Fast Context for Pi

AI-driven semantic code search as a Pi coding agent package — powered by Windsurf's reverse-engineered SWE-grep protocol.

This is a port of fast-context-mcp from MCP to a native Pi extension. Search logic is unchanged: a remote Devstral model proposes rg / readfile / tree commands, they run locally, and you get file paths, line ranges, and grep keywords.

How It Works

You: "where is the authentication logic?"
         │
         ▼
┌─────────────────────────┐
│  Fast Context (pi ext)  │
│                         │
│  1. Maps project → /codebase
│  2. Sends query to Windsurf Devstral API
│  3. AI generates rg/readfile/tree commands
│  4. Executes commands locally (bundled rg)
│  5. Returns results to AI
│  6. Repeats for N rounds
│  7. Returns file paths + line ranges
│     + suggested search keywords
└─────────────────────────┘

Prerequisites

• Node.js >= 20
• Pi coding agent
• Windsurf / Devin account — free tier works (needed for an API key)

No system ripgrep install is required (@vscode/ripgrep is bundled).

Install

From npm:

pi install npm:pi-fast-context

From git:

pi install git:github.com/hemo94931/pi-fast-context

Try once without persisting:

pi -e npm:pi-fast-context

Project-local (writes .pi/settings.json):

pi install -l npm:pi-fast-context

From a local checkout:

pi install /absolute/path/to/pi-fast-context

After install, start pi and confirm the tools with /tools, or run /fast-context status.

Setup

Run /fast-context setup inside pi. It extracts a key from the local Devin/Windsurf install and writes:

{getAgentDir()}/extensions/pi-fast-context/config.json

getAgentDir() is Pi's agent config directory (~/.pi/agent by default, or $PI_CODING_AGENT_DIR). Do not hardcode that path.

You can also set WINDSURF_API_KEY yourself; the env var wins over config.json.

If local discovery finds no key, /fast-context setup prompts you to paste one. The value is shown as • per character (not plaintext, not a blank field). Enter saves it; an empty value errors without writing files; Esc cancels setup.

Search key resolution: env var → config.json → live Devin/Windsurf discovery.

Desktop credentials (used by setup / live discovery) are tried in this order: Devin, legacy Deviv, then Windsurf.

| Platform | Path | |----------|------| | macOS | ~/Library/Application Support/Devin/User/globalStorage/state.vscdb | | Windows | %APPDATA%/Devin/User/globalStorage/state.vscdb | | Linux | ~/.config/Devin/User/globalStorage/state.vscdb |

On WSL/Linux, discovery first checks Devin CLI credentials at ~/.local/share/devin/credentials.toml. If a Windows-extracted key returns 403 inside WSL, run devin login inside WSL and retry.

The key is never printed in full. /fast-context setup persists it in config.json for later sessions.

Tools and commands

fast_context_search

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | query | string | Yes | — | Natural language search query | | project_path | string | No | cwd | Absolute path to project root | | tree_depth | integer | No | 3 | Directory tree depth for repo map (1-6). Auto-falls back if tree exceeds 250KB. | | max_turns | integer | No | 3 | Search rounds (1-5) | | max_results | integer | No | 10 | Maximum files to return (1-30) | | exclude_paths | string[] | No | [] | Patterns excluded from the repository map |

Example output:

Found 3 relevant files.

  [1/3] /project/src/auth/handler.py (L10-60, L120-180)
  [2/3] /project/src/middleware/jwt.py (L1-40)
  [3/3] /project/src/models/user.py (L20-80)

grep keywords: authenticate, jwt.*verify, session.*token

[config] tree_depth=3, tree_size=12.5KB, max_turns=3

/fast-context

• /fast-context or /fast-context status — whether a key is available (env or config.json)
• /fast-context setup — extract a local Devin/Windsurf key and write {getAgentDir()}/extensions/pi-fast-context/config.json

Environment Variables

| Variable | Default | Description | |----------|---------|-------------| | WINDSURF_API_KEY | (config.json, then auto-discover) | Windsurf API key | | FC_MAX_TURNS | 3 | Search rounds per query | | FC_MAX_COMMANDS | 8 | Max parallel commands per round | | FC_TIMEOUT_MS | 30000 | Connect-Timeout-Ms for streaming requests | | FC_RESULT_MAX_LINES | 50 | Max lines per command output | | FC_LINE_MAX_CHARS | 250 | Max characters per output line | | FC_CACHE_DISABLED | (unset) | Disable the in-memory result cache (1 / true / yes / on) | | FC_CACHE_TTL_MS | 300000 | Result-cache TTL; <=0 disables caching | | FC_CACHE_MAX_ENTRIES | 200 | Maximum in-memory cache entries | | FC_ALLOW_INSECURE_TLS | (unset) | Set to 1 only when a trusted corporate proxy requires disabled TLS verification | | WS_MODEL | MODEL_SWE_1_6_FAST | Windsurf model name | | WS_APP_VER | 1.48.2 | Windsurf app version (protocol metadata) | | WS_LS_VER | 1.9544.35 | Windsurf language server version (protocol metadata) |

Available Models

Change the model with WS_MODEL.

Default: MODEL_SWE_1_6_FAST — fastest speed, richest grep keywords, finest location granularity.

Package layout

pi-fast-context/
├── package.json              # pi manifest (extensions)
├── extensions/index.ts       # Pi extension: tools + /fast-context
├── src/                      # Search core (unchanged from fast-context-mcp)
├── test/
└── README.md

How the Search Works

1. Project directory is mapped to virtual /codebase path
2. Directory tree generated at requested depth (default L=3), with automatic fallback if tree exceeds 250KB
3. Query + directory tree sent to Windsurf's Devstral model via Connect-RPC/Protobuf
4. Devstral generates tool commands (ripgrep, file reads, tree, ls, glob)
5. Commands executed locally in parallel (up to FC_MAX_COMMANDS per round)
6. Results sent back to Devstral for the next round
7. After max_turns rounds, Devstral returns file paths + line ranges
8. All rg patterns used during search are collected as suggested keywords
9. Diagnostic metadata appended so the calling model can retune parameters

Technical Details

• Protocol: Connect-RPC over HTTP/1.1, Protobuf encoding, gzip compression
• Model: Devstral (MODEL_SWE_1_6_FAST, configurable)
• Local tools: rg (bundled via @vscode/ripgrep), readfile (Node.js fs), tree (tree-node-cli), ls (Node.js fs), glob (Node.js fs)
• Auth: API Key → JWT (auto-fetched per session)
• Runtime: Node.js >= 20 (ESM). Pi loads extensions/index.ts via jiti — no compile step.

Dependencies

| Package | Purpose | |---------|---------| | @vscode/ripgrep | Bundled ripgrep binary (cross-platform) | | tree-node-cli | Cross-platform directory tree | | sql.js | Read Devin/Windsurf's local SQLite DB without a native build |

Pi core packages (@earendil-works/pi-coding-agent, typebox) are peer dependencies provided at runtime.

Credit

Search core ported from SammySnake-d/fast-context-mcp (MIT).

Not affiliated with Windsurf, Codeium, or Cognition.

License

MIT. Copyright (c) 2025 SammySnake-d; Copyright (c) 2026 hemo94931.