Claude Opus 4.6 in OpenClaw: Long-Context Setup Guide for March 2026

1. authenticate Anthropic in OpenClaw,
2. set anthropic/claude-opus-4-6 as the default model,
3. enable context1m only if your Anthropic credential actually has long-context access,
4. validate from openclaw models status and the dashboard, not from undocumented one-off chat commands.

That sounds simple, but the details matter because older draft guides often mix launch-day claims, gateway-specific behavior, and unsupported OpenClaw commands into one article.

TL;DR

• Anthropic announced Claude Opus 4.6 on February 5, 2026.
• Anthropic's launch post says Opus 4.6 adds adaptive thinking, effort controls, context compaction, 1M context in beta, and 128K max output.
• OpenClaw's Anthropic provider docs currently support anthropic/claude-opus-4-6 and say Claude 4.6 defaults to adaptive thinking when you do not set a level explicitly.
• OpenClaw's docs also make the 1M context path explicit: use params.context1m: true, and expect a 429 if your credential does not have long-context access.
• Anthropic's current pricing page now says Opus 4.6 includes the full 1M context window at standard pricing. That is more current than the launch-announcement wording, so use the live pricing page when publishing.

What is clearly documented right now

Why Opus 4.6 is relevant for OpenClaw users

Anthropic's announcement positions Opus 4.6 as better at:

• sustained agentic tasks
• large codebases
• code review and debugging
• deeper reasoning with adaptive thinking

The clean setup path in OpenClaw

OpenClaw's docs currently recommend the onboarding wizard rather than hand-editing everything first:

openclaw onboard
# choose: Anthropic API key

openclaw models list
openclaw models set anthropic/claude-opus-4-6
openclaw models status
openclaw dashboard

If you already know you want direct Anthropic API auth, OpenClaw also documents the non-interactive setup path:

openclaw onboard --anthropic-api-key "$ANTHROPIC_API_KEY"

This is the recommended default for shared or production-style gateway hosts. OpenClaw also supports Anthropic setup-tokens and a Claude CLI backend, but those are different operational paths with different limits.

Minimal config for long-context work

This is the smallest useful config shape if you want Opus 4.6 as the default model and want OpenClaw to request the 1M beta path where available:

{
  env: { ANTHROPIC_API_KEY: "sk-ant-..." },
  agents: {
    defaults: {
      model: { primary: "anthropic/claude-opus-4-6" },
      models: {
        "anthropic/claude-opus-4-6": {
          params: {
            context1m: true,
            cacheRetention: "long"
          }
        }
      }
    }
  }
}

Two important caveats:

• context1m: true is not just a preference toggle. OpenClaw's docs say this adds the Anthropic beta header for 1M context requests.
• If your credential is not allowed to use long context, Anthropic may return HTTP 429: rate_limit_error: Extra usage is required for long context requests.

Adaptive thinking is already the default

This is one of the biggest fixes from the original draft.

You still have two ways to take control when needed:

• per message: /think:<level>
• per model config: agents.defaults.models["anthropic/<model>"].params.thinking

The practical recommendation is:

Pricing: use the current pricing page, not the launch-day memory

This is where older articles tend to drift.

• Claude Opus 4.6 includes the full 1M context window at standard pricing
• standard price is $5 / MTok input and $25 / MTok output
• Batch API pricing is $2.50 / MTok input and $12.50 / MTok output
• fast mode is $30 / MTok input and $150 / MTok output

When Opus 4.6 is worth the cost

Use Opus 4.6 when the value comes from avoiding failure or avoiding repeated retries:

• large-repo architectural review
• multi-file debugging that depends on long context
• long document synthesis with many dependencies
• quality-first agent sessions that are expensive to rerun

Use Sonnet or another cheaper default when the work is repetitive, shallow, or latency-sensitive.

That is why the better production pattern is usually:

• default to a cheaper model for broad traffic
• escalate to Opus 4.6 for the hard slice of work

Simpler alternative: use Claude Opus 4.6 through EvoLink

If you do not need OpenClaw's session management layer, the fastest way to access Claude Opus 4.6 is through EvoLink's OpenAI-compatible gateway. No provider-specific wiring required:

from openai import OpenAI

client = OpenAI(
    base_url="https://api.evolink.ai/v1",
    api_key="YOUR_EVOLINK_API_KEY",
)

response = client.chat.completions.create(
    model="claude-opus-4-6",
    messages=[{"role": "user", "content": "Review this architecture for scalability risks."}],
    max_tokens=64000,
)

EvoLink handles Anthropic auth, routing, retry, and failover behind a single API key. You get the same Opus 4.6 model with adaptive thinking enabled by default — no extra config needed.

For most production API workflows, EvoLink is the simpler path. Use OpenClaw when you need its session orchestration features.

Validation checklist

What about Claude CLI instead of Anthropic API?

OpenClaw supports a Claude CLI backend too, but the docs are clear about the tradeoff:

• it is best for a single-user gateway host
• it is not the same as the Anthropic API provider
• OpenClaw-side tools are disabled for CLI backend runs
• it is text-in, text-out rather than a general API-key production path

So for a shared gateway or production API workflow, direct Anthropic API auth is still the cleaner recommendation.

FAQ

Can I use Claude Opus 4.6 through EvoLink instead of OpenClaw?

Does OpenClaw officially support Claude Opus 4.6?

Do I need to manually enable thinking in OpenClaw?

Is 1M context available everywhere?

Why would a long-context request fail with a 429?

Because Anthropic may reject 1M-context requests when the credential does not have long-context access or extra-usage eligibility. OpenClaw documents that exact failure mode.

Should I use fast mode by default?

No. Fast mode is a premium path at 6x standard Opus 4.6 pricing. Use it only when lower latency is worth the cost and you are on direct Anthropic API-key traffic.

Is the launch-announcement pricing still the source of truth?

No. Use Anthropic's live pricing page. As of March 29, 2026, it is more current and says Opus 4.6 includes full 1M context at standard pricing.

What is the safest way to verify the setup?

Try Claude Opus 4.6 Through EvoLink

If you want Opus 4.6 available alongside other model families without maintaining separate provider wiring, EvoLink gives you a single API key that routes to Anthropic, OpenAI, Google, and more. Start with EvoLink for the simplest setup, or pair it with OpenClaw if you need session orchestration.

Sources

• Anthropic Opus 4.6 announcement
• Anthropic pricing docs
• OpenClaw Anthropic provider docs
• OpenClaw models CLI docs
• OpenClaw dashboard docs