{"version":"2.1.289","anchor":"plugin-agentspawn-hook-gets-mcp-requirement-and-unknown-sub","canonical_anchor":"plugin-agentspawn-hook-gets-mcp-requirement-and-unknown-sub","heading":"Clearer errors when a plugin launches an agent that cannot start","tier":"notice","area":"Plugin Hooks","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.289\/e\/plugin-agentspawn-hook-gets-mcp-requirement-and-unknown-sub","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.289","markdown":"### Clearer errors when a plugin launches an agent that cannot start\n\nPlugin agent launches now say when required MCP servers have no tools yet, and list the available agents when the named one does not exist\n\n**Unclear.** What turns on the plugin hooks involved is not clear.\n\n**What**\n\nPlugins can run a hook that launches an agent, meaning a separate Claude helper with its own task. Two of the messages shown when that launch fails are now clearer:\n\n- If the agent needs MCP servers (external tool integrations) that have no tools available yet, the message says so and points you to `\/mcp` to manage them\n\n- If the plugin names an agent type that does not exist, the message now lists the agents that are available\n\nBefore, the unknown-agent message referred to the wrong value and could say that none was named.\n\n**Why**\n\nYou can see what to fix: connect the missing servers through `\/mcp`, or pick one of the listed agents. The old unknown-agent path could also fail with an error of its own instead of showing a message.\n\n- Area: Plugin Hooks\n- Tier: You'll notice\n- Useful: 1\/5\n- Signal: 1\/5\n- Scope: individual\n- Heads-up: no"}