The open-source coding environment OpenCode removed all Anthropic and Claude AI references from its codebase on March 19, 2026, following a legal request from Anthropic. The changes were merged in pull request #18186 on the anomalyco/opencode GitHub repository by maintainer thdxr, whose full name was not available at time of publication.
- OpenCode maintainer thdxr merged PR #18186 on March 19, 2026, removing all Anthropic and Claude references from the codebase after a legal request from Anthropic.
- Four components were removed: the
anthropic-20250930.txtprompt file, theopencode-anthropic-authbuilt-in plugin, Anthropic from provider hints, and Anthropic from the provider enum. - The GitHub community expressed strong disapproval, with 508 thumbs-down reactions against 18 thumbs-up reactions on the pull request.
- An automated code review by Greptile identified a regression that silently drops the User-Agent header for third-party providers including OpenAI, Google, and Azure.
What Happened
On March 19, 2026, OpenCode — an open-source AI-assisted development environment maintained under the GitHub organization anomalyco — merged a pull request removing all references to Anthropic and its Claude AI models from the codebase. The pull request was filed by maintainer thdxr, whose description stated its purpose directly: “Remove anthropic references per legal requests.” The merge incorporated two commits into the project’s active development branch and was completed the same day it was opened.
OpenCode holds approximately 135,000 GitHub stars and 14,600 forks, placing it among the more widely used open-source AI-assisted coding tools. The repository remains public and active; only the Anthropic-specific components were removed.
Why It Matters
Anthropic’s Claude models had been natively integrated into OpenCode, allowing developers to authenticate and invoke Claude directly within the tool through a dedicated built-in plugin. That integration — along with the associated system prompt configuration, beta header flags, and provider selection options — has been fully removed from the codebase.
The case represents a publicly documented instance of an AI model provider issuing legal requests to control how its brand and authentication infrastructure are embedded in third-party open-source software. Anthropic has not issued a public statement explaining the specific legal grounds for the request, whether related to trademark policy, API terms of service, or other provisions.
Technical Details
The pull request specified four discrete removals: the anthropic-20250930.txt system prompt file was deleted from the repository; the opencode-anthropic-auth built-in authentication plugin, which handled Anthropic OAuth and Pro-Max subscription login flows, was removed entirely; Anthropic was stripped from the tool’s provider hints configuration; and Anthropic was removed from the provider enum governing the user-facing provider selection interface.
According to an automated code analysis by Greptile, the changes also eliminated a claude-code-20250219 beta header flag that had been included in requests to the Anthropic API. The Greptile review further flagged an unintended regression: the modifications silently drop the User-Agent: opencode/${VERSION} header that had previously been sent on all requests to non-OpenCode, non-Anthropic providers — including OpenAI, Google, and Azure. This means those external providers can no longer identify the version of OpenCode initiating the request.
The same automated review noted documentation inconsistencies introduced by the removal and flagged them as requiring additional fixes before the Anthropic references could be considered fully excised from the project.
Who’s Affected
Developers who relied on OpenCode’s native Claude integration — particularly those using Anthropic’s OAuth-based Pro and Max subscription tiers for authentication — will need to reconfigure their setup or migrate to another supported provider within the tool. The opencode-anthropic-auth plugin that managed that authentication pathway no longer exists in the codebase.
The User-Agent regression introduced by the changes also creates unintended consequences for users of other providers. OpenAI, Google, and Azure integrations within OpenCode will no longer transmit the tool’s version identifier in request headers until the regression is corrected in a follow-up commit.
What’s Next
As of the merge date of March 19, 2026, the documentation inconsistencies identified by Greptile’s automated review remained unresolved. No public follow-up pull request addressing those gaps or the User-Agent header regression was visible in the repository at time of publication.
Community reaction to the pull request was heavily negative: the merge drew 508 thumbs-down reactions against 18 thumbs-up reactions, along with 164 confusion-emoji responses and 33 laughter-emoji responses recorded on the pull request page. Anthropic has not publicly disclosed the legal basis for its request, and OpenCode has not indicated whether alternative approaches to Claude model access — such as user-supplied API keys without branded authentication plugins — are under consideration for future releases.
