encode

star 12.4k

Translate constraint problems into SMT-LIB2 or Z3 Python API code. Handles common problem classes including scheduling, graph coloring, arithmetic puzzles, and verification conditions.

Z3Prover By Z3Prover schedule Updated 3/11/2026

name: encode description: Translate constraint problems into SMT-LIB2 or Z3 Python API code. Handles common problem classes including scheduling, graph coloring, arithmetic puzzles, and verification conditions.

Given a problem description (natural language, pseudocode, or a partial formulation), produce a complete, syntactically valid SMT-LIB2 encoding or Z3 Python script. The encoding should declare all variables, assert all constraints, and include the appropriate check-sat / get-model commands.

Step 1: Identify the problem class

Action: Determine the SMT theory and variable sorts required by the problem description.

Expectation: A clear mapping from the problem to one of the supported theories (LIA, LRA, QF_BV, etc.).

Result: If the theory is identified, proceed to Step 2. If the problem spans multiple theories, select the appropriate combined logic.

Problem class Theory Typical sorts
Integer arithmetic LIA / NIA Int
Real arithmetic LRA / NRA Real
Bitvector operations QF_BV (_ BitVec N)
Arrays and maps QF_AX (Array Int Int)
Strings and regex QF_S String, RegLan
Uninterpreted functions QF_UF custom sorts
Mixed theories AUFLIA, etc. combination

Step 2: Generate the encoding

Action: Invoke encode.py with the problem description and desired output format.

Expectation: The script produces a complete SMT-LIB2 file or Z3 Python script with all declarations, constraints, and check-sat commands.

Result: For smtlib2 format: pass the output to solve. For python format: execute the script directly. Proceed to Step 3 for validation.

python3 scripts/encode.py --problem "Find integers x, y such that x^2 + y^2 = 25 and x > 0" --format smtlib2
python3 scripts/encode.py --problem "Schedule 4 tasks on 2 machines minimizing makespan" --format python

Step 3: Validate the encoding

Action: The script runs a syntax check by piping the output through z3 -in in parse-only mode.

Expectation: No parse errors. If errors occur, the offending line is reported.

Result: On success: the encoding is ready for solve, prove, or optimize. On parse error: fix the reported line and re-run.

Parameters

Parameter Type Required Default Description
problem string yes problem description
format string no smtlib2 output format: smtlib2 or python
output path no stdout write to file instead of stdout
validate flag no on run syntax check on the output
debug flag no off verbose tracing
db path no .z3-agent/z3agent.db logging database
Install via CLI
npx skills add https://github.com/Z3Prover/z3 --skill encode
Repository Details
star Stars 12,359
call_split Forks 1,667
navigation Branch main
article Path SKILL.md
More from Creator