RTK 1.33B + headroom 0.19B → 1.52B tokens, headroom at 96% prefix-cache-hit (confirming the live-zone design); adopt in risk/reach order. RTK is the most container-adoptable of the three, pilot it role-scoped with the host-write/hook-conflict guardrails. 19 — Subscription & quota economics's ast-grep coverage was also extended into a full verdict (structural-search token economics + the skill-vs-MCP-vs-CLI form-factor analysis).
  • 25 — sem and mq: entity-level retrieval and structural markdown queries — 2026-07-03 addendum covering two tools the dossier had missed: sem (entity-level diff/impact/context on tree-sitter entities; sem-core is a real crates.io library; its attention ledger — tracking what the agent's context already holds and suppressing re-sends with ≡ unchanged stubs and entity-level delta-fills — is the one genuinely novel mechanism in the 2026 tool wave) and mq (jq for Markdown; mq-lang/mq-markdown crates, nushell-proven), whose TOC-then-section retrieval (measured 12–53× on 11–15 KB docs) is the first surveyed lever for the docs/prose read bucket that dominates this repo's own measured observation traffic (76.2% native reads). Reuse verdicts feed the jackin Context Engine spec; same-date deltas for caveman/headroom/RTK/lean-ctx live in tools hub 13.

Volume IV — drift delta (2026-07-05)

Chapter 28 — Drift delta is a drift pass: the dossier's load-bearing external claims (model lineup, pricing, tokenizer families, count_tokens behaviour, context-management betas, subscription/quota rules, Claude Code changelog) checked against live sources on 2026-07-05. The pass found nine load-bearing deltas — headline items: Claude Sonnet 5 shipped 2026-06-30 (new tokenizer family, $2/$10 intro pricing, new Claude Code default), the 2026-06-15 headless/SDK quota split was paused before rollout, the Explore subagent no longer defaults to haiku as of 2.1.198, and the memory tool went GA. The dossier's headline verdict — no defensible 10x at zero quality loss — stands; the deltas change model-tiering, tokenizer-arbitrage, and quota-routing arithmetic in 05 — Tokenizer arbitrage, 06 — Context architecture, 08 — Retrieval, memory, and state offloading, 10 — Model routing and tiered delegation, 19 — Subscription & quota economics, and 24 — Fresh literature & market delta, and every Sonnet-based arbitrage claim must now be pinned explicitly to Sonnet 4.6/Haiku 4.5.

Final completion audit


Addendum — Code Intelligence Tools

Focused live analysis requested after the final audit, then expanded with an internet re-sweep for alternatives: 19 — Code-intelligence tools: codedb, fff, CodeGraff, and alternatives compares codedb, fff, the CodeGraff codedb article, the CodeGraff product/toolchain, and stronger alternatives such as Serena, Code Context Engine, Augment Context Engine, Sourcegraph MCP, Qodo Context Engine, Claude Context, and CodeGraphContext.

  • Verdict: these tools can save tokens only when they replace blind grep/read loops with bounded, precise retrieval. codedb has the strongest public token-saving case; fff has a strong latency case and plausible but unquantified token savings; Serena is the strongest local open-source semantic-navigation challenger, Code Context Engine has the strongest local open-source token-savings headline with baseline caveats, and Augment/Sourcegraph/Qodo are stronger commercial or enterprise context systems if vendor dependency is acceptable.
  • jackin recommendation: keep the existing the-architect fff pilot, add a measured codedb A/B arm if MCP schema overhead is deferred or bounded, add Serena/Claude Context competitor arms where installable, include Code Context Engine in the token benchmark, and treat CodeGraff Pro/Augment/Sourcegraph/Qodo as explicit opt-in agent-stack experiments rather than default jackin-core dependencies.
  • Qdrant follow-up: 20 — Qdrant and vector databases for agent context concludes Qdrant is a credible backend for semantic memory/RAG but should stay optional and scoped; a live check found Milvus/Zilliz, Vespa, Turbopuffer, LanceDB, Chroma, Pinecone, and pgvector are real alternatives, but none proves better coding-agent token economy than fff + codedb. The useful local case is a bounded hybrid docs/decision index over the repo's large documentation surface, not default code navigation. Qdrant should not become a default third tool unless a harness proves a ≥20% token-per-solved-task reduction against the planned stack.

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