marketing-shibata50/claude-code-ultimate-guide
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

docs: enrich 200K vs 1M section with community findings

Browse source 
- Add community verdict: 1M is niche premium, not default
- Add Gemini 1.5 Pro comparison ($3.50/$10.50 vs Opus $10/$37.50)
- Expand decision table: full-repo audit vs RAG vs refacto
- Add Sonnet 4.6 community report on precision degradation at 1M
- Add "check context at 70%, open new session" workaround pattern (HN)
- Add links to HN validation test + independent MRCR analysis

Sources: Perplexity deep search Reddit/HN/blogs, Feb 18 2026

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Florian BRUNIAUX 2026-02-18 10:43:46 +01:00
parent 8d6c50403d
commit 61d7bb5fad
1 changed files with 12 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

18
guide/ultimate-guide.md
View file

@ -1753,21 +1753,21 @@ Claude Code uses **Claude Sonnet 4.6** by default (as of Feb 2026):
#### 200K vs 1M Context: Performance, Cost & Use Cases
The 1M context window (beta, API + usage tier 4 required) is a significant capability jump — but it's not always the right choice.
The 1M context window (beta, API + usage tier 4 required) is a significant capability jump — but community feedback consistently frames it as a **niche premium tool**, not a default.
**Retrieval accuracy at scale (MRCR v2 8-needle 1M variant)**
| Model | 256K accuracy | 1M accuracy | Source |
|-------|--------------|-------------|--------|
| Opus 4.6 | 93% | 76% | Anthropic blog + independent analysis (Feb 2026) |
| Opus 4.6 | 93% | 76% | Anthropic blog + [independent analysis](https://www.youtube.com/watch?v=JKk77rzOL34) (Feb 2026) |
| Sonnet 4.5 | — | 18.5% | Anthropic blog (Feb 2026) |
| Sonnet 4.6 | Not yet published | Not yet published | — |
Note: Opus 4.6 retains strong accuracy at 1M (76%), Sonnet 4.5 degrades sharply. The benchmark is the "8-needle 1M variant" — finding 8 specific facts in a 1M-token document. The 93% figure at 256K comes from independent analysis of Anthropic's published data. Community validation: a developer loaded ~733K tokens (4 Harry Potter books) and Opus 4.6 retrieved 49/50 documented spells in a single prompt ([HN, Feb 2026](https://news.ycombinator.com/item?id=46905735)). Sonnet 4.6 MRCR scores not yet published.
The benchmark is the "8-needle 1M variant" — finding 8 specific facts in a 1M-token document. Opus 4.6 drops from 93% to 76% when scaling from 256K to 1M; Sonnet 4.5 collapses to 18.5%. **Community validation**: a developer loaded ~733K tokens (4 Harry Potter books) and Opus 4.6 retrieved 49/50 documented spells in a single prompt ([HN, Feb 2026](https://news.ycombinator.com/item?id=46905735)). Sonnet 4.6 MRCR not yet published, but community reports suggest it "struggles with following specific instructions and retrieving precise information" at full 1M context.
**Cost per session (approximate)**
Important: above 200K input tokens, **all** tokens in the request are charged at premium rates (not just the excess). Applies to both Sonnet 4.6 and Opus 4.6.
Above 200K input tokens, **all tokens** in the request are charged at premium rates — not just the excess. Applies to both Sonnet 4.6 and Opus 4.6.
| Session type | ~Tokens in | ~Tokens out | Sonnet 4.6 | Opus 4.6 |
|---|---|---|---|---|
@ -1775,13 +1775,17 @@ Important: above 200K input tokens, **all** tokens in the request are charged at
| Module refactoring (≤200K) | 150K | 20K | ~$0.75 | ~$1.25 |
| Full service analysis (>200K, 1M beta) | 500K | 50K | ~$4.13 | ~$6.88 |
For comparison: Gemini 1.5 Pro offers a 2M context window at $3.50/$10.50/MTok — significantly cheaper for pure long-context RAG. Community advice: use Gemini for large-document RAG, Claude for reasoning quality and agentic workflows.
**When to use which**
| Scenario | Recommendation |
|----------|---------------|
| Bug fix, PR review, daily coding | Sonnet 4.6 @ 200K — fast and cheap |
| Cross-module refactoring, large codebase | Sonnet 4.6 @ 1M — but premium pricing kicks in above 200K |
| Architecture analysis, Agent Teams, complex reasoning | Opus 4.6 @ 1M — stronger retrieval accuracy |
| Full-repo audit, entire codebase load | Opus 4.6 @ 1M — worth the cost for precision |
| Cross-module refactoring | Sonnet 4.6 @ 1M — but weigh cost vs. chunking + RAG |
| Architecture analysis, Agent Teams | Opus 4.6 @ 1M — strongest retrieval at scale |
| Large-document RAG (PDFs, legal, books) | Consider Gemini 1.5 Pro — cheaper at this scale |
**Key facts**
- Opus 4.6 max output: **128K tokens**; Sonnet 4.6 max output: **64K tokens**
@ -1789,6 +1793,8 @@ Important: above 200K input tokens, **all** tokens in the request are charged at
- 1M context is **beta** — requires `anthropic-beta: context-1m-2025-08-07` header, usage tier 4 or custom rate limits
- Above 200K input tokens: Sonnet 4.6 doubles to $6/$22.50/MTok; Opus 4.6 doubles to $10/$37.50/MTok
- If input stays ≤200K, standard pricing applies even with the beta flag enabled
- **Practical workaround**: check context at ~70% and open a new session rather than hitting compaction ([HN pattern](https://news.ycombinator.com/item?id=46902427))
- Community consensus: 200K + RAG is the default; 1M Opus is reserved for cases where loading everything at once is genuinely necessary
#### What Costs the Most?