{"version":"2.1.318","anchor":"setup-code-mode-opt-in-step","canonical_anchor":"setup-code-mode-opt-in-step","heading":"Code mode gets a setup opt-in, warning banners and changes to MCP and file-read tools","tier":"notice","area":"Code Mode","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.318\/e\/setup-code-mode-opt-in-step","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.318","markdown":"### Code mode gets a setup opt-in, warning banners and changes to MCP and file-read tools\n\nNew code-mode pieces: a setup opt-in step, warning banners, MCP tools reached inside the REPL, and file reads refused in code mode\n\n**Unclear.** It does not say what decides whether the code mode opt-in step appears.\n\n**What**\n\nSeveral pieces of a feature called code mode appear in this release. Some of them concern MCP tools, which are extra tools that outside services provide to Claude. Others concern the REPL, an environment where Claude runs code:\n\n- Setup opt-in: the series of dialogs shown at startup has a new step. If a check passes, it shows `CodeModeOptIn` (`reviewCodeModeOptInInSetup`). Before, that step was an empty placeholder that showed nothing.\n\n- Warning banners: a new list has two warnings, `code-mode-opt-in` and `code-mode-remote-control`. The first appears when code mode reports a reason it refused, or a notice when code mode is \"on\". The second appears under a condition related to Remote Control.\n\n- Model notice: a new warning keyed `code-mode-model` shows notices about the model in code mode. It is high priority, lasts 15 seconds, and is cleared when there is no notice. It only runs when a build-time check, `ae()`, is true.\n\n- MCP tools in the REPL: when the REPL routes MCP tools, the message shown after waiting for servers now says their tools are \"callable inside the REPL environment\" and not as top-level tools. Before, it always said they were available to call directly. MCP servers are also skipped in REPL mode, with a warning.\n\n- Tool information: MCP tool information gains a `codeModeRouted` marker when `ae()` is true and the tools are routed this way. Before, nothing was added there.\n\n- File reads: the file-read tool now refuses, with reason `not_available` and detail `code_mode`, when a recipient check is present and code mode tools are in use.\n\n**Why**\n\nIf code mode reaches you, you may see an opt-in step at startup and new warnings. MCP tools may stop showing up as ordinary tools and instead be reached inside the REPL. Some file reads that worked before may be refused while code mode tools are in use.\n\n- Area: Code Mode\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 4\/5\n- Scope: individual\n- Heads-up: no"}