[FEATURE]: Add support for Anthropic's Advisor Tool (Beta)

[baob]

• I have verified this feature I'm about to request hasn't been suggested before.

Note: Issue #21789 covered this feature but was auto-closed by the compliance bot for formatting issues before any maintainer could review the actual feature request on its merits. This is a properly formatted resubmission to ensure the feature gets human consideration.

Problem:

When working on complex coding tasks in OpenCode, I often need Opus-level intelligence for planning and decision-making, but running Opus for the entire conversation is expensive. Anthropic recently released an "Advisor Tool" that solves this perfectly - it lets Sonnet consult Opus mid-conversation for strategic guidance, giving near-Opus quality at mostly-Sonnet cost.

What I want:

I'd like OpenCode to support Anthropic's Advisor Tool so I can:

• Use Sonnet as my main model (keeps costs down, maintains access to all tools/files)
• Have Sonnet automatically consult Opus when it needs strategic guidance
• Get better results on complex tasks without paying for full Opus usage

How it works:

The advisor tool is a server-side Anthropic feature (similar to their bash or web_search tools). When enabled, Sonnet can call an "advisor" during generation. Anthropic routes that to Opus, gets advice, and Sonnet continues - all in one API request.

What needs to change:

1. Add the beta header: anthropic-beta: advisor-tool-2026-03-01
2. Support the advisor_20260301 tool type in the Anthropic provider
3. Let users configure it in opencode.json:

{
  "model": "anthropic/claude-sonnet-4-6",
  "advisor": {
    "enabled": true,
    "model": "anthropic/claude-opus-4-6"
  }
}

Why this matters to me:

I built a workaround script that uses the advisor tool externally, but it runs outside OpenCode's context so the advisor can't see my codebase. Native support would let me get Opus-level guidance while keeping full access to my project files.

Reference:
https://platform.claude.com/docs/en/agents-and-tools/tool-use/advisor-tool

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• Feature requests must have a title starting with [FEATURE]: (current title: "Add support for Anthropic's Advisor Tool (Beta)")
• The issue does not include the required verification checkbox from the Feature Request template

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be a duplicate of existing issues. Please check:

• Feature Request: Support Anthropic Advisor Strategy (advisor_20260301) #21789: Feature Request: Support Anthropic Advisor Strategy (advisor_20260301) — covers the same advisor_20260301 tool type, beta header, and configuration support (currently closed)

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

Thank you for updating the issue title to include [FEATURE]:! However, this issue is still missing a required field from the Feature Request template.

What still needs to be fixed:

• The required verification checkbox is missing: "I have verified this feature I'm about to request hasn't been suggested before."

Please edit the issue body to include this checkbox (checked), for example:

- [x] I have verified this feature I'm about to request hasn't been suggested before.

Please address this to bring the issue into compliance.

[github-actions]

Thank you for updating the issue title! However, this issue is still missing one required field from the Feature Request template.

What still needs to be fixed:

• The required verification checkbox is missing: "I have verified this feature I'm about to request hasn't been suggested before."

Please edit the issue body to include this checkbox (checked):

- [x] I have verified this feature I'm about to request hasn't been suggested before.

Please address this to bring the issue into compliance.

[baob]

Closing as duplicate of #21789.

I'd like to ask the maintainers to reconsider this feature request. While #21789 was auto-closed by the bot for not following the template format, the underlying feature request is valuable.

My use case: I'm working on complex coding tasks where I need Opus-level intelligence for strategic planning, but Opus is too expensive to run for entire conversations. Anthropic's Advisor Tool (released April 9, 2026) solves this perfectly - it lets Sonnet consult Opus mid-generation for guidance, giving near-Opus quality at mostly-Sonnet cost.

I built a workaround script that uses the advisor tool externally, but it runs outside OpenCode's context so the advisor can't see my codebase. Native support would allow Opus to provide strategic guidance while still having full access to project files and OpenCode's tools.

Could the team please share why this was marked "not planned"? Is there a technical limitation, or is this feature not aligned with OpenCode's roadmap?

Reference: https://platform.claude.com/docs/en/agents-and-tools/tool-use/advisor-tool

[github-actions]

Thanks for updating the issue! It now follows the contributing guidelines and feature request template. We appreciate the effort to resubmit this properly.