RepoPrompt MCP for Pi (pi-repoprompt-mcp)

This extension provides a single tool (rp) that exposes RepoPrompt MCP tools to Pi, includes branch-safe window and tab binding (auto-detect and bind to window by cwd, auto-bind to safe tab, persist and restore across sessions and session tree nodes, and interactive selection of windows and tabs) and batches of read files (automatically selected as context in the RepoPrompt desktop app), renders RepoPrompt tool outputs (syntax + diff highlighting), and applies guardrails for destructive operations.

The extension's window- and tab-related management features allow a workflow where new Pi sessions automatically attach to the required workspace and tab without clobbering your, or other agents', parallel usage of RepoPrompt. Because it recovers the window, tab, and auto-selected read-files context when you rewind via /tree or restore a session, all the context the agent has built up (and automatically selected in the RepoPrompt app) by reading files and slices up to that point always remains available in the app for RP Chat (see /rp oracle below) or external "oracle" (e.g. GPT-x Pro) use cases. Recovery is based on the required root(s) of the saved selection state, so it can reattach to any open workspace that already contains those roots rather than requiring the original workspace name; if multiple open workspaces satisfy that requirement and cwd does not disambiguate them, then you should re-bind with /rp bind.

Installation

From npm:

pi install npm:pi-repoprompt-mcp

From the dot314 git bundle (filtered install):

Add to ~/.pi/agent/settings.json (or replace an existing unfiltered git:github.com/w-winter/dot314 entry):

{
  "packages": [
    {
      "source": "git:github.com/w-winter/dot314",
      "extensions": ["extensions/repoprompt-mcp/src/index.ts"],
      "skills": [],
      "themes": [],
      "prompts": []
    }
  ]
}

Features

Window and tab binding

• Auto-binds to the RepoPrompt window that matches process.cwd() (by workspace roots, resolving symlinks to their real paths before matching)
  • If multiple windows match, you're prompted to pick one
  • Window binding is (optionally) persisted across session reloads and session tree nodes
• If a bound window has an existing tab with zero selected files and no chats, the extension binds to that tab; otherwise it provisions a new tab and binds to that
• Deterministically reconciles the session tree node's bound tab, and can restore the tab already associated with that node or provision a new safe tab when needed
• User-driven binding via /rp bind (windows) or /rp tab (tabs); agents can use rp({ bind: ... })
• In addition to window bindings, tab bindings and auto-selected read-files context is stored and automatically recovered across node rewinds via /tree, different sessions (e.g., created via /fork), and resumed sessions

Forked sessions inherit the parent session-plus-node's window, tab, and auto-selected context snapshot at the fork point (unless you rewind in the forked session and switch window/tab/etc.), then can diverge independently as later reads or manual tab switches are performed in the child session. Binding is non-invasive, in that it doesn't change RepoPrompt's globally active window, and automatic tab provisioning uses background tabs (focus=false) without stealing UI focus. This is to prevent interference when multiple agents (or your manual usage of RepoPrompt in parallel to a Pi session) are using this extension and need to target different windows or tabs simultaneously.

Output rendering

• Syntax highlighting for code blocks and codemaps in read_file, and for code blocks in outputs of apply_edits, file_actions create/delete, and git
• Common non-mutating RepoPrompt actions (read_file, file_search, get_file_tree, get_code_structure, workspace_context, routing helpers like manage_workspaces, and control/discovery actions like windows/bind/status/search/describe) get concise request-driven call/result summaries in collapsed mode. The call line carries intent while the result line carries outcome, so the transcript stays compact without echoing the same label twice. These summaries are derived from the arguments Pi sent, not by parsing RepoPrompt's prose output, and unknown tools fall back to normal collapsed rendering

• RepoPrompt apply_edits calls are forwarded with verbose: true by default (unless raw: true), while the returned diff is normalized into details.diff and presented to the agent as a terse summary. The same is done for file_actions create/delete outputs, so you see all edited/created/deleted LOC with rich rendering but the extension prevents the context window from getting bloated by round-tripping tool I/O tokens
• Adaptive diff rendering for RepoPrompt git and apply_edits outputs by default (diffViewMode: "auto" picks split, unified, compact, or summary at render time based on pane width). This uses the active Pi theme's toolDiffAdded, toolDiffRemoved, and toolDiffContext colors (typically mapped to chosen hues for green and red), and its visual design and rendering logic are indebted to MasuRii/pi-tool-display. Two different examples at different pane widths:

• Generic fenced diff blocks, and adaptive-diff parse failures, fall back to a simpler diff renderer, which uses delta if installed or otherwise the built-in highlighter
• Markdown-aware styling for headings and lists

Safety checks

• Delete operations are blocked unless you pass allowDelete: true
• Optional edit confirmation gate for edit-like operations (confirmEdits)
• Warn on in-place workspace switches (when applicable)

Requirements

• RepoPrompt MCP server configured and reachable (stdio transport)
  • If the server is not configured/auto-detected, the extension will still load, but rp(...) will error until you configure it
• rp-cli available in PATH is recommended (used as a fallback for window discovery)

Compatibility notes

This extension tries to be tolerant of tool name prefixing (e.g. RepoPrompt_list_windows vs list_windows), but it is still dependent on a small set of capabilities and their semantics remaining reasonably stable across RepoPrompt versions:

• Window discovery: list_windows
  • If list_windows is not exposed by the MCP server, the extension falls back to rp-cli -e 'windows'
  • If neither is available, window listing/binding features will be limited
• Workspace root discovery (auto-bind by cwd): get_file_tree with { type: "roots" } (scoped by _windowID)
  • If unavailable (or if parameters/semantics change), auto-binding may be disabled or less accurate
• Selection summary: manage_selection with { op: "get", view: "files" } and { op: "get", view: "summary" }
  • If these are unavailable (or if parameters/semantics change), the status output may omit file/token counts

If RepoPrompt renames/removes these tools or changes their required parameters/output formats, this extension may need updates

Usage

Commands

• /rp status — show status (connection + binding), including the currently bound tab name and a label like [bound, in-focus] or [bound, out-of-focus], plus current selected file counts and estimated token counts

• /rp windows — list available RepoPrompt windows
• /rp bind — interactive workflow for choosing the RepoPrompt window
• /rp bind <id> [tab] — direct option if you already know the target window id (and optionally an exact tab name or tab id); when [tab] is omitted, the extension restores the branch's tab for that window or provisions a fresh background tab once
• /rp tab — interactive tab picker for the current bound window, with Create new tab as the first option followed by existing tab names
• /rp tab new — create and bind a fresh tab on the current bound window
• /rp tab <name-or-id> — bind an existing tab on the current bound window by name or id
• /rp oracle [--mode <chat|plan|edit|review>] [--name <chat name>] [--continue|--chat-id <id>] <message> — ask RepoPrompt chat with current selection context. If --mode not specified, uses oracleDefaultMode config.
• /rp reconnect — reconnect to RepoPrompt

Tool: rp

Examples:

// Status (connection + binding)
rp({ })

// List windows (best-effort; uses MCP tool if available, otherwise rp-cli)
rp({ windows: true })

// Bind to a specific window (does not change RepoPrompt active window)
rp({ bind: { window: 3 } })

// Bind to an exact tab in that window
rp({ bind: { window: 3, tab: "T2" } })

// Search or describe tools
rp({ search: "file" })
rp({ describe: "apply_edits" })

// Call a RepoPrompt tool (binding args are injected automatically)
rp({ call: "read_file", args: { path: "src/main.ts" } })

// Edit confirmation gate (only required if confirmEdits=true in config)
rp({
  call: "apply_edits",
  args: { path: "file.ts", search: "old", replace: "new" },
  confirmEdits: true
})

// Delete guard override
rp({
  call: "file_actions",
  args: { action: "delete", path: "temp.txt" },
  allowDelete: true
})

Configuration

Create ~/.pi/agent/extensions/repoprompt-mcp.json:

{
  "command": "rp-mcp-server",
  "args": [],

  "autoBindOnStart": true,
  "persistBinding": true,

  "confirmDeletes": true,
  "confirmEdits": false,

  "readcacheReadFile": true,
  "autoSelectReadSlices": true,
  "oracleDefaultMode": "chat",

  "collapsedMaxLines": 3,
  "diffViewMode": "auto",
  "diffSplitMinWidth": 120,
  "suppressHostDisconnectedLog": true
}

collapsedMaxLines controls how many rendered lines of RepoPrompt tool output Pi shows before the result is expanded for the generic fallback path. In addition, the extension now emits hand-authored one-line or two-line collapsed summaries for common non-mutating actions like read_file, file_search, get_file_tree, get_code_structure, workspace_context, windows, bind, and status; these are derived from Pi's own request metadata rather than RepoPrompt's returned prose. Unknown or unsupported tools still fall back to the normal collapsedMaxLines behavior. LOC-changing operations are the other exception: verbose RepoPrompt apply_edits and rendered file_actions create/delete results ignore collapsedMaxLines once normalized into details.diff, so the full rendered code changes remain visible.

Options:

| Option | Default | Description | |---|---:|---| | command | auto-detect | MCP server command | | args | [] | MCP server args | | env | unset | Extra environment variables for the MCP server | | autoBindOnStart | true | Auto-detect and bind on session start, then reconcile the branch-safe tab for the chosen window | | persistBinding | true | Persist window and tab bindings in Pi session history for branch-safe replay | | confirmDeletes | true | Block delete operations unless allowDelete: true | | confirmEdits | false | Block edit-like operations unless confirmEdits: true | | readcacheReadFile | false | Enable pi-readcache-like caching for RepoPrompt read_file calls (returns unchanged markers/diffs on repeat reads to save on tokens and prevent context bloat) | | autoSelectReadSlices | true | Automatically track read_file calls by adding slices/full-file selection via manage_selection, so chat_send (or a manually created chat in the RP app) uses everything the agent has read as context; these file/slice selections are branch-safe across /tree rewinds and /forked session branches via extension-owned snapshot replay | | oracleDefaultMode | "chat" | Default mode for /rp oracle when --mode is omitted (chat, plan, edit, or review) | | collapsedMaxLines | 3 | Lines shown in collapsed view | | diffViewMode | "auto" | Diff layout for RepoPrompt git / apply_edits fenced diff output (auto, split, unified) | | diffSplitMinWidth | 120 | Minimum render width before diffViewMode: "auto" uses split diff layout | | suppressHostDisconnectedLog | true | Filter noisy stderr from macOS repoprompt-mcp (disconnect/retry bootstrap logs) | | autoLaunchApp | false | Auto-launch the RepoPrompt app when the MCP server is unreachable at startup | | appPath | inferred | Explicit path to Repo Prompt.app; if omitted, inferred from the .app ancestor of command |

Automatic tab restoration and provisioning is driven by autoBindOnStart and persistBinding; there is no separate tab-only configuration surface. Adaptive diff layout applies only to RepoPrompt git and apply_edits outputs that arrive as fenced diff blocks; other rendered output stays on the existing text-based path.

Note: when readcacheReadFile is enabled, the extension may persist UTF-8 file snapshots to an on-disk content-addressed store under <repo-root>/.pi/readcache/objects to compute diffs/unchanged markers across calls. Common secret filenames (e.g. .env*, *.pem) are excluded, but this is best-effort

Readcache gotchas

• raw: true disables readcache (and rendering). Don't use unless debugging
• Need full content? use bypass_cache: true in read_file args
• Multi-root: use absolute or specific relative paths (MCP read_file has no RootName: disambiguation)

Troubleshooting

"Not connected to RepoPrompt"

• Ensure RepoPrompt is running
• Verify the MCP server command in config
• Run /rp reconnect

Pi becomes unresponsive after closing/restarting RepoPrompt

If the RepoPrompt MCP server stops responding (for example, if the RepoPrompt app is closed while Pi stays open), tool calls may time out. When that happens, the extension will drop the connection and you can recover with /rp reconnect.

If RepoPrompt is not running when Pi starts, the extension auto-pauses itself after a quick connection timeout. While paused, the rp tool returns a short error directing the agent to use native tools. Run /rp reconnect once RepoPrompt is open to resume, and the agent will be notified that rp is available again.

If autoLaunchApp is enabled, the extension will try to open the RepoPrompt app automatically before pausing. The app path is inferred from the command config (e.g. /Applications/Repo Prompt.app/Contents/MacOS/repoprompt-mcp → /Applications/Repo Prompt.app), or you can set appPath explicitly. After launching, the extension waits a few seconds and retries the connection once; if that also fails, it auto-pauses as usual.

"No matching window found"

• Your cwd may not match any RepoPrompt workspace root
• Use /rp windows to list windows
• Use /rp bind to pick one

Window listing doesn't work

• If the MCP server does not expose a list_windows tool, this extension uses rp-cli -e 'windows'
• Make sure rp-cli is installed and on your PATH
• If RepoPrompt is in single-window mode, rp-cli -e 'windows' may report single-window mode

Delete operation blocked

• Pass allowDelete: true on the rp call

License

MIT