Guard JSON tree renderer against deep and oversized payloads

[baanish]

Motivation

• The JSON tree renderer previously expanded every nested object/array with no depth or node-count guard, which allows an attacker to craft deeply nested or very large JSON payloads that can cause excessive recursion/DOM creation and a client-side denial of service.

Description

• Add src/lib/json/tree-limits.ts which exports MAX_TREE_DEPTH, MAX_TREE_NODES, and exceedsTreeLimits, using an iterative traversal to detect excessive depth or node counts without recursion.
• Update src/components/renderers/json-renderer.tsx to parse the artifact, check exceedsTreeLimits, and when the payload is too large show a clear message and fall back to the Raw/code view instead of rendering the full tree.
• Add unit tests in tests/json-tree-limits.test.ts that verify small payloads are allowed and that overly deep or overly large payloads are blocked.
• The guard is implemented as a lightweight, reusable pre-check to preserve existing tree rendering for safe payloads while preventing unbounded DOM expansion.

Testing

• Ran npm test and all tests passed, including the new tests/json-tree-limits.test.ts.
• Ran npm run lint and the linter completed successfully.
• Ran npm run typecheck and TypeScript checks completed successfully.

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Codex Task

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

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Plan: Pro

Run ID: b965350b-b4ec-4ac9-bf82-3cea2a3cb30c

📥 Commits

Reviewing files that changed from the base of the PR and between 7cab153 and d3c9729.

📒 Files selected for processing (3)

• src/components/renderers/json-renderer.tsx
• src/lib/json/tree-limits.ts
• tests/json-tree-limits.test.ts

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• Post copyable unit tests in a comment
• Commit unit tests in branch codex/fix-client-side-dos-in-json-rendering

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[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Overview

This PR adds security improvements to protect against DoS attacks from large JSON payloads by implementing tree depth and node count limits.

Severity	Count
CRITICAL	0
WARNING	0
SUGGESTION	0

Security Assessment

The implementation correctly:

• Uses an iterative stack-based traversal (avoids stack overflow)
• Checks both depth (MAX_TREE_DEPTH = 64) and node count (MAX_TREE_NODES = 5000) limits
• Gracefully falls back to raw view when limits are exceeded
• Handles parse errors without accessing the tree limit property

Code Quality

• Clean separation of concerns with new tree-limits.ts module
• Type safety maintained with exported JsonValue type
• Good test coverage for edge cases

Files Reviewed (3 files)

• src/components/renderers/json-renderer.tsx - Modified to add tree limit checks
• src/lib/json/tree-limits.ts - New file with limit checking logic
• tests/json-tree-limits.test.ts - New test file

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: d3c9729a16

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[chatgpt-codex-connector]

Enforce node cap while expanding children

The size guard still does unbounded work for very wide payloads because exceedsTreeLimits pushes every child from entries before checking visitedNodes again, so an object/array with hundreds of thousands of top-level items will allocate a huge stack and can still freeze the UI even when maxNodes is small. This undermines the protection added in this commit for oversized JSON, since the expensive expansion happens before the function can return true.

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