ProxyPal bundled CLIProxyAPI does not strip `tools.defer_loading` (Claude Code + Codex compatibility)

[damaswangsa]

Description

When using ProxyPal as a local proxy for Claude Code, requests sent to Codex models fail with the following error:

API Error: 400 {"error":{"message":"Unknown parameter: 'tools.defer_loading'"}}

This happens because Claude Code sends the field:

tools.defer_loading

when Tool Search / MCP tools are enabled.

The CLIProxyAPI engine bundled inside ProxyPal appears to forward this parameter directly to upstream providers, which causes Codex/OpenAI-compatible APIs to reject the request.

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Relevant upstream fix

This issue appears to already be fixed in CLIProxyAPI:

router-for-me/CLIProxyAPI#1822

That PR strips unsupported fields like:

tools.defer_loading
cache_control

when translating Claude tool payloads for Codex/Gemini upstreams.

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Environment

ProxyPal version

0.4.8

Installation method

macOS .dmg release

Claude Code configuration

ANTHROPIC_BASE_URL=http://127.0.0.1:8317
ANTHROPIC_AUTH_TOKEN=proxypal-local
ANTHROPIC_DEFAULT_OPUS_MODEL=gpt-5.3-codex

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Steps to reproduce

1. Run ProxyPal
2. Configure Claude Code to use ProxyPal as ANTHROPIC_BASE_URL
3. Enable MCP tools / Tool Search
4. Send a tool-enabled request

ProxyPal forwards tools.defer_loading to upstream → upstream rejects the request.

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Current workaround

Disable tool search in Claude Code:

ENABLE_TOOL_SEARCH=false

However this disables lazy tool loading.

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Expected behavior

ProxyPal should strip unsupported parameters before forwarding requests upstream, specifically:

tools.defer_loading

This would match the behavior implemented in CLIProxyAPI PR #1822.

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Question

Does ProxyPal currently bundle a CLIProxyAPI version that includes the fix from PR #1822?

If not, would it be possible to update the bundled engine or implement equivalent filtering inside ProxyPal?

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Additional note

ProxyPal regenerates proxy-config.yaml, so manual payload.filter workarounds cannot be persisted.

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Thanks for building ProxyPal — it makes running Claude Code with local proxy stacks much easier.

[heyhuynhgiabuu]

This is already fixed!

The upstream fix (CLIProxyAPI PR #1822) was merged on March 4th and included in CLIProxyAPI v6.8.42. The CLIProxyAPIPlus sidecar synced this fix starting from v6.8.45-0.

You're on ProxyPal v0.4.8 which bundles sidecar v6.8.41-0 — one version before the fix landed.

Fix: Update to ProxyPal v0.4.11 which bundles sidecar v6.8.51-0 and includes the defer_loading + cache_control stripping for Codex and Gemini translators.

After updating, MCP tools / Tool Search should work without needing ENABLE_TOOL_SEARCH=false.