Diff tool + C, C++ and Ruby extractors improvements

README.md

@@ -37,7 +37,7 @@ Cursor (add to `mcp.json`):
 
 Done. Your agent now has a precise structural map of your code. For configuration options, multi-repo setup, and what to ask next, see [Quick start](#quick-start) below.
 
-**Supported languages:** Go · JavaScript · TypeScript · Python · Java · Kotlin · Swift · Ruby · C++ · PHP · Vue · Svelte · OpenAPI — with framework awareness (Next.js, Nuxt, SvelteKit, FastAPI, Django, Spring, Rails, Laravel, Symfony, SwiftUI, Jetpack Compose, WordPress, …)
+**Supported languages:** Go · JavaScript · TypeScript · Python · Java · Kotlin · Swift · Ruby · C · C++ · PHP · Vue · Svelte · OpenAPI — with framework awareness (Next.js, Nuxt, SvelteKit, FastAPI, Django, Spring, Rails, Laravel, Symfony, SwiftUI, Jetpack Compose, WordPress, …)
 
 ---
 
@@ -84,7 +84,7 @@ For the full mental model and internals, see **[ARCHITECTURE.md](ARCHITECTURE.md
 
 ## The tools (and how they work together)
 
-The workflow is simple: **generate the snapshot once, then ask.** These aren't text lookups — each tool *computes over the graph*: `traverse` walks reachability, `find_path` finds the shortest chain between two points, `impact_analysis` takes the transitive reverse closure. After the snapshot, your agent has nine tools on top of the graph:
+The workflow is simple: **generate the snapshot once, then ask.** These aren't text lookups — each tool *computes over the graph*: `traverse` walks reachability, `find_path` finds the shortest chain between two points, `impact_analysis` takes the transitive reverse closure. After the snapshot, your agent has these tools on top of the graph:
 
 | Tool | The question it answers |
 |------|-------------------------|
@@ -97,9 +97,13 @@ The workflow is simple: **generate the snapshot once, then ask.** These aren't t
 | `find_path` | "How does A reach B?" The call or dependency chain between two points. |
 | **`impact_analysis`** | **"If I change X, what breaks?"** The blast radius of a change. |
 | `coverage_report` | "Which cross-repo edges did enola resolve vs. miss?" Tell a genuine leaf service from a coverage gap. |
+| `set_baseline` | "Remember the architecture as it is now." Pin a baseline before you start editing. |
+| **`diff_snapshot`** | **"What did my change actually do?"** The architectural delta vs. the baseline — new findings, new coupling, added/removed symbols. |
 
 **`impact_analysis` is the one to know.** Before a refactor, it computes the full set of code that transitively depends on what you're about to change — grouped by how many hops away it is, and aware of cross-repo dependencies. Instead of your agent *guessing* what a change might affect (and missing things), it gets the exact dependent set. That's determinism turned into a concrete payoff: safer changes, planned in the right order, the first time.
 
+**`diff_snapshot` closes the loop on the edit itself.** Where `impact_analysis` plans a change, `diff_snapshot` verifies it: pin a baseline (`set_baseline`), make your edits, re-snapshot, and ask what changed. It's a **delta, not a linter** — it reports only what *moved* (findings that newly appeared or were resolved, new/removed coupling, added/removed symbols) and stays silent about pre-existing state, so a pattern that was already there before *and* after never fires. Instead of re-reading files to confirm the agent built what it claimed, you get a deterministic answer: `generate_snapshot → set_baseline → edit → generate_snapshot → diff_snapshot`.
+
 See **[ARCHITECTURE.md](ARCHITECTURE.md)** for every tool's full parameters.
 
 ---
@@ -221,7 +225,7 @@ Working across several repos? Generate the first, then add the rest with append
 | Kotlin     | `build.gradle(.kts)` with Kotlin/Android (Compose / Hilt / Room aware) |
 | Swift      | `Package.swift`, `.xcodeproj`, `.xcworkspace` (SwiftUI / UIKit aware) |
 | Ruby       | `Gemfile` (Rails / ActiveRecord / Packwerk aware) |
-| C++        | `.cpp`/`.hpp`/… source or `CMakeLists.txt`/`Makefile` + header (header/source method merging, namespaces, templates) |
+| C / C++    | `.c`/`.h` (tree-sitter-c) or `.cpp`/`.hpp`/… (tree-sitter-cpp), or `CMakeLists.txt`/`Makefile` + header (per-fact `language`, header/source method merging, namespaces, templates) |
 | PHP        | `composer.json`, WordPress markers, or any `.php` source (WordPress / Laravel / Symfony route + outbound HTTP-client aware) |
 | OpenAPI    | any spec with an `openapi:` / `swagger:` key |
 

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/modelcontextprotocol/go-sdk v1.4.1
 	github.com/tree-sitter-grammars/tree-sitter-kotlin v1.1.0
 	github.com/tree-sitter/go-tree-sitter v0.24.0
+	github.com/tree-sitter/tree-sitter-c v0.21.5-0.20240818205408-927da1f210eb
 	github.com/tree-sitter/tree-sitter-cpp v0.22.4-0.20240818224355-b1a4e2b25148
 	github.com/tree-sitter/tree-sitter-java v0.21.1-0.20240824015150-576d8097e495
 	github.com/tree-sitter/tree-sitter-php v0.22.9-0.20240819002312-a552625b56c1