[BUG] opusplan setting doesn't switch to Opus during plan mode

Found 2 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/16183
2. https://github.com/anthropics/claude-code/issues/13242

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Hi, trying to test out opusplan and have the same issue, only switching manually works, i switched to opusplan by doing /model opusplan and it "adds" the opusplan as a separate model.

Maybe I've missed an update or a doc entry, but this seems so contrived, why not just add an option so we can tell it what to use in plan mode and what to use in execution. I guess sub agents might be able to do the trick but it feels like a workaround for something that should have been simple.

And it doesn't help that they have a section for "opusplan" in their docs which implies it should be operational.

Any updates please?

yep, same experience here

I use Claude Max subscription.

If I set a model as /model opusplan in Claude Code (2.1.45) and switch to Plan mode then I see latest Opus in a /context output, If I switch back from Plan mode then I see latest Sonnet.

If you set a Haiku model as default, then Sonnet will be active in Plan mode.

It should work in the same way for AWS.

Docs: https://code.claude.com/docs/en/model-config

I can reproduce the issue.

I use bedrock, have configured ANTHROPIC_DEFAULT_OPUS_MODEL, ANTHROPIC_DEFAULT_SONNET_MODEL, ANTHROPIC_DEFAULT_HAIKU_MODEL, use { "model": "opusplan" } in my ~/.claude/settings.json.

I use plan mode extensively, but when I look at my aws cost explorer I was never charged for opus.

<img width="247" height="203" alt="Image" src="https://github.com/user-attachments/assets/2ef2e3e4-bec3-4fdf-b265-60c7c5575087" />

<img width="810" height="325" alt="Image" src="https://github.com/user-attachments/assets/a7aee315-09f9-46cc-9d64-33dd24025933" />

Same issue here on v2.1.61 (Linux, API direct — not Bedrock/Vertex).

/model opusplan resolves to claude-sonnet-4-6 in both plan mode and execution mode. The system prompt confirms: "You are powered by the model named Sonnet 4.6. The exact model ID is claude-sonnet-4-6" — even while actively in plan mode.

Expected: Opus 4.6 in plan mode, Sonnet 4.6 in execution mode.

Same here on v..2.1.68, but it's been the case of the past few months. We use bedrock.

Confirming this bug in non-interactive (-p) mode with Claude Code v2.1.86

Adding data from an automated CI/CD use case (hive-mind issue solver). We pass --model opusplan with the -p flag for headless operation, and the bug manifests there as well.

Our configuration

# Command sent to Claude CLI
claude --output-format stream-json --verbose --dangerously-skip-permissions --model opusplan -p "..."

Environment variables set:

• ANTHROPIC_DEFAULT_OPUS_MODEL=claude-opus-4-6
• ANTHROPIC_DEFAULT_SONNET_MODEL=claude-sonnet-4-6

What happened

The init event reported:

{ "model": "claude-sonnet-4-6" }

All API calls throughout the session used claude-sonnet-4-6 (main) and claude-haiku-4-5-20251001 (sub-agents). Zero Opus API calls in the entire session despite opusplan being requested.

Full log evidence

Full session log (gist) — search for model: to see all API requests going to sonnet/haiku, never opus.

Key lines from the log

| Line | Content |
|------|---------|
| 214 | claude --model opusplan -p "..." (correct command) |
| 452 | ANTHROPIC_DEFAULT_OPUS_MODEL=claude-opus-4-6 (env var set correctly) |
| 502 | "model": "claude-sonnet-4-6" (init event — wrong model!) |
| 555 | model: 'claude-sonnet-4-6' (first API call — sonnet, not opus) |

Environment

• Claude Code version: 2.1.86
• Platform: Linux (Docker, headless)
• API: Direct Anthropic API (not Bedrock/Vertex)
• Mode: Non-interactive (-p flag)

This confirms the bug is not Bedrock-specific — it reproduces with the direct Anthropic API in non-interactive mode as well.

@Felix-M-27 check with a /context command

@Felix-M-27 in general your report looks like as expected, the most reliable option here to figure out actual model in use is the /context.

the opusplan is just an alias, main model is supposed to be the sonnet.

I observed this:
opusplan only works when manually setting opus and sonnet like so:

ANTHROPIC_DEFAULT_SONNET_MODEL=us.anthropic.claude-sonnet-4-6 ANTHROPIC_DEFAULT_OPUS_MODEL=us.anthropic.claude-opus-4-6-v1[1m] claude

Now the interesting and inconsistent part:
running a command like this:
/plan my plan will get routed to sonnet at first, but if you run /plan and then type the plan, it will get routed to Opus correctly.

We are using bedrock as well.

    "CLAUDE_CODE_USE_BEDROCK": "1",
    "CLAUDE_CODE_SKIP_BEDROCK_AUTH": "1",
    "ANTHROPIC_AUTH_TOKEN": "sk-REDACTED",
    "ANTHROPIC_BEDROCK_BASE_URL": "https://REDACTED/bedrock",
    "ANTHROPIC_MODEL": "us.anthropic.claude-opus-4-6-v1[1m]"