Tool use id bug

Description

I uploaded 2 images and a short message, got hit with this error.

OpenCode version

1.0.167

Steps to reproduce

Upload 2 images with ctrl + v
Add a short message
Click enter

Screenshot and/or share link

Operating System

macOS 26.2

Terminal

Ghostty

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

AI_APICallError: tool_use blocks found without corresponding tool_result blocks #2720: AI_APICallError: tool_use blocks found without corresponding tool_result blocks
AI_APICallError: tool_use ids were found without tool_result blocks immediately after #1662: AI_APICallError: tool_use ids were found without tool_result blocks immediately after
AI_APICallError: messages.1.content.2: tool_use ids must be unique #1279: AI_APICallError: messages.1.content.2: tool_use ids must be unique
AI_APICallError: tool_use ids must be unique #1150: AI_APICallError: tool_use ids must be unique
In Memory Image can't be Pasted in Opencode After TUI Upgrade. #4077: In Memory Image can't be Pasted in Opencode After TUI Upgrade (image-related issues)
Switching from an image supported model to a non-image model breaks the thread #5101: Switching from an image supported model to a non-image model breaks the thread (image handling)

Feel free to ignore if none of these address your specific case.

ill look into it

How do I replicate?

I saw ur description but I think this prolly has to do w/ ordering and whatnot

If u could export session: opencode export > session.json it'd be amazing

https://gist.github.com/deriegle/db117ea51f6f55e814e855541bcd47ee

I ran into this too. I had a longer session and was on the main branch in my repo. I had a few files staged and ran /rmslop (same as in opencode) and ran into this bug. I opened a new session and ran /rmslop and got the error again. The gist above is from the second session.

EDIT: realizing the way mine happened was different (no images uploaded) but the error was similar in case that's helpful. Otherwise we can mark this as unrelated.

@deriegle

@deriegle can u give me the raw json export tho? opencode export > session.json

Sorry about that. I've added the session.json into this gist: https://gist.github.com/deriegle/db117ea51f6f55e814e855541bcd47ee

Several of the calls outputted my entire files since it was diffing them, I obfuscated the file names & outputs. If those end up being required to debug this, I can find another way to share that.

@rekram1-node

https://gist.github.com/Mishkun/02648359700010e559f7edf6bc8ac4dd

@rekram1-node I finally got this on a pet project, so I can share one in the full

I get this error many times so logged out and tried investigate with Opus. What I found.
(I posted this on other issue, but marked as off-topic - this issue is more related)

Tool Validation Error: Missing tool_result After Interruption

Root Cause

Client doesn't insert tool_result message after interruption before allowing model to continue.

When abort happens, client appends retry to the SAME assistant message instead of starting a new turn with tool_result in between.

Summary

Anthropic's Messages API rejects conversation history when an assistant message contains content (thinking/text) AFTER a tool_use block. The API expects tool_result immediately after tool_use, but when content appears in between, validation fails.

Error Message

messages.{N}: `tool_use` ids were found without `tool_result` blocks immediately after: {tool_id}. 
Each `tool_use` block must have a corresponding `tool_result` block in the next message.

The Rule

All tool_use blocks must be contiguous at the END of the assistant message content.

Once a tool_use block appears, only more tool_use blocks can follow. Any other content (thinking, text) AFTER a tool_use is invalid.

Valid vs Invalid Patterns

Valid: Tools grouped at end

assistant: [thinking, text, tool_use_A, tool_use_B]
user: [tool_result_A, tool_result_B]

Valid: Separate turns per tool

assistant: [thinking, text, tool_use_A]
user: [tool_result_A]
assistant: [thinking, text, tool_use_B]
user: [tool_result_B]

Invalid: Content AFTER tool_use

assistant: [thinking, tool_use_A, thinking, tool_use_B]  ← thinking AFTER tool_A!
user: [tool_result_A, tool_result_B]

Error: tool_use ids were found without tool_result blocks immediately after: tool_A

The API sees content after tool_use_A and interprets it as: "tool_A should have gotten its result before the assistant generated more content."

How This Happens

When a user aborts a tool mid-stream:

What should happen:

assistant: [thinking, tool_A]       ← END turn here
user: [tool_result_A: "aborted"]    ← INSERT this
assistant: [thinking, tool_B]       ← NEW turn
user: [tool_result_B]

What actually happens:

assistant: [thinking, tool_A, thinking, tool_B]  ← appended to SAME message
user: [tool_result_A, tool_result_B]             ← both results bundled

The sequence:

Model generates: thinking → tool_A
User aborts during tool execution
Client saves: thinking → tool_A (aborted)
BUG: Client does NOT end turn and add tool_result
Model retries, client appends: thinking → tool_B
Result: [thinking, tool_A, thinking, tool_B] - invalid pattern

Other causes:

Network interruption during streaming
Timeout kills the stream
Client crash during streaming
Rate limiting mid-response

Real-World Example

Saved message parts

prt_..5001 → step-start
prt_..7001 → reasoning: "The user wants me to create a markdown file..."
prt_..6001 → tool: write (ERROR, input: {})  ← ABORTED
prt_..b001 → reasoning: "The user wants me to create a markdown file..."
prt_..7001 → tool: write (COMPLETED)
prt_..c001 → step-finish

Converted to API format:

{
  "role": "assistant",
  "content": [
    {"type": "thinking", "thinking": "..."},
    {"type": "tool_use", "id": "toolu_01LiPBp", "name": "write", "input": {}},
    {"type": "thinking", "thinking": "..."},
    {"type": "tool_use", "id": "toolu_016rCwe", "name": "write", "input": {...}}
  ]
}

API Error:

messages.49: `tool_use` ids were found without `tool_result` blocks immediately after: toolu_01LiPBp

Workaround

Before sending to API, restructure messages with interleaved content:

Option A - Split into separate turns:

Original: assistant[thinking, tool_A, thinking, tool_B] + user[result_A, result_B]

Fixed:
  assistant[thinking, tool_A] + user[result_A]
  assistant[thinking, tool_B] + user[result_B]

Option B - Group tools at end (if results exist):

Original: [thinking, tool_A, thinking, tool_B]

Fixed: [thinking, thinking, tool_A, tool_B]

Note: Only works if the tool results are bundled together in the next message.

Test Results

Pattern	Result
`[thinking, text, tool_A, tool_B]` → `[result_A, result_B]`	✅ SUCCESS
`[thinking, tool_A, thinking, tool_B]` → `[result_A, result_B]`	❌ FAILED
`[thinking, text, tool_A, thinking, text, tool_B]` → `[result_A, result_B]`	❌ FAILED
`[thinking, text, tool_A]` → `[result_A]` → `[thinking, text, tool_B]` → `[result_B]`	✅ SUCCESS

Minimal Reproduction

curl -X POST https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: interleaved-thinking-2025-05-14" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-sonnet-4-20250514",
    "max_tokens": 2048,
    "thinking": {"type": "enabled", "budget_tokens": 1024},
    "messages": [
      {"role": "user", "content": "Do two things"},
      {
        "role": "assistant",
        "content": [
          {"type": "thinking", "thinking": "First.", "signature": "VALID_SIG_HERE"},
          {"type": "tool_use", "id": "tool_1", "name": "do_thing", "input": {"x": 1}},
          {"type": "thinking", "thinking": "Second.", "signature": "VALID_SIG_HERE"},
          {"type": "tool_use", "id": "tool_2", "name": "do_thing", "input": {"x": 2}}
        ]
      },
      {
        "role": "user",
        "content": [
          {"type": "tool_result", "tool_use_id": "tool_1", "content": "done"},
          {"type": "tool_result", "tool_use_id": "tool_2", "content": "done"}
        ]
      }
    ],
    "tools": [{"name": "do_thing", "description": "Do", "input_schema": {"type": "object", "properties": {"x": {"type": "integer"}}}}]
  }'

Expected error:

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "messages.1: `tool_use` ids were found without `tool_result` blocks immediately after: tool_1"
  }
}

I am also getting this error way too many times. Makes the current session completely unusable.

is there any update on this? i can't use the session anymore after this error comes. this is very bad and customer facing issue.

Same problem. #2214 seems to be a duplicate. I used Serena MCP when it did that.

Same issue on latest OC 1.14.28
after running /compact there is a high chance the session will get corrupted with:

messages.2: tool_use ids were found without tool_result blocks immediately after: toolu_01FcmYRSCKCYMzixsRUwQbbt. Each tool_use block must have a corresponding tool_result block in the next message.

only workaround is to export session and reference it in a new one via @ to try and preserve the context

If the error you got is the "tool_use ids were found without tool_result blocks" 400, that's a pretty common one after an interrupted tool call, and attachment/image turns seem to trigger it too. I made a small plugin that prevents it and recovers from it automatically:

https://github.com/viiqswim/opencode-compaction-guard

One line in opencode.json:

"plugin": ["opencode-compaction-guard@latest"]

It cleans up dangling pending/running tool calls before each request, and if the 400 still happens it reverts the failed turn so you don't have to throw away the session (you can /unrevert it). It's a stopgap until opencode fixes it upstream. The approaches are from #8497 and #1662.

If your error turns out to be something else (like a tool-argument validation failure), ignore me, this one's only for the tool_use/tool_result pairing error.

To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.

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Tool use id bug #5750

Description

OpenCode version

Steps to reproduce

Screenshot and/or share link

Operating System

Terminal

Tool Validation Error: Missing tool_result After Interruption

Root Cause

Summary

Error Message

The Rule

Valid vs Invalid Patterns

Valid: Tools grouped at end

Valid: Separate turns per tool

Invalid: Content AFTER tool_use

How This Happens

Other causes:

Real-World Example

Workaround

Test Results

Minimal Reproduction

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Tool use id bug #5750

Description

Description

OpenCode version

Steps to reproduce

Screenshot and/or share link

Operating System

Terminal

Activity

github-actions commented on Dec 18, 2025

rekram1-node commented on Dec 18, 2025

rekram1-node commented on Dec 18, 2025

deriegle commented on Dec 19, 2025

rekram1-node commented on Dec 19, 2025

deriegle commented on Dec 19, 2025

Mishkun commented on Dec 23, 2025

westito commented on Jan 8, 2026

Tool Validation Error: Missing tool_result After Interruption

Root Cause

Summary

Error Message

The Rule

Valid vs Invalid Patterns

Valid: Tools grouped at end

Valid: Separate turns per tool

Invalid: Content AFTER tool_use

How This Happens

Other causes:

Real-World Example

Workaround

Test Results

Minimal Reproduction

prolific commented on Feb 12, 2026

ArchishmanSengupta commented on Mar 26, 2026

XedinUnknown commented on Apr 1, 2026

faileon commented on Apr 28, 2026

viiqswim commented on Jun 29, 2026

github-actions commented on Aug 29, 2026

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