claude-patch

Community-contributed binary patches for Claude Code CLI — unlock hard-coded limitations without waiting for upstream changes.

Disclaimer: This is unofficial and not supported by Anthropic. It modifies the Claude Code binary. Use at your own risk. Keep backups and know how to reinstall Claude Code.

Install

Option A: Agent Skills CLI (works with Claude Code, Cursor, Copilot, etc.)

npx skills add huybuidac/claude-code-patchkit -g

The -g flag installs globally (user-level) so the skill is available in all projects. Without it, the skill is only available in the current project.

Option B: Claude Code plugin system

/plugin marketplace add huybuidac/claude-code-patchkit
/plugin install claude-patch

Prerequisites

• Node.js (LTS) on PATH — all platforms; scanning and patching run through one Node tool
• codesign on macOS (ships with Xcode Command Line Tools)
• Claude Code installed as a native binary, and write permission to it

Platforms: macOS arm64 (tested) / x86_64 (expected), Windows 11 arm64 (tested) / 10-11 x64 (expected), Linux (untested).

Usage

Inside a Claude Code session:

/claude-patch                               # Interactive mode
/claude-patch apply subagent-model          # Apply specific patch
/claude-patch apply auto-compact-by-model   # Claude ≈400K, GPT ≈300K
/claude-patch revert subagent-model         # Revert to backup
/claude-patch status                        # Show all patch states

Available Patches

Patch	Description	Risk
subagent-model	Unlock model param on Agent tool — use any model id per-call	Low
auto-compact-by-model	Model-aware extended-context compact targets: Claude ≈400K, GPT ≈300K	Medium

Model-aware auto-compaction

The auto-compact-by-model patch targets Claude Code’s central compaction resolver (functionally tested on 2.1.208; derivation verified through 2.1.233). For models whose resolved context ceiling is above 200K, it sets internal windows that normally trigger at approximately:

• claude-*: 400K actual context tokens
• gpt-*: 300K actual context tokens

A numeric CLAUDE_CODE_AUTO_COMPACT_WINDOW remains the fallback for other models. Matched extended-context Claude/GPT rules take precedence, so an existing global value can stay configured for standard or unknown model families. CLAUDE_AUTOCOMPACT_PCT_OVERRIDE may still compact earlier.

The patch creates a backup plus a revert sidecar, and requires a Claude Code restart because running processes keep the old executable mapped.

How It Works

Claude Code is distributed as a bun-compiled binary with embedded JS bundles. Some behaviors are locked behind hard-coded Zod schemas. This is an Agent Skill — Claude reads the patch definitions and runs the procedure with your confirmation before any write. Each apply is a length-preserving byte swap:

1. Derive the anchor — see below
2. Context guards — stable strings before and after must match, and any variable binding the replacement depends on must be proven, not assumed
3. State detection — unpatched / patched / abnormal, before acting
4. Backup — <binary>.bak.<timestamp>, plus a <binary>.rtk-<patch>.json sidecar recording the original bytes
5. Verified write — each offset is checked against its expected bytes before being overwritten, so a stale offset aborts instead of corrupting the binary
6. Signature — ad-hoc codesign on macOS; on Windows Authenticode becomes HashMismatch (binary still runs)
7. Self-verify — re-scan and confirm the marker count

Anchors are derived, not hardcoded

The bundler renames minified identifiers every few builds. A hardcoded anchor then matches 0 times — indistinguishable from "the feature was removed" — so routine drift looks like a broken fingerprint. Real examples from subagent-model: .enum([...]) → xr([...]) → Mr([...]), three rewrites in four months.

So each patch derives its anchor at scan time from landmarks that don't move: string literals the product ships (.describe() text, source:"…" labels) and positional locals the bundler assigns by position rather than name. The patch definitions document the derivation rule instead of the bytes.

This also covers bundle multiplicity — the JS bundle is embedded 1 or 2 times depending on platform/version (macOS ≤ 2.1.132 = 2, ≥ 2.1.133 = 1, Windows = 1). Landmarks are counted, never asserted.

Windows specifics

claude.exe is locked while running, so writes go to a copy that then takes the original's path — renaming a running image only updates the directory entry. Restart Claude Code afterwards, and clean up any *.replacing.* file once the old process has exited.

Safety

• Never patches without explicit user confirmation
• Aborts if fingerprint doesn't match (schema changed in new version)
• Always creates backup before modifying
• Re-applies required per Claude Code update (new binary = clean slate)

Contributing

1. Copy skills/claude-patch/patches/TEMPLATE.md
2. Register the derivation in patch-bin.js and document the rule in your .md
3. Test on at least 2 Claude Code versions
4. Submit a PR

Requirements

• Anchor derived from a stable landmark — not a pasted byte sequence containing minified names
• Length-preserving replacement, ideally referencing only positional locals (they survive renames)
• A guard that proves whatever the replacement assumes about the surrounding code
• Unique, permanently stable marker string for state detection
• Tested version list, distinguishing functionally tested from structurally verified

Platform Support

• macOS arm64 (Apple Silicon) — tested
• macOS x86_64 — should work (untested)
• Windows 11 arm64 — tested
• Windows 10/11 x64 — should work (untested)
• Linux — binary layout may differ, contributions welcome

Recovery

• Normal route: /claude-patch revert <patch>, or node patch-bin.js revert --patch <patch>. It prefers the <binary>.rtk-<patch>.json sidecar (exact reverse-patch), falls back to a content-validated <binary>.bak.<timestamp>, and snapshots <binary>.preRevert.<ts> first.
• Keep the sidecar. A patched binary alone cannot reconstruct a drifted minified alias — only its length survives.
• Don't restore a backup by size or filename. On macOS the backup is Apple-signed while the patched binary is ad-hoc signed, so sizes legitimately differ; and Claude Code re-bundles within a dot-version, so same name ≠ same build. Let revert validate it by content.
• Clean up Windows *.replacing.* files after Claude Code has exited (they may stay on disk while the old process is still mapped)
• To reinstall Claude Code: delete the install dir (~/.local/share/claude/ on Unix, %USERPROFILE%\.local\bin\claude.exe on Windows) and re-run the installer

License

MIT