OpenCode error
OpenCode: AI_APICallError ... tool_use ids were found without tool_result blocks
AI_APICallError: messages.13: `tool_use` ids were found without `tool_result` blocks immediately after: toolu_01CfJCsh21fK1pAXsXWYJYBA, toolu_01NoqnwsaxoK3AYM2FyrxmjN. Each `tool_use` block must have a corresponding `tool_result` block in the next message.Status: Fixed in releaseLast verified 2 documented fixes4 sources
What it means
The session history sent to an Anthropic model contains a tool call with no matching tool result, so the API rejects every later request in that session.
Causes
- A maintainer asked whether it happened after an abort, meaning a request was aborted and the conversation then continued (#1662).
- A maintainer: "this is a bug with the anthropic api itself it sends back duplicate content or something and messes up the state of the client. We can fix it on our end its just a little messy reordering things all the time" (#1662).
How to fix it
- Fix 1.
Fixed by PR #22646 "fix: ensure tool_use is always followed by tool_result", merged 2026-04-15, which closed #1662. The next release after the merge was v1.4.7. Upgrade.
Terminalopencode upgrade - Fix 2.
An earlier related fix shipped in v1.0.164: "Fixed user invoked subtasks that were causing tool_use or missing thinking signatures".
More OpenCode errors
All 17 OpenCode errorsProviderModelNotFoundErrorStatus: By designProviderInitErrorStatus: WorkaroundAI_APICallErrorStatus: WorkaroundThis credential is only authorized for use with Claude Code and cannot be used for other API requests.Status: By designmessages.3.content.0.type: Expected `thinking` or `redacted_thinking`, but found `tool_use`. When `thinking` is enabled, a final `assistant` message must start with a thinking block (preceeding the lastmost set of `tool_use` and `tool_result` blocks). We recommend you include thinking blocks from previous turns. To avoid this requirement, disable `thinking`.Status: WorkaroundError: Unexpected error, check log file at [user-home]/.local/share/opencode/log/2025-08-26T215857.log for more detailsStatus: WorkaroundAI_RetryError: Failed after 4 attempts. Last error: Too Many RequestsStatus: Workaroundundefined: The provided model identifier is invalid.Status: Fixed in release
Related reading
- OpenCode Hacked: What the Console Breach Means for Your API KeysOpenCode disclosed a breach of its Console that may have exposed provider keys. Who is affected, what to rotate today, and why hosted key gateways are the real risk.
- OpenCode 2: How to Upgrade From v1 Without Breaking Your SetupOpenCode 2 upgrade from v1: what the migration guide says breaks (plugins, server API, TUI config), what carries over, and a safe checklist before you switch.
- Run Your Coding Agent as an API: OpenCode Server on RailwayOpenCode server on Railway: run opencode serve in a container as a password-protected HTTP API with a persistent volume, reachable from any machine or webhook.
- Give Every Agent PR a Live Preview: Railway Environments for AI Pull RequestsRailway preview environments for agent pull requests: an isolated copy of your whole stack for every PR, so you verify agent changes by running them.
- GPT-6 Astra Release Guide: Benchmarks, $10/$50 Pricing, and How to Run It in Codex and OpenCodeGPT-6 Astra release guide: OpenAI's max-capability model, its $10/$50 pricing and 1.05M context, what the benchmarks do and do not say, and commands to try it.
- Put an AI Reviewer on Every Pull Request: A Webhook Build with OpenCode and RailwayBuild an AI pull request reviewer on Railway: a webhook service runs OpenCode headless on every PR diff and posts findings as a review, never touching the code.
FAQ
What does "AI_APICallError ... tool_use ids were found without tool_result blocks" mean in OpenCode?
The session history sent to an Anthropic model contains a tool call with no matching tool result, so the API rejects every later request in that session.
How do I fix "AI_APICallError ... tool_use ids were found without tool_result blocks"?
There are 2 documented fixes. Start with the first: Fixed by PR #22646 "fix: ensure tool_use is always followed by tool_result", merged 2026-04-15, which closed #1662. The next release after the merge was v1.4.7. Upgrade.
Is this OpenCode error fixed?
Status: Fixed in release. A release fixed this. The affected versions note says where the fix landed. Affected versions: Reported from v0.5.x through early 2026 (also on 1.0.157). Fixed by PR #22646 (merged 2026-04-15).
Sources
Last verified against 4 sources: official docs, maintainer replies and release notes.
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