fix(opencode): repair malformed JSON in tool call arguments

[ahamza360]

Issue for this PR

Closes #23065

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

This PR fixes the recurring JSON parsing errors that occur when LLMs generate malformed/truncated JSON for tool call arguments.

Problem:
LLMs occasionally generate malformed/truncated JSON for tool call arguments, resulting in "JSON parsing failed" errors.

Solution:
Enhanced the experimental_repairToolCall callback in packages/opencode/src/session/llm.ts with improved JSON repair logic that:

• Detects JSON parsing errors in tool call arguments
• Attempts to repair common truncation issues:
  • Unterminated strings ("value → "value")
  • Missing closing brackets/braces ({ "key": "value" → { "key": "value" })
  • Nested structure completion
  • Complex cases like duplicated/overlapping JSON objects
• Falls back to existing 'invalid' tool handler if repair fails

This makes opencode more robust when dealing with imperfect LLM JSON output.

How did you verify your code works?

• Created unit tests covering various malformed JSON cases including complex scenarios
• Built and tested a working binary with the fix
• Verified the solution resolves the JSON parsing errors including the specific case with confluence_confluence_search_content

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

Hey! Your PR title Fix JSON parsing errors in tool call arguments doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search results, I found one potentially related PR:

Related PR:

• fix(opencode): retry transient provider failures and tool-call diff/input errors #15850 - "fix(opencode): retry transient provider failures and tool-call diff/input errors"
  • fix(opencode): retry transient provider failures and tool-call diff/input errors #15850
  • This PR addresses tool-call related errors, which is adjacent to the JSON parsing issue being fixed in PR fix(opencode): repair malformed JSON in tool call arguments #23064. However, it appears to focus on retry logic for transient failures rather than JSON repair specifically.

The current PR (#23064) appears to be the primary fix for JSON parsing errors in tool call arguments, addressing a specific issue that wasn't directly targeted in previous PRs.

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[github-actions]

Thanks for updating your PR! It now meets our contributing guidelines. 👍

[ahamza360]

Updated the PR with improved JSON repair logic that handles more complex cases including duplicated/overlapping JSON objects. This addresses the specific issue mentioned in the comments where tool calls like confluence_confluence_search_content were still failing with JSON parsing errors.

[ahamza360]

This PR has been superseded by #23067 which contains improved JSON repair logic that handles more complex cases including duplicated/overlapping JSON objects.