CodingThrust
diff --git a/‎.claude/CLAUDE.md‎
Lines changed: 27 additions & 16 deletions b/‎.claude/CLAUDE.md‎
Lines changed: 27 additions & 16 deletions
diff --git a/‎.claude/skills/add-model/SKILL.md‎
Lines changed: 28 additions & 11 deletions b/‎.claude/skills/add-model/SKILL.md‎
Lines changed: 28 additions & 11 deletions
@@ -44,7 +44,8 @@ make diagrams      # Generate SVG diagrams from Typst (light + dark)
 make examples      # Generate example JSON for paper
 make compare       # Generate and compare Rust mapping exports
 make jl-testdata   # Regenerate Julia parity test data (requires julia)
-make cli           # Build the pred CLI tool (release mode)
+make cli           # Build the pred CLI tool (without MCP, fast)
+make mcp           # Build the pred CLI tool with MCP server support
 make cli-demo      # Run closed-loop CLI demo (exercises all commands)
 make mcp-test      # Run MCP server tests (unit + integration)
 make run-plan      # Execute a plan with Claude autorun
@@ -64,11 +65,12 @@ make release V=x.y.z  # Tag and push a new release (CI publishes to crates.io)
 
 ### Core Modules
 - `src/models/` - Problem implementations organized by input structure:
-  - `graph/` - Problems on graphs (MIS, MaxClique, MaxCut, MinVC, MinDS, MaxMatching, MaximalIS, KColoring, TSP, SpinGlass, BicliqueCover)
-  - `formula/` - Logical formulas and circuits (SAT, k-SAT, CircuitSAT)
-  - `set/` - Set systems (MinSetCovering, MaxSetPacking)
-  - `algebraic/` - Matrices, linear systems, lattices (QUBO, ILP, CVP, BMF)
-  - `misc/` - Unique input structures (BinPacking, PaintShop, Factoring)
+  - `graph/` - Graph-input problems
+  - `formula/` - Boolean formulas and circuits
+  - `set/` - Set systems (universe + subsets)
+  - `algebraic/` - Matrices, linear systems, lattices
+  - `misc/` - Unique input structures
+  - Run `pred list` for the full catalog of problems, variants, and reductions; `pred show <name>` for details on a specific problem
 - `src/rules/` - Reduction rules + inventory registration
 - `src/solvers/` - BruteForce solver, ILP solver (feature-gated)
 - `src/traits.rs` - `Problem`, `OptimizationProblem`, `SatisfactionProblem` traits
@@ -91,7 +93,8 @@ Problem (core trait — all problems must implement)
 ├── fn dims(&self) -> Vec<usize>       // config space: [2, 2, 2] for 3 binary variables
 ├── fn evaluate(&self, config) -> Metric
 ├── fn variant() -> Vec<(&str, &str)>  // e.g., [("graph","SimpleGraph"), ("weight","i32")]
-└── fn num_variables(&self) -> usize   // default: dims().len()
+├── fn num_variables(&self) -> usize   // default: dims().len()
+└── fn problem_type() -> ProblemType   // catalog bridge: registry lookup by NAME
 
 OptimizationProblem : Problem<Metric = SolutionSize<Self::Value>> (extension for optimization)
 │
@@ -111,7 +114,7 @@ enum Direction { Maximize, Minimize }
 
 ### Key Patterns
 - `variant_params!` macro implements `Problem::variant()` — e.g., `crate::variant_params![G, W]` for two type params, `crate::variant_params![]` for none (see `src/variant.rs`)
-- `declare_variants!` proc macro registers concrete type instantiations with best-known complexity — must appear in every model file (see `src/models/graph/maximum_independent_set.rs`). Variable names in complexity strings are validated at compile time against actual getter methods.
+- `declare_variants!` proc macro registers concrete type instantiations with best-known complexity and registry-backed dynamic dispatch metadata — every entry must specify `opt` or `sat`, and one entry per problem may be marked `default` (see `src/models/graph/maximum_independent_set.rs`). Variable names in complexity strings are validated at compile time against actual getter methods.
 - Problems parameterized by graph type `G` and optionally weight type `W` (problem-dependent)
 - `ReductionResult` provides `target_problem()` and `extract_solution()`
 - `Solver::find_best()` → `Option<Vec<usize>>` for optimization problems; `Solver::find_satisfying()` → `Option<Vec<usize>>` for `Metric = bool`
@@ -142,25 +145,31 @@ impl ReduceTo<Target> for Source { ... }
 - `Expr::parse()` provides runtime parsing for cross-check tests that compare compiled vs symbolic evaluation
 
 ### Problem Names
-Problem types use explicit optimization prefixes:
-- `MaximumIndependentSet`, `MaximumClique`, `MaximumMatching`, `MaximumSetPacking`
-- `MinimumVertexCover`, `MinimumDominatingSet`, `MinimumSetCovering`
-- No prefix: `MaxCut`, `SpinGlass`, `QUBO`, `ILP`, `Satisfiability`, `KSatisfiability`, `CircuitSAT`, `Factoring`, `MaximalIS`, `PaintShop`, `BicliqueCover`, `BMF`, `KColoring`, `TravelingSalesman`
+Problem types use explicit optimization prefixes (`Maximum...`, `Minimum...`) or no prefix. Run `pred list` for the full catalog. Common aliases (e.g., `MIS` → `MaximumIndependentSet`, `MVC` → `MinimumVertexCover`) are shown in the `Aliases` column.
 
-### Problem Variant IDs
+### Problem Variants
 Reduction graph nodes use variant key-value pairs from `Problem::variant()`:
 - Base: `MaximumIndependentSet` (empty variant = defaults)
 - Graph variant: `MaximumIndependentSet {graph: "KingsSubgraph", weight: "One"}`
 - Weight variant: `MaximumIndependentSet {graph: "SimpleGraph", weight: "f64"}`
 - Default variant ranking: `SimpleGraph`, `One`, `KN` are considered default values; variants with the most default values sort first
 - Nodes come exclusively from `#[reduction]` registrations; natural edges between same-name variants are inferred from the graph/weight subtype partial order
+- Each primitive reduction is determined by the exact `(source_variant, target_variant)` endpoint pair
+- `#[reduction]` accepts only `overhead = { ... }`
+
+### Extension Points
+- New models register dynamic load/serialize/brute-force dispatch through `declare_variants!` in the model file, not by adding manual match arms in the CLI
+- Exact registry dispatch lives in `src/registry/`; alias resolution and partial/default variant resolution live in `problemreductions-cli/src/problem_name.rs`
+- `pred create` UX lives in `problemreductions-cli/src/commands/create.rs`
+- Canonical paper and CLI examples live in `src/example_db/model_builders.rs` and `src/example_db/rule_builders.rs`
 
 ## Conventions
 
 ### File Naming
 - Reduction files: `src/rules/<source>_<target>.rs` (e.g., `maximumindependentset_qubo.rs`)
 - Model files: `src/models/<category>/<name>.rs` — category is by input structure: `graph/` (graph input), `formula/` (boolean formula/circuit), `set/` (universe + subsets), `algebraic/` (matrix/linear system/lattice), `misc/` (other)
-- Example files: `examples/reduction_<source>_to_<target>.rs` (must have `pub fn run()` + `fn main() { run() }`)
+- Canonical examples: builder functions in `src/example_db/rule_builders.rs` and `src/example_db/model_builders.rs`
+- Example binaries in `examples/`: utility/export tools and pedagogical demos only (not per-reduction files)
 - Test naming: `test_<source>_to_<target>_closed_loop`
 
 ### Paper (docs/paper/reductions.typ)
@@ -194,14 +203,15 @@ See Key Patterns above for solver API signatures. Follow the reference files for
 
 ### File Organization
 
-Unit tests in `src/unit_tests/` linked via `#[path]` (see Core Modules above). Integration tests in `tests/suites/`, consolidated through `tests/main.rs`. Example tests in `tests/suites/examples.rs` using `include!` for direct invocation.
+Unit tests in `src/unit_tests/` linked via `#[path]` (see Core Modules above). Integration tests in `tests/suites/`, consolidated through `tests/main.rs`. Canonical example-db coverage lives in `src/unit_tests/example_db.rs`.
 
 ## Documentation Locations
 - `README.md` — Project overview and quickstart
 - `.claude/` — Claude Code instructions and skills
 - `docs/book/` — mdBook user documentation (built with `make doc`)
 - `docs/paper/reductions.typ` — Typst paper with problem definitions and reduction theorems
-- `examples/` — Reduction example code (also used in paper and tests)
+- `src/example_db/` — Canonical model/rule examples: `model_builders.rs`, `rule_builders.rs` (in-memory builders), `specs.rs` (per-module invariant specs), consumed by `pred create --example` and paper exports
+- `examples/` — Export utilities, graph-analysis helpers, and pedagogical demos
 
 ## Documentation Requirements
 
@@ -254,3 +264,4 @@ Overhead expressions describe how target problem size relates to source problem
 2. Check that each field (e.g., `num_vertices`, `num_edges`, `num_sets`) matches the constructed target problem
 3. Watch for common errors: universe elements mismatch (edge indices vs vertex indices), worst-case edge counts in intersection graphs (quadratic, not linear), constant factors in circuit constructions
 4. Test with concrete small instances: construct a source problem, run the reduction, and compare target sizes against the formula
+5. Ensure there is only one primitive reduction registration for each exact source/target variant pair; wrap shared helpers instead of registering duplicate endpoints
@@ -36,8 +36,10 @@ Read these first to understand the patterns:
 - **Satisfaction problem:** `src/models/formula/sat.rs`
 - **Model tests:** `src/unit_tests/models/graph/maximum_independent_set.rs`
 - **Trait definitions:** `src/traits.rs` (`Problem`, `OptimizationProblem`, `SatisfactionProblem`)
-- **CLI dispatch:** `problemreductions-cli/src/dispatch.rs`
+- **Registry dispatch boundary:** `src/registry/mod.rs`, `src/registry/variant.rs`
 - **CLI aliases:** `problemreductions-cli/src/problem_name.rs`
+- **CLI creation:** `problemreductions-cli/src/commands/create.rs`
+- **Canonical model examples:** `src/example_db/model_builders.rs`
 
 ## Step 1: Determine the category
 
@@ -92,16 +94,20 @@ Add `declare_variants!` at the bottom of the model file (after the trait impls,
 
 ```rust
 crate::declare_variants! {
-    ProblemName<SimpleGraph, i32>  => "1.1996^num_vertices",
-    ProblemName<SimpleGraph, One>  => "1.1996^num_vertices",
+    opt ProblemName<SimpleGraph, i32> => "1.1996^num_vertices",
+    default opt ProblemName<SimpleGraph, One> => "1.1996^num_vertices",
 }
 ```
 
+- Each entry must include an explicit solver kind:
+  - `opt` for optimization problems (`BruteForce::find_best`)
+  - `sat` for satisfaction problems (`BruteForce::find_satisfying`)
+- Mark exactly one concrete variant `default` when the problem has multiple registered variants
 - The complexity string references the getter method names from Step 1.5 (e.g., `num_vertices`) — variable names are validated at compile time against actual getters, so typos cause compile errors
 - One entry per supported `(graph, weight)` combination
 - The string is parsed as an `Expr` AST — supports `+`, `-`, `*`, `/`, `^`, `exp()`, `log()`, `sqrt()`
 - Use only concrete numeric values (e.g., `"1.1996^num_vertices"`, not `"(2-epsilon)^num_vertices"`)
-- A compiled `complexity_eval_fn` is auto-generated alongside the symbolic expression
+- A compiled `complexity_eval_fn` plus registry-backed load/serialize/solve dispatch metadata are auto-generated alongside the symbolic expression
 - See `src/models/graph/maximum_independent_set.rs` for the reference pattern
 
 ## Step 3: Register the model
@@ -112,13 +118,14 @@ Update these files to register the new problem type:
 2. `src/models/mod.rs` -- add to the appropriate re-export line
 3. `src/lib.rs` or `prelude` -- if the type should be in `prelude::*`, add it there
 
-## Step 4: Register in CLI
+## Step 4: Register for CLI discovery
 
-Update the CLI dispatch table so `pred` can load, solve, and serialize the new problem:
+The CLI now loads, serializes, and brute-force solves problems through the core registry. Do **not** add manual match arms in `problemreductions-cli/src/dispatch.rs`.
 
-1. **`problemreductions-cli/src/dispatch.rs`:**
-   - Add a match arm in `load_problem()` -- use `deser_opt::<T>` for optimization or `deser_sat::<T>` for satisfaction
-   - Add a match arm in `serialize_any_problem()` -- use `try_ser::<T>`
+1. **Registry-backed dispatch comes from `declare_variants!`:**
+   - Make sure every concrete variant you want the CLI to load is listed in `declare_variants!`
+   - Use the correct `opt`/`sat` marker per entry
+   - Mark the intended default variant with `default` when applicable
 
 2. **`problemreductions-cli/src/problem_name.rs`:**
    - Add a lowercase alias mapping in `resolve_alias()` (e.g., `"newproblem" => "NewProblem".to_string()`)
@@ -139,6 +146,15 @@ Update `problemreductions-cli/src/commands/create.rs` so `pred create <ProblemNa
 
 4. **Schema alignment**: The `ProblemSchemaEntry` fields should list **constructor parameters** (what the user provides), not internal derived fields. For example, if `m` and `n` are derived from a matrix, only list `matrix` and `k` in the schema.
 
+## Step 4.6: Add canonical model example to example_db
+
+Add a builder function in `src/example_db/model_builders.rs` that constructs a small, canonical instance for this model. Register it in `build_model_examples()`.
+
+This example is now the canonical source for:
+- `pred create --example <PROBLEM_SPEC>`
+- paper/example exports
+- example-db invariants tested in `src/unit_tests/example_db.rs`
+
 ## Step 5: Write unit tests
 
 Create `src/unit_tests/models/<category>/<name>.rs`:
@@ -233,12 +249,13 @@ If running standalone (not inside `make run-plan`), invoke [review-implementatio
 | Missing `#[path]` test link | Add `#[cfg(test)] #[path = "..."] mod tests;` at file bottom |
 | Wrong `dims()` | Must match the actual configuration space (e.g., `vec![2; n]` for binary) |
 | Not registering in `mod.rs` | Must update both `<category>/mod.rs` and `models/mod.rs` |
-| Forgetting `declare_variants!` | Required for variant complexity metadata used by the paper's auto-generated table |
-| Forgetting CLI dispatch | Must add match arms in `dispatch.rs` (`load_problem` + `serialize_any_problem`) |
+| Forgetting `declare_variants!` | Required for variant complexity metadata and registry-backed load/serialize/solve dispatch |
+| Wrong `declare_variants!` syntax | Every entry now needs `opt` or `sat`; one entry per problem may be marked `default` |
 | Forgetting CLI alias | Must add lowercase entry in `problem_name.rs` `resolve_alias()` |
 | Inventing short aliases | Only use well-established literature abbreviations (MIS, SAT, TSP); do NOT invent new ones |
 | Forgetting CLI create | Must add creation handler in `commands/create.rs` and flags in `cli.rs` |
 | Missing from CLI help table | Must add entry to "Flags by problem type" table in `cli.rs` `after_help` |
 | Schema lists derived fields | Schema should list constructor params, not internal fields (e.g., `matrix, k` not `matrix, m, n, k`) |
+| Missing canonical model example | Add a builder in `src/example_db/model_builders.rs` and keep it aligned with paper/example workflows |
 | Forgetting trait_consistency | Must add entry in `test_all_problems_implement_trait_correctly` (and `test_direction` for optimization) in `src/unit_tests/trait_consistency.rs` |
 | Paper example not tested | Must include `test_<name>_paper_example` that verifies the exact instance, solution, and solution count shown in the paper |