Claude Code (Fable 5.1) vs Codex CLI (GPT-6-Astra) Comparison

# Claude Code — defining an org-wide MCP server (managed setting, v2.1.259+)
# Added to the managed-settings.json distributed by admin/IT; same entry shape as .mcp.json.
{
  "managedMcpServers": {
    "internal-docs": {
      "type": "sse",
      "url": "https://mcp.internal.example.com/sse",
      "headers": {
        "Authorization": "Bearer ${INTERNAL_MCP_TOKEN}"
      }
    }
  }
}

# Force all subagents onto a single model (enterprise cost control)
export CLAUDE_CODE_SUBAGENT_MODEL_FORCE=claude-sonnet-5

# Auto-reject anything that would prompt for approval in headless/CI
claude --permission-prompts none -p "Run the test suite and report failures"

# Changing effort level mid-session (no longer breaks prompt-cache as of v2.1.260)
claude
> /effort high

# Codex CLI — defining an MCP server (~/.codex/config.toml)
# This file is shared across the ChatGPT desktop app, Codex CLI, and the IDE extension.
# When `url` is given, the entry is treated as a streamable HTTP MCP server.
[mcp_servers.internal_docs]
url = "https://mcp.internal.example.com/mcp"
bearer_token_env_var = "INTERNAL_MCP_TOKEN"
startup_timeout_sec = 20
required = true

# With the Auto preset, read/edit/run commands automatically in the working directory
# (operations outside the directory or commands needing network access require approval)
codex --sandbox workspace-write "Refactor the auth module and run the unit tests"

# List cloud sessions from the terminal (to submit a task: codex cloud exec)
codex cloud list --json

# Add a plugin marketplace source, then list plugins (0.153.0+)
codex plugin marketplace add my-org/codex-plugins
codex plugin list --json