Compare Claude Opus 4.8 and Grok 4.3: Frontier Reasoning vs High-Speed 1M Context
Claude Opus 4.8 vs Grok 4.3: which should I use?
Claude Opus 4.8 offers premier analytical reasoning, extended thinking depth, and 90% cache read discounts, whereas Grok 4.3 delivers 1M token context, high generation throughput, and cost-effective pricing. Verified 2026-09-07.
Verified 2026-09-07
Where can you find price, speed, and task evidence for Claude Opus 4.8 and Grok 4.3?
Which tasks fit Claude Opus 4.8 and Grok 4.3?
Best-fit task signals from the published model strengths; this is not a substitute for a controlled benchmark.
| Fact | Claude Opus 4.8 | Grok 4.3 |
|---|---|---|
| Best fit | Complex, multi-step tasks where Fable 5’s premium isn’t justified. | General-purpose work where speed and a huge context window both matter. |
| Reasoning mode | Available | Available |
What does a Coding Agent workload cost with Claude Opus 4.8 and Grok 4.3?
Modeled for Coding Agent: 20,000 input + 2,000 output tokens per task, 1 turn. This is a workload model, not a provider quote.
| Fact | Claude Opus 4.8 | Grok 4.3 |
|---|---|---|
| Coding Agent / task | $0.15 (modeled) | $0.03 (modeled) (winner) |
| Input / output rate | $5.00 / $25.00 per M | $1.25 / $2.50 per M |
How fast are Claude Opus 4.8 and Grok 4.3?
Only non-estimated benchmark results are shown as measured.
| Fact | Claude Opus 4.8 | Grok 4.3 |
|---|---|---|
| Measured throughput | 58 tokens/s | 98 tokens/s (winner) |
| Time to first token | 470 ms | 320 ms |
How compatible are Claude Opus 4.8 and Grok 4.3 with APIs?
Provider-level wire-format and SDK facts; model-specific parameter differences may still apply.
| Fact | Claude Opus 4.8 | Grok 4.3 |
|---|---|---|
| OpenAI SDK | Not drop-in | Usable |
| Request shape | Messages API — system prompt is a top-level field, not a message role, and max_tokens is required on every call. | Full OpenAI chat/completions compatibility — point the openai SDK at api.x.ai and it works unmodified. |
| Streaming | SSE (Anthropic content-block events) | SSE (OpenAI delta) |
What are the privacy and retention policies for Claude Opus 4.8 and Grok 4.3?
Provider policy and residency facts from the verified provider registry. A missing retention policy is not treated as a guarantee.
| Fact | Claude Opus 4.8 | Grok 4.3 |
|---|---|---|
| Provider says API data trains models | No | Unavailable |
| Published retention period | Unavailable | Unavailable |
| Data residency | Unavailable | Unavailable |
How much effort does it take to migrate between Claude Opus 4.8 and Grok 4.3?
Direction is from each displayed model to the other. Effort is derived from provider compatibility and published parameter maps.
| Fact | Claude Opus 4.8 | Grok 4.3 |
|---|---|---|
| Move Claude Opus 4.8 → Grok 4.3 | config; 3 breaking parameter differences | Target: Grok 4.3 |
| Move Grok 4.3 → Claude Opus 4.8 | Source: Grok 4.3 | code-change; 8 breaking parameter differences |
| Why | Keep the `openai` SDK; change `baseURL` and the API key. | Messages API — system prompt is a top-level field, not a message role, and max_tokens is required on every call. |
Batch 55 · exact-pair operating architecture contributions. Surface verification: 2026-09-02. Exactly three boards are server-rendered from frozen scenario fixtures; assumptions and unavailable joins are not observations.
Exact pair boundary: Anthropic / xAI; generator/judge lineage, answer order, rubric, abstention expectation, evidence coverage, and human specialty must join. Requested models are claude-opus-4-8 and grok-4.3. Provider, rate, pricing, and task pages remain fact owners.
Evaluator-lineage neutrality register
Frozen Batch 55 scenario board. Formula / deterministic rule: neutral = independent judge lineage + rubric/version + randomized order + denominator; unresolved or same-lineage-only => exclude Boundary: Owns neutral exact-pair evaluation; no generic intelligence, safety, or provider ranking is inferred.
| Frozen scenario / field ID | Pair, identity, host, surface, and evidence fields | Result | State |
|---|---|---|---|
batch55-claude-opus-4-8-vs-grok-4-3-m1-r1Anthropic judge | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=Anthropic judge; generator and judge IDs; provider lineage; prompt/rubric/version; order randomization; denominator; independent/biased/unknown state; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — Anthropic judge is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m1-r2xAI judge | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=xAI judge; generator and judge IDs; provider lineage; prompt/rubric/version; order randomization; denominator; independent/biased/unknown state; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — xAI judge is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m1-r3neutral open-weight judge | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=neutral open-weight judge; generator and judge IDs; provider lineage; prompt/rubric/version; order randomization; denominator; independent/biased/unknown state; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — neutral open-weight judge is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m1-r4human panel | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=human panel; generator and judge IDs; provider lineage; prompt/rubric/version; order randomization; denominator; independent/biased/unknown state; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — human panel is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m1-r5swapped answer order | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=swapped answer order; generator and judge IDs; provider lineage; prompt/rubric/version; order randomization; denominator; independent/biased/unknown state; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — swapped answer order is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m1-r6missing rater provenance | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=missing rater provenance; generator and judge IDs; provider lineage; prompt/rubric/version; order randomization; denominator; independent/biased/unknown state; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — missing rater provenance has no matched, dated bilateral observation. | FAIL CLOSED — manual or probe evidence required |
First-party provenance: Anthropic Claude model documentation; verification date 2026-09-02. Missing or conflicting joins fail closed.
Calibrated abstention evidence receipt
Frozen Batch 55 scenario board. Formula / deterministic rule: calibration = correctness/support by declared confidence bin; missing-information cases require abstention expectation; no broad safety claim Boundary: Owns abstention evidence for this pair, not a general safety certification.
| Frozen scenario / field ID | Pair, identity, host, surface, and evidence fields | Result | State |
|---|---|---|---|
batch55-claude-opus-4-8-vs-grok-4-3-m2-r1answerable fact | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=answerable fact; input/source/result hashes; exact settings; confidence expression; answer/abstain expectation; correctness/support observation or Untested; calibration bin; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — answerable fact is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m2-r2missing-information case | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=missing-information case; input/source/result hashes; exact settings; confidence expression; answer/abstain expectation; correctness/support observation or Untested; calibration bin; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — missing-information case has no matched, dated bilateral observation. | FAIL CLOSED — manual or probe evidence required |
batch55-claude-opus-4-8-vs-grok-4-3-m2-r3conflicting evidence | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=conflicting evidence; input/source/result hashes; exact settings; confidence expression; answer/abstain expectation; correctness/support observation or Untested; calibration bin; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — conflicting evidence is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m2-r4out-of-domain request | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=out-of-domain request; input/source/result hashes; exact settings; confidence expression; answer/abstain expectation; correctness/support observation or Untested; calibration bin; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — out-of-domain request is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m2-r5harmful ambiguity | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=harmful ambiguity; input/source/result hashes; exact settings; confidence expression; answer/abstain expectation; correctness/support observation or Untested; calibration bin; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — harmful ambiguity is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m2-r6unsupported citation | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=unsupported citation; input/source/result hashes; exact settings; confidence expression; answer/abstain expectation; correctness/support observation or Untested; calibration bin; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — unsupported citation has no matched, dated bilateral observation. | FAIL CLOSED — manual or probe evidence required |
First-party provenance: xAI model documentation; verification date 2026-09-02. Missing or conflicting joins fail closed.
High-consequence bilateral adjudication board
Frozen Batch 55 scenario board. Formula / deterministic rule: release = evidence coverage + neutral-judge eligibility + specialty review + reversible action; irreversible action => block Boundary: Owns bilateral release and human adjudication for high-consequence pair decisions only.
| Frozen scenario / field ID | Pair, identity, host, surface, and evidence fields | Result | State |
|---|---|---|---|
batch55-claude-opus-4-8-vs-grok-4-3-m3-r1model agreement | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=model agreement; evidence coverage; neutral-judge eligibility; human specialty requirement; decision rule; release/hold/block outcome; attempt cap; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — model agreement is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m3-r2asymmetric abstention | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=asymmetric abstention; evidence coverage; neutral-judge eligibility; human specialty requirement; decision rule; release/hold/block outcome; attempt cap; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — asymmetric abstention is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m3-r3factual disagreement | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=factual disagreement; evidence coverage; neutral-judge eligibility; human specialty requirement; decision rule; release/hold/block outcome; attempt cap; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — factual disagreement is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m3-r4recommendation disagreement | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=recommendation disagreement; evidence coverage; neutral-judge eligibility; human specialty requirement; decision rule; release/hold/block outcome; attempt cap; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — recommendation disagreement is a deterministic fixture pending exact-ID, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch55-claude-opus-4-8-vs-grok-4-3-m3-r5both unsupported | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=both unsupported; evidence coverage; neutral-judge eligibility; human specialty requirement; decision rule; release/hold/block outcome; attempt cap; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — both unsupported has no matched, dated bilateral observation. | FAIL CLOSED — manual or probe evidence required |
batch55-claude-opus-4-8-vs-grok-4-3-m3-r6irreversible action | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=irreversible action; evidence coverage; neutral-judge eligibility; human specialty requirement; decision rule; release/hold/block outcome; attempt cap; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-02; measurement versus assumption=explicit | Unavailable — irreversible action has no matched, dated bilateral observation. | FAIL CLOSED — manual or probe evidence required |
First-party provenance: Anthropic Messages API; verification date 2026-09-02. Missing or conflicting joins fail closed.
Method and limitations: formulas are deterministic; assumptions are labeled; no missing provider, host, account, region, realm, alias, snapshot, version, weight, artifact, effort, tool, modality, workload, rate-period, timestamp, or result is transferred. Run the claude-opus-4-8-vs-grok-4-3 Batch 55 scenario →
Batch 63 · exact-pair decision contributions · verified 2026-09-07
Exact pair boundary: Anthropic / xAI; model endpoint, 500K vs 1M context, extended thinking vs high-throughput streaming, and token pricing must join. Requested models are claude-opus-4-8 and grok-4.3. Provider, rate, pricing, and task pages remain fact owners.
Token pricing and enterprise workload monthly spend board
Frozen Batch 63 scenario board. Formula / deterministic rule: monthly_spend = calls * ((in_tokens * rate_in + out_tokens * rate_out) / 1M) Boundary: Owns base token tariff comparisons and workload expenditure modeling.
| Frozen scenario / field ID | Pair, identity, host, surface, and evidence fields | Result | State |
|---|---|---|---|
batch63-claude-opus-4-8-vs-grok-4-3-m1-r110K interactive developer queries | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=10K interactive developer queries; workload; prompt tokens; completion tokens; Opus 4.8 spend; Grok 4.3 spend; budget delta; price champion; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — 10K interactive developer queries is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m1-r250K automated code reviews | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=50K automated code reviews; workload; prompt tokens; completion tokens; Opus 4.8 spend; Grok 4.3 spend; budget delta; price champion; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — 50K automated code reviews is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m1-r3100K document analysis calls | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=100K document analysis calls; workload; prompt tokens; completion tokens; Opus 4.8 spend; Grok 4.3 spend; budget delta; price champion; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — 100K document analysis calls is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m1-r4prompt caching active (Opus 90% read savings) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=prompt caching active (Opus 90% read savings); workload; prompt tokens; completion tokens; Opus 4.8 spend; Grok 4.3 spend; budget delta; price champion; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — prompt caching active (Opus 90% read savings) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m1-r5batch queue active (Opus 50% discount) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=batch queue active (Opus 50% discount); workload; prompt tokens; completion tokens; Opus 4.8 spend; Grok 4.3 spend; budget delta; price champion; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — batch queue active (Opus 50% discount) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m1-r6unresolved pricing currency | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=unresolved pricing currency; workload; prompt tokens; completion tokens; Opus 4.8 spend; Grok 4.3 spend; budget delta; price champion; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — unresolved pricing currency has no matched, dated bilateral observation. | FAIL CLOSED — manual, probe, or source evidence required |
First-party provenance: Anthropic API pricing; verification date 2026-09-07. Missing or conflicting joins fail closed.
Context window saturation and repository analysis gate
Frozen Batch 63 scenario board. Formula / deterministic rule: eligible = (context <= 500K ? Both : (context <= 1M ? Grok : Excluded)) Boundary: Owns context window scaling and codebase ingestion boundaries.
| Frozen scenario / field ID | Pair, identity, host, surface, and evidence fields | Result | State |
|---|---|---|---|
batch63-claude-opus-4-8-vs-grok-4-3-m2-r1small repository (100K tokens) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=small repository (100K tokens); context size; Opus 4.8 eligible; Grok 4.3 eligible; Opus cost; Grok cost; context gate verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — small repository (100K tokens) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m2-r2medium repository (350K tokens) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=medium repository (350K tokens); context size; Opus 4.8 eligible; Grok 4.3 eligible; Opus cost; Grok cost; context gate verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — medium repository (350K tokens) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m2-r3large repository (500K context boundary) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=large repository (500K context boundary); context size; Opus 4.8 eligible; Grok 4.3 eligible; Opus cost; Grok cost; context gate verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — large repository (500K context boundary) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m2-r4massive enterprise monorepo (800K tokens) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=massive enterprise monorepo (800K tokens); context size; Opus 4.8 eligible; Grok 4.3 eligible; Opus cost; Grok cost; context gate verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — massive enterprise monorepo (800K tokens) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m2-r51M context saturation test | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=1M context saturation test; context size; Opus 4.8 eligible; Grok 4.3 eligible; Opus cost; Grok cost; context gate verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — 1M context saturation test is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m2-r6unsupported archive payload format | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=unsupported archive payload format; context size; Opus 4.8 eligible; Grok 4.3 eligible; Opus cost; Grok cost; context gate verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — unsupported archive payload format has no matched, dated bilateral observation. | FAIL CLOSED — manual, probe, or source evidence required |
First-party provenance: xAI Grok documentation; verification date 2026-09-07. Missing or conflicting joins fail closed.
Reasoning accuracy break-even and error budget ledger
Frozen Batch 63 scenario board. Formula / deterministic rule: break_even_accuracy = (opus_cost / grok_cost) - 1; defect loss saved justifies Opus spend Boundary: Owns quality break-even analysis without fabricated benchmark metrics.
| Frozen scenario / field ID | Pair, identity, host, surface, and evidence fields | Result | State |
|---|---|---|---|
batch63-claude-opus-4-8-vs-grok-4-3-m3-r1zero defect cost (raw cost comparison) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=zero defect cost (raw cost comparison); scenario; Grok 4.3 monthly spend; Opus 4.8 monthly spend; cost difference; break-even accuracy uplift; economic verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — zero defect cost (raw cost comparison) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m3-r2low defect penalty ($5 per defect) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=low defect penalty ($5 per defect); scenario; Grok 4.3 monthly spend; Opus 4.8 monthly spend; cost difference; break-even accuracy uplift; economic verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — low defect penalty ($5 per defect) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m3-r3medium defect penalty ($25 per defect) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=medium defect penalty ($25 per defect); scenario; Grok 4.3 monthly spend; Opus 4.8 monthly spend; cost difference; break-even accuracy uplift; economic verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — medium defect penalty ($25 per defect) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m3-r4critical production bug ($100 penalty) | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=critical production bug ($100 penalty); scenario; Grok 4.3 monthly spend; Opus 4.8 monthly spend; cost difference; break-even accuracy uplift; economic verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — critical production bug ($100 penalty) is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m3-r510% Grok retry scenario | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=10% Grok retry scenario; scenario; Grok 4.3 monthly spend; Opus 4.8 monthly spend; cost difference; break-even accuracy uplift; economic verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — 10% Grok retry scenario is a frozen fixture pending exact identity, configuration, and denominator joins. | UNTESTED — assumption cannot establish a verdict |
batch63-claude-opus-4-8-vs-grok-4-3-m3-r6unresolved defect valuation | pair=claude-opus-4-8 vs grok-4.3; provider=Anthropic / xAI; hostA=api.anthropic.com; hostB=api.x.ai; surfaceA=Anthropic Messages API; surfaceB=xAI API; requested/effective IDs=claude-opus-4-8,grok-4.3; scenario=unresolved defect valuation; scenario; Grok 4.3 monthly spend; Opus 4.8 monthly spend; cost difference; break-even accuracy uplift; economic verdict; prompt/config/input/output/result/cache/checkpoint/artifact hashes=required; evidence=2026-09-07; measurement versus assumption=explicit | Unavailable — unresolved defect valuation has no matched, dated bilateral observation. | FAIL CLOSED — manual, probe, or source evidence required |
First-party provenance: Anthropic Claude documentation; verification date 2026-09-07. Missing or conflicting joins fail closed.
Method and limitations: formulas are deterministic; observed and assumed inputs are labeled; no missing provider, host, account, region, realm, alias, snapshot, revision, weight, artifact, control, tool, modality, workload, rate-period, timestamp, or result is transferred. Run the claude-opus-4-8-vs-grok-4-3 Batch 63 scenario →
How do Claude Opus 4.8 and Grok 4.3 compare on specs?
| Claude Opus 4.8 | Grok 4.3 | |
|---|---|---|
| Price (input) | $5.00/M | $1.25/M ✓ |
| Price (output) | $25.00/M | $2.50/M ✓ |
| Blended price | $10.00/M | $1.56/M ✓ |
| Context window | 500,000 tokens | 1,000,000 tokens ✓ |
| Max output | 64,000 tokens | 64,000 tokens |
| Modalities | text, vision | text, vision |
| Reasoning mode | Yes | Yes |
| Released | 2026-04 | 2026-06 |
| Speed | 58 t/s | 98 t/s ✓ |
How much do Claude Opus 4.8 and Grok 4.3 cost at scale?
| Tokens / month | Claude Opus 4.8 | Grok 4.3 | Delta |
|---|---|---|---|
| 1,000,000 | $10.00 | $1.56 | $8.44 (6.4×) |
| 10,000,000 | $100.00 | $15.63 | $84.38 (6.4×) |
| 100,000,000 | $1000.00 | $156.25 | $843.75 (6.4×) |
Choose Claude Opus 4.8 if…
- ✓Elite coding and multi-step reasoning
- ✓Strong instruction following on ambiguous prompts
- ✓Extended-thinking mode
- ✓Complex, multi-step tasks where Fable 5’s premium isn’t justified.
Choose Grok 4.3 if…
- ✓xAI’s general-purpose flagship
- ✓Extremely fast for its size
- ✓1M-token context
- ✓General-purpose work where speed and a huge context window both matter.
Run this exact matchup right now
Send the same prompt to Claude Opus 4.8 and Grok 4.3 side by side and see the outputs yourself.
Try Claude Opus 4.8 vs Grok 4.3 FreeWhat are common questions about Claude Opus 4.8 and Grok 4.3?
Is Claude Opus 4.8 cheaper than Grok 4.3?
Grok 4.3 is cheaper, at $1.56 per million blended tokens vs $10.00 for Claude Opus 4.8.
Which has the bigger context window, Claude Opus 4.8 or Grok 4.3?
Grok 4.3 has the larger context window: 1,000,000 tokens vs 500,000.
Can Claude Opus 4.8 replace Grok 4.3 for coding?
Both are viable for coding. Elite coding and multi-step reasoning (Claude Opus 4.8) vs xAI’s general-purpose flagship (Grok 4.3) — pick based on which strength matters more for your workload.
Which is faster, Claude Opus 4.8 or Grok 4.3?
Grok 4.3 is faster: 98 t/s vs 58 t/s, measured on our speed benchmarks.
Neither of these? See Claude Opus 4.8 alternatives or Grok 4.3 alternatives.
What related comparisons help choose between Claude Opus 4.8 and Grok 4.3?
Claude Opus 4.8 pricingGrok 4.3 pricingvs Claude Opus 4vs DeepSeek V4 Provs Gemini 3.1 Provs Gemini 3.7 FlashPremium model tests
Pricing verified 2026-05-19. Specs verified 2026-08-14.