diff --git a/.please/docs/decisions/0001-native-tree-sitter.md b/.please/docs/decisions/0001-native-tree-sitter.md
new file mode 100644
index 0000000..a478890
--- /dev/null
+++ b/.please/docs/decisions/0001-native-tree-sitter.md
@@ -0,0 +1,59 @@
+# ADR 0001 — Use Native Tree-sitter Bindings via `@kreuzberg/tree-sitter-language-pack`
+
+- **Status**: Accepted
+- **Date**: 2026-05-28
+- **Deciders**: csp maintainers
+- **Supersedes**: the "No native add-ons" guideline previously stated in `ARCHITECTURE.md`
+
+## Context
+
+`@pleaseai/csp` ports MinishLab/semble from Python to TypeScript / Bun. Semble parses source code with tree-sitter via the Python `tree-sitter-language-pack`, which exposes a few hundred pre-built grammars through native bindings. The chunker (`src/semble/chunking/core.py`) depends on this coverage — every supported language has an entry in `EXTENSION_TO_LANGUAGE`, and missing a grammar degrades silently to line-based fallback chunking.
+
+For the TypeScript port we considered two options:
+
+1. **`web-tree-sitter`** (WASM). Portable across Linux / macOS / Windows / containers, no native build step. This was the original `ARCHITECTURE.md` guidance ("No native add-ons").
+2. **`@kreuzberg/tree-sitter-language-pack`** (NAPI). Native bindings, ships pre-compiled binaries for macOS / Linux / Windows. Closer parity with the upstream Python implementation.
+
+The trade-off is portability (WASM wins) vs. coverage + startup cost + parity (NAPI wins).
+
+## Decision
+
+**Adopt `@kreuzberg/tree-sitter-language-pack`** as the canonical tree-sitter binding for csp.
+
+Rationale:
+
+- **Parity with semble.** Upstream uses the same multi-grammar `tree-sitter-language-pack` package. Matching the same set of grammars means the TypeScript port can adopt semble's extension → language map (`src/semble/index/files.py`) without per-language audit.
+- **Coverage.** 305 languages out of the box (per the package's published description). Sourcing equivalent WASM grammars individually for each language would be a multi-week chore and add a runtime fetcher.
+- **Startup cost.** Native parsers load once when the process boots; WASM grammars must be fetched/instantiated per language, which slows the first index of a polyglot repo.
+- **Pre-built binaries.** `@kreuzberg/tree-sitter-language-pack` publishes prebuilds for macOS (arm64 / x64), Linux (arm64 / x64, glibc + musl) and Windows (x64). Most users get a binary download, not a node-gyp compile.
+
+## Consequences
+
+### Positive
+
+- Day-1 support for the same language set as semble.
+- No WASM loader, no asset bundling for grammars.
+- Hot-path parsing runs at native speed (a measurable factor for `csp index` on large repos).
+
+### Negative
+
+- Installs now require a supported platform. Users on exotic targets (FreeBSD, Alpine arm64 without musl prebuilds, sandboxed environments without binary loading) may fail to install. The csp README will list supported platforms explicitly.
+- Bun must support loading the NAPI prebuild on the install target. Tested on Bun ≥ 1.3.10 (macOS arm64 / Linux x64).
+- The package adds ~50–100 MB to `node_modules` (native binaries × language grammars). This is acceptable for a developer tool but should be documented.
+
+### Neutral
+
+- Future work may introduce an optional WASM fallback for browser / sandboxed environments. That is out of scope for this ADR — the primary distribution path remains native.
+- Other native add-ons remain discouraged. Any additional NAPI / node-gyp dependency requires its own ADR.
+
+## Alternatives considered
+
+- **`web-tree-sitter` + curated grammar list.** Rejected: coverage gap vs. semble (would need ~50+ separate `tree-sitter-*-wasm` packages, none of which is a maintained drop-in) and per-language loader complexity.
+- **Bun-only tree-sitter via FFI.** Rejected: ties the project to Bun-only, loses Node.js 22+ support promised in `engines`.
+- **Wait and write our own chunker without tree-sitter.** Rejected: semble's chunk quality (definition-bounded, comment-attached) depends on AST awareness; a line-window chunker would regress search precision measurably.
+
+## References
+
+- Upstream: `src/semble/chunking/core.py`, `src/semble/index/files.py` in the upstream [MinishLab/semble](https://github.com/MinishLab/semble) repository.
+- `@kreuzberg/tree-sitter-language-pack` — <https://www.npmjs.com/package/@kreuzberg/tree-sitter-language-pack>
+- Previously stated guideline in `ARCHITECTURE.md` ("No native add-ons") is amended in the same commit that introduces this ADR.
diff --git a/.please/docs/decisions/index.md b/.please/docs/decisions/index.md
index 1db25c5..8bf7200 100644
--- a/.please/docs/decisions/index.md
+++ b/.please/docs/decisions/index.md
@@ -4,3 +4,4 @@
 
 | ADR | Title | Date | Status |
 |-----|-------|------|--------|
+| [0001](0001-native-tree-sitter.md) | Use Native Tree-sitter Bindings via `@kreuzberg/tree-sitter-language-pack` | 2026-05-28 | Accepted |
diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 9ed62e2..f06d534 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -124,7 +124,7 @@ For **understanding ranking decisions** (the heart of why csp beats grep):
 
 **Algorithmic ports must read the original Python source, not memory.** Use `ask src github:MinishLab/semble@main` and read the relevant `src/semble/*.py` before writing TypeScript. When porting a non-trivial function, leave a `// Port of src/semble/<path>::<name>` comment so reviewers can diff against the source of truth.
 
-**No native add-ons.** Tree-sitter must be `web-tree-sitter` (WASM), not `node-tree-sitter`. This keeps installs portable across Linux / macOS / Windows / containers without C toolchains, and works under Bun where many node-gyp packages still misbehave.
+**Native tree-sitter is allowed via `@kreuzberg/tree-sitter-language-pack`.** This NAPI package ships pre-compiled binaries for macOS / Linux / Windows and gives parity with upstream semble's `tree-sitter-language-pack` Python bindings (305 languages out of the box, no WASM loader overhead). The decision is captured in [ADR 0001](.please/docs/decisions/0001-native-tree-sitter.md). Other native add-ons remain discouraged — anything beyond tree-sitter needs its own ADR justifying the loss of portability under Bun and across container images that lack a C toolchain.
 
 **Bilingual README must stay in sync.** Any public-API change (CLI flag, library symbol, MCP tool, config option, stats path) updates **both** `README.md` and `README.ko.md` in the same commit. The CLAUDE.md captures this as load-bearing.
 
diff --git a/package.json b/package.json
index 6b31303..3c24e89 100644
--- a/package.json
+++ b/package.json
@@ -52,6 +52,14 @@
     "test": "bun test",
     "prepublishOnly": "bun run build"
   },
+  "dependencies": {
+    "@huggingface/transformers": "^4.2.0",
+    "@kreuzberg/tree-sitter-language-pack": "^1.8.1",
+    "@modelcontextprotocol/sdk": "^1.29.0",
+    "chokidar": "^5.0.0",
+    "commander": "^14.0.3",
+    "ignore": "^7.0.5"
+  },
   "devDependencies": {
     "@pleaseai/eslint-config": "^0.0.3",
     "@types/bun": "latest",
diff --git a/src/agents/claude.md b/src/agents/claude.md
new file mode 100644
index 0000000..238afdd
--- /dev/null
+++ b/src/agents/claude.md
@@ -0,0 +1,56 @@
+---
+name: csp-search
+description: Code search agent for exploring any codebase. Use for finding code by intent, locating implementations, understanding how something works, or discovering related code. Prefer over Grep/Glob/Read for any semantic or exploratory question.
+tools: Bash, Read
+---
+
+Use `csp search` to find code by describing what it does or naming a symbol/identifier, instead of grep:
+
+```bash
+csp search "authentication flow" ./my-project
+csp search "save_pretrained" ./my-project
+csp search "save model to disk" ./my-project --top-k 10
+```
+
+If you anticipate doing more than one search, use `csp index` to create an index.
+
+```bash
+csp index ./my-project -o my_index
+```
+
+You can then reuse this index later on:
+
+```bash
+csp search "save_pretrained" --index my_index
+```
+
+An index is not automatically updated, so if the code changes significantly, reindex. If you notice stale results while resolving searches to files, reindex.
+
+Use `--content docs` to search documentation and prose, `--content config` for config files (yaml, toml, etc.), or `--content all` to search code, docs, and config:
+
+```bash
+csp search "deployment guide" ./my-project --content docs
+csp search "database host port" ./my-project --content config
+csp search "authentication" ./my-project --content all
+```
+
+Use `csp find-related` to discover code similar to a known location (pass `filePath` and `line` from a prior search result):
+
+```bash
+csp find-related src/auth.ts 42 ./my-project
+```
+
+Like search, `find-related` also accepts an `--index` argument.
+
+`path` defaults to the current directory when omitted; git URLs are accepted.
+
+If `csp` is not on `$PATH`, use `bunx @pleaseai/csp` in its place.
+
+### Workflow
+
+1. Index the repo using `csp index -o cached_index`.
+2. Start with `csp search` to find relevant chunks. Pass the index to achieve results faster.
+3. Use `--content docs` for documentation, `--content config` for config files, or `--content all` for everything.
+4. Inspect full files only when the returned chunk does not give enough context.
+5. Optionally use `csp find-related` with a promising result's `filePath` and `line` to discover related implementations.
+6. Use grep only when you need exhaustive literal matches or quick confirmation of an exact string.
diff --git a/src/agents/copilot.md b/src/agents/copilot.md
new file mode 100644
index 0000000..238afdd
--- /dev/null
+++ b/src/agents/copilot.md
@@ -0,0 +1,56 @@
+---
+name: csp-search
+description: Code search agent for exploring any codebase. Use for finding code by intent, locating implementations, understanding how something works, or discovering related code. Prefer over Grep/Glob/Read for any semantic or exploratory question.
+tools: Bash, Read
+---
+
+Use `csp search` to find code by describing what it does or naming a symbol/identifier, instead of grep:
+
+```bash
+csp search "authentication flow" ./my-project
+csp search "save_pretrained" ./my-project
+csp search "save model to disk" ./my-project --top-k 10
+```
+
+If you anticipate doing more than one search, use `csp index` to create an index.
+
+```bash
+csp index ./my-project -o my_index
+```
+
+You can then reuse this index later on:
+
+```bash
+csp search "save_pretrained" --index my_index
+```
+
+An index is not automatically updated, so if the code changes significantly, reindex. If you notice stale results while resolving searches to files, reindex.
+
+Use `--content docs` to search documentation and prose, `--content config` for config files (yaml, toml, etc.), or `--content all` to search code, docs, and config:
+
+```bash
+csp search "deployment guide" ./my-project --content docs
+csp search "database host port" ./my-project --content config
+csp search "authentication" ./my-project --content all
+```
+
+Use `csp find-related` to discover code similar to a known location (pass `filePath` and `line` from a prior search result):
+
+```bash
+csp find-related src/auth.ts 42 ./my-project
+```
+
+Like search, `find-related` also accepts an `--index` argument.
+
+`path` defaults to the current directory when omitted; git URLs are accepted.
+
+If `csp` is not on `$PATH`, use `bunx @pleaseai/csp` in its place.
+
+### Workflow
+
+1. Index the repo using `csp index -o cached_index`.
+2. Start with `csp search` to find relevant chunks. Pass the index to achieve results faster.
+3. Use `--content docs` for documentation, `--content config` for config files, or `--content all` for everything.
+4. Inspect full files only when the returned chunk does not give enough context.
+5. Optionally use `csp find-related` with a promising result's `filePath` and `line` to discover related implementations.
+6. Use grep only when you need exhaustive literal matches or quick confirmation of an exact string.
diff --git a/src/agents/cursor.md b/src/agents/cursor.md
new file mode 100644
index 0000000..23e85d9
--- /dev/null
+++ b/src/agents/cursor.md
@@ -0,0 +1,55 @@
+---
+name: csp-search
+description: Code search agent for exploring any codebase. Use for finding code by intent, locating implementations, understanding how something works, or discovering related code. Prefer over Bash/Read for any semantic or exploratory question.
+---
+
+Use `csp search` to find code by describing what it does or naming a symbol/identifier, instead of grep:
+
+```bash
+csp search "authentication flow" ./my-project
+csp search "save_pretrained" ./my-project
+csp search "save model to disk" ./my-project --top-k 10
+```
+
+If you anticipate doing more than one search, use `csp index` to create an index.
+
+```bash
+csp index ./my-project -o my_index
+```
+
+You can then reuse this index later on:
+
+```bash
+csp search "save_pretrained" --index my_index
+```
+
+An index is not automatically updated, so if the code changes significantly, reindex. If you notice stale results while resolving searches to files, reindex.
+
+Use `--content docs` to search documentation and prose, `--content config` for config files (yaml, toml, etc.), or `--content all` to search code, docs, and config:
+
+```bash
+csp search "deployment guide" ./my-project --content docs
+csp search "database host port" ./my-project --content config
+csp search "authentication" ./my-project --content all
+```
+
+Use `csp find-related` to discover code similar to a known location (pass `filePath` and `line` from a prior search result):
+
+```bash
+csp find-related src/auth.ts 42 ./my-project
+```
+
+Like search, `find-related` also accepts an `--index` argument.
+
+`path` defaults to the current directory when omitted; git URLs are accepted.
+
+If `csp` is not on `$PATH`, use `bunx @pleaseai/csp` in its place.
+
+### Workflow
+
+1. Index the repo using `csp index -o cached_index`.
+2. Start with `csp search` to find relevant chunks. Pass the index to achieve results faster.
+3. Use `--content docs` for documentation, `--content config` for config files, or `--content all` for everything.
+4. Inspect full files only when the returned chunk does not give enough context.
+5. Optionally use `csp find-related` with a promising result's `filePath` and `line` to discover related implementations.
+6. Use grep only when you need exhaustive literal matches or quick confirmation of an exact string.
diff --git a/src/agents/gemini.md b/src/agents/gemini.md
new file mode 100644
index 0000000..9436d1a
--- /dev/null
+++ b/src/agents/gemini.md
@@ -0,0 +1,58 @@
+---
+name: csp-search
+description: Code search agent for exploring any codebase. Use for finding code by intent, locating implementations, understanding how something works, or discovering related code. Prefer over run_shell_command/read_file for any semantic or exploratory question.
+tools:
+  - run_shell_command
+  - read_file
+---
+
+Use `csp search` to find code by describing what it does or naming a symbol/identifier, instead of grep:
+
+```bash
+csp search "authentication flow" ./my-project
+csp search "save_pretrained" ./my-project
+csp search "save model to disk" ./my-project --top-k 10
+```
+
+If you anticipate doing more than one search, use `csp index` to create an index.
+
+```bash
+csp index ./my-project -o my_index
+```
+
+You can then reuse this index later on:
+
+```bash
+csp search "save_pretrained" --index my_index
+```
+
+An index is not automatically updated, so if the code changes significantly, reindex. If you notice stale results while resolving searches to files, reindex.
+
+Use `--content docs` to search documentation and prose, `--content config` for config files (yaml, toml, etc.), or `--content all` to search code, docs, and config:
+
+```bash
+csp search "deployment guide" ./my-project --content docs
+csp search "database host port" ./my-project --content config
+csp search "authentication" ./my-project --content all
+```
+
+Use `csp find-related` to discover code similar to a known location (pass `filePath` and `line` from a prior search result):
+
+```bash
+csp find-related src/auth.ts 42 ./my-project
+```
+
+Like search, `find-related` also accepts an `--index` argument.
+
+`path` defaults to the current directory when omitted; git URLs are accepted.
+
+If `csp` is not on `$PATH`, use `bunx @pleaseai/csp` in its place.
+
+### Workflow
+
+1. Index the repo using `csp index -o cached_index`.
+2. Start with `csp search` to find relevant chunks. Pass the index to achieve results faster.
+3. Use `--content docs` for documentation, `--content config` for config files, or `--content all` for everything.
+4. Inspect full files only when the returned chunk does not give enough context.
+5. Optionally use `csp find-related` with a promising result's `filePath` and `line` to discover related implementations.
+6. Use grep only when you need exhaustive literal matches or quick confirmation of an exact string.
diff --git a/src/agents/kiro.md b/src/agents/kiro.md
new file mode 100644
index 0000000..01e0df1
--- /dev/null
+++ b/src/agents/kiro.md
@@ -0,0 +1,58 @@
+---
+name: csp-search
+description: Code search agent for exploring any codebase. Use for finding code by intent, locating implementations, understanding how something works, or discovering related code. Prefer over shell/read tools for any semantic or exploratory question.
+tools:
+  - shell
+  - read
+---
+
+Use `csp search` to find code by describing what it does or naming a symbol/identifier, instead of grep:
+
+```bash
+csp search "authentication flow" ./my-project
+csp search "save_pretrained" ./my-project
+csp search "save model to disk" ./my-project --top-k 10
+```
+
+If you anticipate doing more than one search, use `csp index` to create an index.
+
+```bash
+csp index ./my-project -o my_index
+```
+
+You can then reuse this index later on:
+
+```bash
+csp search "save_pretrained" --index my_index
+```
+
+An index is not automatically updated, so if the code changes significantly, reindex. If you notice stale results while resolving searches to files, reindex.
+
+Use `--content docs` to search documentation and prose, `--content config` for config files (yaml, toml, etc.), or `--content all` to search code, docs, and config:
+
+```bash
+csp search "deployment guide" ./my-project --content docs
+csp search "database host port" ./my-project --content config
+csp search "authentication" ./my-project --content all
+```
+
+Use `csp find-related` to discover code similar to a known location (pass `filePath` and `line` from a prior search result):
+
+```bash
+csp find-related src/auth.ts 42 ./my-project
+```
+
+Like search, `find-related` also accepts an `--index` argument.
+
+`path` defaults to the current directory when omitted; git URLs are accepted.
+
+If `csp` is not on `$PATH`, use `bunx @pleaseai/csp` in its place.
+
+### Workflow
+
+1. Index the repo using `csp index -o cached_index`.
+2. Start with `csp search` to find relevant chunks. Pass the index to achieve results faster.
+3. Use `--content docs` for documentation, `--content config` for config files, or `--content all` for everything.
+4. Inspect full files only when the returned chunk does not give enough context.
+5. Optionally use `csp find-related` with a promising result's `filePath` and `line` to discover related implementations.
+6. Use grep only when you need exhaustive literal matches or quick confirmation of an exact string.
diff --git a/src/agents/opencode.md b/src/agents/opencode.md
new file mode 100644
index 0000000..8a5abc0
--- /dev/null
+++ b/src/agents/opencode.md
@@ -0,0 +1,59 @@
+---
+name: csp-search
+description: Code search agent for exploring any codebase. Use for finding code by intent, locating implementations, understanding how something works, or discovering related code. Prefer over Bash/Read for any semantic or exploratory question.
+mode: subagent
+permission:
+  bash: allow
+  read: allow
+---
+
+Use `csp search` to find code by describing what it does or naming a symbol/identifier, instead of grep:
+
+```bash
+csp search "authentication flow" ./my-project
+csp search "save_pretrained" ./my-project
+csp search "save model to disk" ./my-project --top-k 10
+```
+
+If you anticipate doing more than one search, use `csp index` to create an index.
+
+```bash
+csp index ./my-project -o my_index
+```
+
+You can then reuse this index later on:
+
+```bash
+csp search "save_pretrained" --index my_index
+```
+
+An index is not automatically updated, so if the code changes significantly, reindex. If you notice stale results while resolving searches to files, reindex.
+
+Use `--content docs` to search documentation and prose, `--content config` for config files (yaml, toml, etc.), or `--content all` to search code, docs, and config:
+
+```bash
+csp search "deployment guide" ./my-project --content docs
+csp search "database host port" ./my-project --content config
+csp search "authentication" ./my-project --content all
+```
+
+Use `csp find-related` to discover code similar to a known location (pass `filePath` and `line` from a prior search result):
+
+```bash
+csp find-related src/auth.ts 42 ./my-project
+```
+
+Like search, `find-related` also accepts an `--index` argument.
+
+`path` defaults to the current directory when omitted; git URLs are accepted.
+
+If `csp` is not on `$PATH`, use `bunx @pleaseai/csp` in its place.
+
+### Workflow
+
+1. Index the repo using `csp index -o cached_index`.
+2. Start with `csp search` to find relevant chunks. Pass the index to achieve results faster.
+3. Use `--content docs` for documentation, `--content config` for config files, or `--content all` for everything.
+4. Inspect full files only when the returned chunk does not give enough context.
+5. Optionally use `csp find-related` with a promising result's `filePath` and `line` to discover related implementations.
+6. Use grep only when you need exhaustive literal matches or quick confirmation of an exact string.
diff --git a/src/chunking/.gitkeep b/src/chunking/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/src/indexing/.gitkeep b/src/indexing/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/src/mcp/.gitkeep b/src/mcp/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/src/ranking/.gitkeep b/src/ranking/.gitkeep
new file mode 100644
index 0000000..e69de29