@@ -0,0 +1,5 @@
+{
+  "enabledPlugins": {
+    "commit@cc-marketplace": true
+  }
+}
@@ -0,0 +1,208 @@
+# Copilot Instructions for Stringy
+
+## Project Overview
+
+Stringy is a **smarter strings tool** for extracting meaningful strings from ELF, PE, and Mach-O binaries using format-specific knowledge and semantic classification. Unlike the standard `strings` command, Stringy is data-structure aware, section-aware, and semantically intelligent.
+
+## Architecture & Data Flow
+
+```text
+Binary -> Format Detection (goblin) -> Container Parsing -> String Extraction -> Deduplication -> Classification -> Ranking -> Output
+```
+
+### Module Organization
+
+- **`container/`** \[COMPLETE\]: Format detection (ELF/PE/Mach-O), section analysis, imports/exports via `goblin`
+- **`extraction/`** \[COMPLETE\]: ASCII/UTF-8/UTF-16 string extraction, deduplication, PE resources
+- **`classification/`** \[PARTIAL\]: Semantic tagging (URLs, IPs, domains, paths, GUIDs, etc.)
+- **`output/`** \[PLANNED\]: JSON/human-readable/YARA-friendly formatting
+- **`types/`** \[COMPLETE\]: Core data structures (`FoundString`, `ContainerInfo`, etc.), error handling
+
+## Critical Coding Standards
+
+### Zero Tolerance Policies
+
+- **No `unsafe` code**: `#![forbid(unsafe_code)]` enforced at package level
+- **Zero warnings**: `cargo clippy -- -D warnings` must pass (`#![deny(warnings)]` enforced)
+- **Rust 2024 Edition**: MSRV 1.85+, always use latest edition features
+- **File size limit**: Keep files \<=500-600 lines; split larger files into focused modules
+- **No blanket `#[allow]`**: Any `allow` attribute requires inline justification and cannot apply to entire files/modules
+- **Character restrictions**: Never use emojis, em-dashes, or other non-Latin characters in code or documentation. Use standard ASCII punctuation (hyphens, quotes, etc.)
+
+### Error Handling with `thiserror`
+
+Use structured errors with detailed context (see `src/types.rs`):
+
+```rust
+#[derive(Debug, Error)]
+pub enum StringyError {
+    #[error("Binary parsing error: {0}")]
+    ParseError(String),
+
+    #[error("Invalid encoding at offset {offset}")]
+    EncodingError { offset: u64 },
+}
+```
+
+Convert external errors with `From` implementations. Provide offsets, section names, and file paths in error messages.
+
+## Key Implementation Patterns
+
+### Section Weight System
+
+Container parsers assign weights (1.0-10.0) to sections based on string likelihood:
+
+```rust
+// ELF example from container/elf.rs
+".rodata" | ".rodata.str1.*" => 10.0  // Highest priority
+".comment" | ".note.*"       => 9.0   // Build info
+".data.rel.ro"               => 7.0   // Read-only data
+".data"                      => 5.0   // Writable data (lower priority)
+```
+
+**Pattern**: Use match expressions with fallthrough to assign weights; higher = more likely to contain meaningful strings.
+
+### String Deduplication (`extraction/dedup.rs`)
+
+Strings are grouped by `(text, encoding)` tuple in a `HashMap<(String, Encoding), Vec<StringOccurrence>>`:
+
+- **Preserve all occurrences**: Each occurrence captures offset, RVA, section, source, tags, score, confidence
+- **Tag merging**: Union all tags via `HashSet`, then sort
+- **Combined scoring formula**:
+  ```text
+  base_score = max(occurrence.original_score)
+  occurrence_bonus = 5 * (count - 1)
+  cross_section_bonus = 10 (if >1 unique section)
+  multi_source_bonus = 15 (if >1 unique StringSource)
+  confidence_boost = (max_confidence * 10.0) as i32
+  ```
+
+### Non-Exhaustive Structs
+
+Use `#[non_exhaustive]` for public API structs like `ContainerInfo` and provide explicit constructors (see `types.rs`):
+
+```rust
+#[non_exhaustive]
+pub struct ContainerInfo { /* fields */ }
+
+impl ContainerInfo {
+    pub fn new(format: BinaryFormat, sections: Vec<SectionInfo>, ...) -> Self { ... }
+}
+```
+
+## Testing Standards
+
+- **Snapshot testing**: Use `insta` for output verification (`tests/integration_*.rs`)
+- **Fixtures**: Binary test fixtures in `tests/fixtures/` (see `fixtures/README.md`)
+- **Integration tests**: Named `test_*.rs` or `integration_*.rs` in `tests/`
+- **Run tests**: `just test` (uses `cargo nextest`)
+
+Example pattern from `tests/integration_elf.rs`:
+
+```rust
+fn get_fixture_path(name: &str) -> PathBuf {
+    Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("tests/fixtures")
+        .join(name)
+}
+
+#[test]
+fn test_elf_import_export_extraction() {
+    let data = fs::read(&get_fixture_path("test_binary_elf")).expect("...");
+    let parser = ElfParser::new();
+    let info = parser.parse(&data).expect("...");
+    // Verify imports/exports with specific assertions
+}
+```
+
+## Development Workflow
+
+### Common Commands (`justfile`)
+
+**Setup**: `just setup` (installs rustfmt, clippy, llvm-tools-preview, mdformat)
+
+**Development**:
+
+- `just build` - Debug build
+- `just test` - Run tests with nextest
+- `just lint` - Full lint suite (rustfmt, clippy, actionlint, cspell, markdown)
+- `just check` - Pre-commit checks + lint
+- `just run <file>` - Run binary against test file
+
+**Code Quality**:
+
+- `just fmt` - Format Rust/markdown/YAML/JSON
+- `just fix` - Auto-fix clippy warnings with `--fix`
+- `just coverage` - Generate LCOV coverage report
+
+**CI Parity**: `just ci-check` (runs full CI suite locally)
+
+### Windows vs Unix
+
+The `justfile` uses OS annotations (`[windows]`/`[unix]`) for cross-platform compatibility. PowerShell on Windows, bash on Unix.
+
+## Dependencies & Crates
+
+**Core parsing**: `goblin` (ELF/PE/Mach-O), `pelite` (PE resources)\
+**CLI**: `clap` with derive macros\
+**Error handling**: `thiserror`\
+**Serialization**: `serde`, `serde_json`\
+**Regex**: `regex` for classification\
+**Testing**: `insta` (snapshots), `criterion` (benchmarks), `tempfile`
+
+## Import Conventions
+
+- Re-export commonly used types in `lib.rs` for ergonomic imports
+- Import from `stringy::extraction` or `stringy::types`, not deeply nested paths
+- Within `extraction/mod.rs`, do NOT import locally-defined types; downstream code imports from `stringy::extraction`
+
+## What NOT to Do
+
+- Don't use `async` (this is a synchronous CLI tool)
+- Don't add `unsafe` blocks (forbidden)
+- Don't ignore clippy warnings (they're errors)
+- Don't create files >600 lines without splitting
+- Don't use blanket `#[allow]` on modules/files
+- Don't guess at section weights (refer to existing parsers in `container/`)
+
+## Current Implementation Status
+
+**Complete**:
+
+- ELF/PE/Mach-O format detection and parsing
+- ASCII, UTF-8, UTF-16LE/BE string extraction
+- PE resource string extraction (VERSIONINFO, STRINGTABLE, MANIFEST)
+- String deduplication with occurrence tracking
+- IPv4/IPv6, URL, domain classification
+
+**In Progress**:
+
+- Full semantic classification suite (GUIDs, paths, format strings, Base64)
+- Ranking/scoring algorithm implementation
+- CLI (`main.rs` is placeholder)
+- Output formatters (JSON, YARA-friendly, human-readable)
+
+## Quick Reference Examples
+
+**Adding a new section weight** (in `container/elf.rs`, `pe.rs`, or `macho.rs`):
+
+```rust
+let weight = match section_name {
+    ".mydata" => 8.0,  // New section type
+    _ => existing_match_arms
+};
+```
+
+**Extracting strings from a section**:
+
+```rust
+use stringy::extraction::{extract_ascii_strings, AsciiExtractionConfig};
+let config = AsciiExtractionConfig { min_length: 4, max_length: 1024 };
+let strings = extract_ascii_strings(&section_data, &config);
+```
+
+**Adding a semantic tag**:
+
+1. Add variant to `Tag` enum in `types.rs`
+2. Implement pattern matching in `classification/semantic.rs`
+3. Update deduplication tag merging if needed
@@ -68,6 +68,21 @@ jobs:
       - name: Run clippy (all features)
         run: cargo clippy --all-targets --all-features -- -D warnings
 
+  # MSRV (Minimum Supported Rust Version) check
+  msrv:
+    runs-on: ubuntu-latest
+    needs: changes
+    if: needs.changes.outputs.rust == 'true'
+    steps:
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@1.91.0
+
+      - name: Cache Rust dependencies
+        uses: Swatinem/rust-cache@v2
+
+      - name: Check MSRV compliance
+        run: cargo check --all-features
+
   test:
     runs-on: ubuntu-latest
     needs: changes
-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +{
 +  "enabledPlugins": {
 +    "commit@cc-marketplace": true
 +  }
 +}