{"version":"2.1.293","anchor":"toolregister-accepts-isdeferred","canonical_anchor":"mods-can-register-deferred-tools","heading":"Plugins and mods can register deferred tools with isDeferred","tier":"use","area":"Plugins","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.293\/e\/toolregister-accepts-isdeferred","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.293","markdown":"### Plugins and mods can register deferred tools with `isDeferred`\n\n`$.tool.register` accepts an `isDeferred` true or false option, so plugin tools can load only when found through tool search\n\n**Unclear.** What marking a tool as deferred does at run time.\n\n**What**\n\nPlugins and mods can add their own tools with `$.tool.register`. It now accepts an `isDeferred` option. A deferred tool is not described to the model up front. It loads only when it is found through tool search.\n\n- The accepted shape is now `{ name, description, inputSchema?, isDeferred? }`. `name` is letters, digits, `_` or `-`, up to 64 characters.\n\n- `isDeferred` must be a true or false value. Anything else is rejected with an error that says so.\n\n- The MCP `tools\/list` response now adds extra fields to each tool from a helper.\n\n**Why**\n\nPlugin authors can keep rarely used tools out of the prompt, so they take no room until they are needed.\n\n- Area: Plugins\n- Names: `isDeferred`\n- Tier: Use it now\n- Useful: 4\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: no"}