install.sh picks `python3` without a version check; requirements.txt needs >=3.10 (fails on macOS system Python 3.9.6)

Summary

install.sh selects the first python3 on PATH without checking its version, but requirements.txt requires Python ≥ 3.10. On macOS, /usr/bin/python3 is the system Python 3.9.6, so the install reliably fails at the dependency step.

The prerequisite check also advertises Python 3.8+, which is not achievable with the current pins.

Environment

• macOS (Apple Silicon), zsh
• System Python: 3.9.6 (/usr/bin/python3)
• Homebrew Python 3.12.13 present, but only as python3.12 (no python3 symlink on PATH)
• git 2.49.0, Claude Code CLI present, uv not installed

Reproduction

curl -fsSL https://raw.githubusercontent.com/zubair-trabzada/geo-seo-claude/main/install.sh | bash

Output (trimmed):

✓ Python found: Python 3.9.6
→ Creating isolated Python environment → /Users/<user>/.claude/skills/geo/.venv
✓ Virtual environment created
→ Installing Python dependencies into venv...
ERROR: Ignored the following versions that require a different python version: 12.1.0 Requires-Python >=3.10; ...
ERROR: Could not find a version that satisfies the requirement Pillow<13.0.0,>=12.1.0
ERROR: No matching distribution found for Pillow<13.0.0,>=12.1.0
✗ Failed to install dependencies.

Root cause

In install.sh, the python3 branch sets PYTHON_CMD with no version gate:

if command -v python3 &> /dev/null; then
    PYTHON_CMD="python3"          # <-- no version check
elif command -v python &> /dev/null; then
    ...
    if [ "$MAJOR" -ge 3 ] && [ "$MINOR" -ge 8 ]; then   # <-- only the fallback checks
        PYTHON_CMD="python"
    fi
fi

Note the asymmetry: the python fallback validates the version, but the far more common python3 path does not. The venv is then created with 3.9.6, and requirements.txt cannot resolve:

So the stated "Python 3.8+" prerequisite is unsatisfiable in practice; the real floor is 3.10.

Secondary impact: aborting here leaves a half-configured install

This is worth flagging because the failure is more than a missing-deps message. The dependency failure does exit 1, which skips the two steps that follow:

• "Pinning script shebangs to venv interpreter"
• "Rewriting skill & agent references to use the venv"

The skills/agents are already copied into ~/.claude at that point, still referencing bare python3. The result is an installed-looking skill whose commands fail later with a misleading:

ERROR: Required packages not installed. Run: pip install -r requirements.txt

Running pip install -r requirements.txt as suggested doesn't help, because the problem is the interpreter version, not a missing install step. This sends users down the wrong path.

Suggested fix

Probe for a ≥3.10 interpreter rather than taking python3 blindly:

PYTHON_CMD=""
for candidate in python3.13 python3.12 python3.11 python3.10 python3 python; do
    command -v "$candidate" &> /dev/null || continue
    if "$candidate" -c 'import sys; sys.exit(0 if sys.version_info >= (3, 10) else 1)' 2>/dev/null; then
        PYTHON_CMD="$candidate"
        break
    fi
done

if [ -z "$PYTHON_CMD" ]; then
    print_error "Python 3.10+ is required (found: $(python3 --version 2>&1 || echo none))."
    echo "  macOS: brew install [email protected]"
    exit 1
fi

This fails early with an accurate message instead of after the venv is built and files are copied.

Two smaller points:

1. Update the "Python 3.8+ is required" string (and any README mention) to 3.10+ so it matches the pins.
2. Consider whether the dependency failure should roll back or warn that ~/.claude now holds a partially configured skill, rather than exiting silently mid-install.

Workaround for anyone hitting this

Point python3 at a 3.10+ interpreter for the duration of the install:

brew install [email protected]
mkdir -p /tmp/pybin && ln -sf "$(brew --prefix)/bin/python3.12" /tmp/pybin/python3
PATH="/tmp/pybin:$PATH" bash install.sh

Verified on macOS with Python 3.12.13: all 25 dependencies install, shebangs pin correctly, markdown references rewrite, and fetch_page.py / citability_scorer.py run against live URLs.