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AI Agent Plane

AI Agent Plane brings a coding agent right into the Lazarus IDE. You can chat with Claude Code, OpenCode, Pi, GitHub Copilot CLI, or another ACP agent in a dockable window. The agent does more than answer: it can use the IDE itself. It opens a unit at the right line, reads unsaved editor changes, compiles the project, reads the compiler errors and fixes them, and creates FastPlaz controllers and models.

This feature is available from the 2026 "Hero" release.

AI Agent Plane: the Lazarus editor with the AI agent chat

How It Works​

 You ──chat──► Agent Plane ──runs──► Coding agent
               (chat window)         (Claude Code, OpenCode,
                                      Pi, Copilot CLI, ACP)
                                            │
                                            │ tool call (MCP)
                                            ▼
 Source Editor ◄─────────────── MCP server in Lazarus IDE
 (open, edit, compile)          127.0.0.1:17826/mcp
  • The chat window runs the runtime (agent) you choose as a separate process. Communication is streamed, so thinking, tool calls, and answers show up as they happen.
  • An MCP server (Model Context Protocol) runs inside the Lazarus IDE process at http://127.0.0.1:17826/mcp. If the port is taken, the server uses the next port, up to 17835.
  • The MCP server is registered automatically with the agent started from Agent Plane. You do not need to copy the endpoint or token into the agent configuration, and there is no separate bridge process.
  • Through this MCP server the agent calls IDE tools: opening files, reading and editing the editor, searching the project, compiling, and the FastPlaz generators. The full list is in MCP Tools.

Supported Runtimes​

RuntimeHow it connects
Claude CodeThe MCP server is passed through --mcp-config (a temporary JSON file). Tools appear as mcp__fastplaz__<tool>. Claude Code questions (AskUserQuestion) are shown as question cards in the chat.
OpenCodeThrough ACP (Agent Client Protocol); the MCP server is sent in session/new.
PiNative RPC mode. MCP is registered through a temporary extension (needs Pi 1.4.0 or later).
GitHub Copilot CLIThrough ACP, with --allow-tool=fastplaz so Copilot does not ask a second time.
Other ACP agentsThrough ACP, if the agent supports MCP over HTTP.

Runtime, model, and thinking effort can be changed directly from the chat window. The last model used is remembered per runtime.

note

The runtime (for example claude, opencode, pi, or copilot) must already be installed and logged in on your computer. Agent Plane runs that runtime; it does not replace it.

Getting Started​

  1. Install the FastPlaz package. Make sure tools/fastplaz_tools.lpk is installed in Lazarus. See Installation.

  2. Choose a runtime. Open FastPlaz → Configuration, tab AI Harness. Choose the runtime, model, and thinking effort, then click Run Test to check the runtime and the MCP server.

  3. Open Agent Plane. Choose FastPlaz → Agent Plane (just above Database Explorer). The chat window can be docked next to the Source Editor.

  4. Start chatting. Type your request, for example:

    • "Explain what this project does."
    • "Create an API controller customer with a model for the customers table."
    • "Compile the project and fix the errors."

    Press Shift+Enter for a new line, Enter or the Send button to send.

Configuration (AI Harness Tab)​

Agent Plane settings are in the same form as Fast Code Configuration, on the AI Harness tab.

SettingDescription
RuntimeClaude Code, OpenCode, Pi, or GitHub Copilot CLI
ModelThe model list is detected automatically when a runtime is selected
Thinking effortauto, off, minimal, low, medium, high, xhigh
Enable IDE tools (MCP)aiplane/mcp_enabled, on by default. When off, the chat still works without IDE tools
MCP portaiplane/mcp_port, default 17826 (1024–65535)
Auto reloadaiplane/auto_reload: files changed by the agent are reloaded in the editor automatically, without the IDE confirmation dialog
Run TestChecks that the runtime can be started and the MCP server responds

You Stay in Control​

Every MCP tool has a permission level. Tools that change files, compile, or delete something show a permission card in the chat and wait for your answer.

LevelBehavior
autoRuns right away. Only for tools that read, for example read_editor, search_project, project_info
ask once per sessionAsks first; "Allow for this session" is remembered until the session is reset. For example edit_text, compile_project, the FastPlaz generators
always askAlways asks. For tools that cannot be undone: revert_file and clean_and_compile_project

The permission card shows the tool title, a summary of what will happen, and its arguments.

Changes from edit_text go into the editor as a single undo step, so they can be undone with Ctrl+Z. The file is not written to disk until you (or the agent, with permission) save it.

Security​

  • The MCP server listens on 127.0.0.1 only.
  • Every request must carry Authorization: Bearer <token>. A random token is made each time the server starts, and it is never written into your own agent configuration.
  • Requests with a non-loopback Origin header are refused (DNS rebinding protection).
  • Read tools only read files in the project and its search paths. Edit tools only change files in the project directory, project files, and files you have open; libraries such as FastPlaz itself are not changed. Generators only write inside the project directory.

FastPlaz Reference for Agents​

So the agent does not guess the API, the MCP server provides a FastPlaz reference as the resource fastplaz://reference (and the tool get_fastplaz_reference for agents that do not read resources). It covers project layout, controllers, routes, request and session data, themes and template tags, TSimpleModel, TJSONUtil, config.json, helpers, the workflow in the IDE, and common pitfalls.

The agent is also told to use the generators (create_api_controller, create_model, etc.) instead of writing controllers and models by hand.

The reference text comes from the file tools/templates/agent/fastplaz-reference.md and is read again on every request, so it can be edited without rebuilding the IDE.

See Also​