diff --git a/README.md b/README.md
index 583035515..8d6df2363 100644
--- a/README.md
+++ b/README.md
@@ -178,7 +178,7 @@ config = TemoaConfig(
     time_sequencing='seasonal_timeslices',
     input_database='tutorial_database.sqlite',
     output_database='tutorial_database.sqlite',
-    solver_name='appsi_highs',
+    solver='appsi_highs',
     output_path=output_path,
     silent=False,
 )
@@ -238,7 +238,7 @@ scenario = "tutorial"
 scenario_mode = "perfect_foresight"
 input_database = "tutorial_database.sqlite"
 output_database = "tutorial_database.sqlite"
-solver_name = "appsi_highs"
+solver = "appsi_highs"
 ```
 
 ### Configuration Options
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 49a81cce6..33c98884a 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1148,9 +1148,9 @@ pillow==12.3.0 \
     --hash=sha256:fe3cca2e4e8a592be0f269a1ca4835c25199d9f3ce815c8491048f785b0a0198 \
     --hash=sha256:ffd0c5368496f41b0944be820fcb7a838aa6e623d250b01acf2643939c3f99d7
     # via matplotlib
-pint==0.25.3 \
-    --hash=sha256:27eb25143bd5de9fcc4d5a4b484f16faf6b4615aa93ece6b3373a8c1a3c1b97d \
-    --hash=sha256:f8f5df6cf65314d74da1ade1bf96f8e3e4d0c41b51577ac53c49e7d44ca5acee
+pint==0.26.1 \
+    --hash=sha256:1bbde36eae57a5a289cd05081c6405618a5899814940752064ce351cd0204f71 \
+    --hash=sha256:e982b129415c09c63308f314ae44697d83e5c96f253bcc0d5b833fc3329eb6d4
     # via temoa
 platformdirs==4.11.7 \
     --hash=sha256:4f41487eeeeeb07f3a6625e61d9bc0ae6809f92d3386dbd74392fbb76108104d \
diff --git a/requirements.txt b/requirements.txt
index f4af38140..3da57ca78 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -557,9 +557,9 @@ pillow==12.3.0 \
     --hash=sha256:fe3cca2e4e8a592be0f269a1ca4835c25199d9f3ce815c8491048f785b0a0198 \
     --hash=sha256:ffd0c5368496f41b0944be820fcb7a838aa6e623d250b01acf2643939c3f99d7
     # via matplotlib
-pint==0.25.3 \
-    --hash=sha256:27eb25143bd5de9fcc4d5a4b484f16faf6b4615aa93ece6b3373a8c1a3c1b97d \
-    --hash=sha256:f8f5df6cf65314d74da1ade1bf96f8e3e4d0c41b51577ac53c49e7d44ca5acee
+pint==0.26.1 \
+    --hash=sha256:1bbde36eae57a5a289cd05081c6405618a5899814940752064ce351cd0204f71 \
+    --hash=sha256:e982b129415c09c63308f314ae44697d83e5c96f253bcc0d5b833fc3329eb6d4
     # via temoa
 platformdirs==4.11.7 \
     --hash=sha256:4f41487eeeeeb07f3a6625e61d9bc0ae6809f92d3386dbd74392fbb76108104d \
diff --git a/temoa/_internal/run_actions.py b/temoa/_internal/run_actions.py
index dcdc01bd5..d586dfa9a 100644
--- a/temoa/_internal/run_actions.py
+++ b/temoa/_internal/run_actions.py
@@ -3,12 +3,13 @@
 """
 
 import sqlite3
-from collections.abc import Generator, Iterable
+from collections.abc import Generator, Iterable, Mapping
 from contextlib import contextmanager
 from logging import getLogger
 from pathlib import Path
 from sys import version_info
 from time import perf_counter
+from typing import Any
 
 from pyomo.environ import (
     Constraint,
@@ -25,6 +26,7 @@
 from temoa._internal.table_writer import TableWriter
 from temoa.core.config import TemoaConfig
 from temoa.core.model import TemoaModel
+from temoa.core.solver_spec import DEFAULT_SOLVER_OPTIONS
 from temoa.data_processing.db_to_excel import make_excel
 
 logger = getLogger(__name__)
@@ -174,6 +176,7 @@ def solve_instance(
     solver_name: str,
     silent: bool = False,
     solver_suffixes: Iterable[str] | None = None,
+    solver_options: Mapping[str, Any] | None = None,
 ) -> tuple[TemoaModel, SolverResults]:
     """
     Solve the instance and return a loaded instance
@@ -181,6 +184,8 @@ def solve_instance(
     'duals' is supported in the Temoa Framework.  Some solvers may not support duals.
     :param silent: Run silently
     :param solver_name: The name of the solver to request from the SolverFactory
+    :param solver_options: options to set on the solver (see resolve_solver_options).  If None,
+    the Temoa defaults for the solver are used
     :param instance: the instance to solve
     :return: loaded instance
     """
@@ -202,28 +207,11 @@ def solve_instance(
     if solver_name == 'neos':
         raise NotImplementedError('Neos based solve is not currently supported')
 
-    # Solver Configuration
-    if solver_name == 'cbc':
-        pass
-
-    elif solver_name == 'cplex':
-        # Note: these parameter values match mip-dev / PyPSA
-        # (see: https://pypsa-eur.readthedocs.io/en/latest/configuration.html)
-        optimizer.options['lpmethod'] = 4  # barrier
-        optimizer.options['solutiontype'] = 2  # non basic solution, ie no crossover
-        optimizer.options['barrier convergetol'] = 1.0e-3
-        optimizer.options['feasopt tolerance'] = 1.0e-4
-
-    elif solver_name == 'gurobi':
-        # Note: these parameter values match mip-dev / PyPSA (see: https://pypsa-eur.readthedocs.io/en/latest/configuration.html)
-        optimizer.options['Method'] = 2  # barrier
-        optimizer.options['Crossover'] = 0  # non basic solution, ie no crossover
-        optimizer.options['BarConvTol'] = 1.0e-3
-        optimizer.options['FeasibilityTol'] = 1.0e-4
-        optimizer.options['BarOrder'] = -1  # auto ordering; 2-4x faster than AMD on large models
-
-    elif solver_name == 'appsi_highs':
-        pass
+    # Solver Configuration (defaults live in temoa.core.solver_spec.DEFAULT_SOLVER_OPTIONS)
+    if solver_options is None:
+        solver_options = DEFAULT_SOLVER_OPTIONS.get(solver_name, {})
+    for option, option_value in solver_options.items():
+        optimizer.options[option] = option_value
 
     # Suffix Handling
     solver_suffixes_list: list[str] = []
diff --git a/temoa/_internal/temoa_sequencer.py b/temoa/_internal/temoa_sequencer.py
index bd44044e3..d781aad1b 100644
--- a/temoa/_internal/temoa_sequencer.py
+++ b/temoa/_internal/temoa_sequencer.py
@@ -27,6 +27,7 @@
 from temoa.core.config import TemoaConfig
 from temoa.core.model import TemoaModel
 from temoa.core.modes import TemoaMode
+from temoa.core.solver_spec import resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 from temoa.extensions.method_of_morris.morris_sequencer import MorrisSequencer
 from temoa.extensions.modeling_to_generate_alternatives.mga_sequencer import MgaSequencer
@@ -254,6 +255,7 @@ def _run_perfect_foresight(self) -> None:
                 self.config.solver_name,
                 silent=self.config.silent,
                 solver_suffixes=suffixes,
+                solver_options=resolve_solver_options(self.config.solver),
             )
             good_solve, msg = check_solve_status(self.pf_results)
             if not good_solve:
diff --git a/temoa/core/config.py b/temoa/core/config.py
index 3e68c9225..173b296b7 100644
--- a/temoa/core/config.py
+++ b/temoa/core/config.py
@@ -1,10 +1,14 @@
 import shutil
 import sys
 import tomllib
+import warnings
+from collections.abc import Mapping
 from logging import getLogger
 from pathlib import Path
+from typing import Any
 
 from temoa.core.modes import TemoaMode
+from temoa.core.solver_spec import SolverSpec, redact_solver_options
 from temoa.extensions.framework import normalize_extension_ids, resolve_extension_specs
 
 logger = getLogger(__name__)
@@ -42,7 +46,7 @@ def __init__(
         input_database: Path,
         output_database: Path,
         output_path: Path,
-        solver_name: str,
+        solver_name: str | None = None,
         neos: bool = False,
         save_excel: bool = False,
         save_duals: bool = False,
@@ -73,6 +77,7 @@ def __init__(
         output_threshold_cost: float | None = None,
         sqlite: dict[str, object] | None = None,
         extensions: list[str] | tuple[str, ...] | None = None,
+        solver: str | Mapping[str, Any] | SolverSpec | None = None,
     ):
         if '-' in scenario:
             raise ValueError(
@@ -129,7 +134,20 @@ def __init__(
         self.neos = neos
         if self.neos:
             raise NotImplementedError('Neos is currently not supported.')
-        self.solver_name = solver_name
+
+        # Validate solver input
+        if solver_name is not None:
+            if solver is not None:
+                raise ValueError("Specify either 'solver' or 'solver_name', not both")
+            warnings.warn(
+                "The 'solver_name' argument is deprecated, use 'solver' instead",
+                DeprecationWarning,
+                stacklevel=2,
+            )
+            solver = solver_name
+        if solver is None:
+            raise SolverNotAvailableError('No solver specified in the configuration.')
+        self.solver = SolverSpec.parse(solver)
 
         self.save_excel = save_excel
         self.save_duals = save_duals
@@ -230,6 +248,17 @@ def __init__(
                 if not self.silent:
                     sys.stderr.write('Warning: ' + msg)
 
+    @property
+    def solver_name(self) -> str:
+        """The name of the selected solver (shorthand for self.solver.name)"""
+        return self.solver.name
+
+    @solver_name.setter
+    def solver_name(self, value: str) -> None:
+        # retained for backward compatibility.  Changing solvers drops any configured options,
+        # as they are specific to the previous solver
+        self.solver = SolverSpec.parse(value)
+
     @staticmethod
     def _check_solver_availability(solver_name: str) -> tuple[bool, str | None]:
         """
@@ -282,27 +311,41 @@ def build_config(config_file: Path, output_path: Path, silent: bool = False) ->
             data = tomllib.load(f)
 
         if 'solver_name' in data:
-            is_available, location = TemoaConfig._check_solver_availability(data['solver_name'])
-            if not is_available:
-                error_message = (
-                    f"The specified solver '{data['solver_name']}' was not found.\n"
-                    'Please ensure the solver is installed and accessible.\n'
+            if 'solver' in data:
+                raise ValueError(
+                    "Config specifies both 'solver' and 'solver_name'.  Use only 'solver' "
+                    "('solver_name' is deprecated)."
                 )
-                if data['solver_name'].lower() in SOLVER_DOC_LINKS:
-                    link = SOLVER_DOC_LINKS[data['solver_name'].lower()]
-                    error_message += f'For installation instructions, refer to: {link}\n'
-                else:
-                    error_message += (
-                        "Refer to the solver's official documentation for "
-                        'installation instructions.'
-                    )
-                raise SolverNotAvailableError(error_message)
+            logger.warning(
+                "The 'solver_name' config key is deprecated and will be removed in a future "
+                'release.  Replace it with: solver = "%s"',
+                data['solver_name'],
+            )
+            data['solver'] = data.pop('solver_name')
+
+        if 'solver' not in data:
+            raise SolverNotAvailableError('No solver name specified in the configuration.')
+        solver = SolverSpec.parse(data['solver'])
+        data['solver'] = solver
+
+        is_available, location = TemoaConfig._check_solver_availability(solver.name)
+        if not is_available:
+            error_message = (
+                f"The specified solver '{solver.name}' was not found.\n"
+                'Please ensure the solver is installed and accessible.\n'
+            )
+            if solver.name.lower() in SOLVER_DOC_LINKS:
+                link = SOLVER_DOC_LINKS[solver.name.lower()]
+                error_message += f'For installation instructions, refer to: {link}\n'
             else:
-                logger.info('Using solver: %s (%s)', data['solver_name'], location)
+                error_message += (
+                    "Refer to the solver's official documentation for installation instructions."
+                )
+            raise SolverNotAvailableError(error_message)
         else:
-            raise SolverNotAvailableError('No solver name specified in the configuration.')
+            logger.info('Using solver: %s (%s)', solver.name, location)
 
-        if data.get('solver_name') == 'appsi_highs' and data.get('save_duals', False):
+        if solver.name == 'appsi_highs' and data.get('save_duals', False):
             raise ValueError(
                 'save_duals is not supported with appsi_highs (it does not expose duals via the '
                 'APPSI interface). Disable save_duals or choose a different solver.'
@@ -354,6 +397,9 @@ def __repr__(self) -> str:
 
         msg += spacer
         msg += '{:>{}s}: {}\n'.format('Selected solver', width, self.solver_name)
+        msg += '{:>{}s}: {}\n'.format(
+            'Solver options', width, redact_solver_options(self.solver.options)
+        )
         msg += '{:>{}s}: {}\n'.format('NEOS status', width, self.neos)
 
         msg += spacer
diff --git a/temoa/core/solver_spec.py b/temoa/core/solver_spec.py
new file mode 100644
index 000000000..800810228
--- /dev/null
+++ b/temoa/core/solver_spec.py
@@ -0,0 +1,107 @@
+"""
+Solver selection and option resolution.
+
+The config accepts ``solver`` as either a plain solver name or a table with a ``name`` and a
+passthrough ``options`` table.  Options that reach the solver are layered as:
+
+    DEFAULT_SOLVER_OPTIONS  <  [solver.options]  <  extension-specific options (MGA, MC, ...)
+
+Any solver name known to pyomo's SolverFactory is accepted.  Solvers without an entry in
+DEFAULT_SOLVER_OPTIONS simply get no Temoa defaults.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Mapping
+from dataclasses import dataclass, field
+from typing import Any
+
+# Note: these parameter values match mip-dev / PyPSA
+# (see: https://pypsa-eur.readthedocs.io/en/latest/configuration.html)
+DEFAULT_SOLVER_OPTIONS: dict[str, dict[str, Any]] = {
+    'cplex': {
+        'lpmethod': 4,  # barrier
+        'solutiontype': 2,  # non basic solution, ie no crossover
+        'barrier convergetol': 1.0e-3,
+        'feasopt tolerance': 1.0e-4,
+    },
+    'gurobi': {
+        'Method': 2,  # barrier
+        'Crossover': 0,  # non basic solution, ie no crossover
+        'BarConvTol': 1.0e-3,
+        'FeasibilityTol': 1.0e-4,
+        'BarOrder': -1,  # auto ordering; 2-4x faster than AMD on large models
+    },
+}
+
+
+@dataclass(frozen=True, slots=True)
+class SolverSpec:
+    """A solver name plus the user-supplied options from the config (defaults excluded)."""
+
+    name: str
+    options: Mapping[str, Any] = field(default_factory=dict)
+
+    @classmethod
+    def parse(cls, raw: str | Mapping[str, Any] | SolverSpec) -> SolverSpec:
+        """
+        Build a SolverSpec from a solver name, a {'name': ..., 'options': {...}} mapping, or an
+        existing SolverSpec
+        """
+        if isinstance(raw, SolverSpec):
+            return raw
+        if isinstance(raw, str):
+            if not raw:
+                raise ValueError('Solver name must not be empty')
+            return cls(raw)
+        if isinstance(raw, Mapping):
+            unknown = set(raw) - {'name', 'options'}
+            if unknown:
+                raise ValueError(
+                    f'Unrecognized key(s) in solver table: {sorted(unknown)}.  Expected "name" '
+                    'and (optionally) "options".  Solver parameters belong under [solver.options]'
+                )
+            name = raw.get('name')
+            if not isinstance(name, str) or not name:
+                raise ValueError('The solver table requires a non-empty "name" entry')
+            options = raw.get('options', {})
+            if not isinstance(options, Mapping):
+                raise ValueError('The "options" entry of the solver table must be a table/dict')
+            return cls(name, dict(options))
+        raise TypeError(f'solver must be a str or a table/dict, got: {type(raw).__name__}')
+
+
+# substrings (lowercase) of option names whose values are credentials, e.g. gurobi's WLSSecret,
+# CloudSecretKey, CSAPIAccessID, ServerPassword, LicenseID
+_SENSITIVE_OPTION_MARKERS = ('secret', 'password', 'accessid', 'licenseid', 'key', 'token')
+
+
+def redact_solver_options(options: Mapping[str, Any]) -> dict[str, Any]:
+    """
+    Return a copy of the options that is safe to log or print, with credential values masked
+    """
+    return {
+        option: '***'
+        if any(marker in option.lower() for marker in _SENSITIVE_OPTION_MARKERS)
+        else option_value
+        for option, option_value in options.items()
+    }
+
+
+def resolve_solver_options(
+    spec: SolverSpec,
+    extension_options: Mapping[str, Any] | None = None,
+    *,
+    include_defaults: bool = True,
+) -> dict[str, Any]:
+    """
+    Merge the option layers that are passed to the solver
+    :param spec: the solver spec from the config
+    :param extension_options: options from an extension's own source (MGA/MC/Morris toml,
+    stochastic config), which take precedence over everything else
+    :param include_defaults: include DEFAULT_SOLVER_OPTIONS as the bottom layer.  Solve paths that
+    historically ran without Temoa defaults (MGA base solve, stochastic) turn this off.
+    :return: a new dict of solver options
+    """
+    defaults = DEFAULT_SOLVER_OPTIONS.get(spec.name, {}) if include_defaults else {}
+    return {**defaults, **spec.options, **(extension_options or {})}
diff --git a/temoa/extensions/method_of_morris/morris.py b/temoa/extensions/method_of_morris/morris.py
index 4ae1f308f..19dc114e9 100644
--- a/temoa/extensions/method_of_morris/morris.py
+++ b/temoa/extensions/method_of_morris/morris.py
@@ -16,6 +16,7 @@
 from temoa._internal import run_actions
 from temoa._internal.table_writer import TableWriter
 from temoa.core.config import TemoaConfig
+from temoa.core.solver_spec import resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 
 seed = 42
@@ -40,7 +41,11 @@ def evaluate(
 
     dp = DataPortal(data_dict={None: data})
     instance = run_actions.build_instance(loaded_portal=dp, extensions=config.extensions)
-    mdl, res = run_actions.solve_instance(instance=instance, solver_name=config.solver_name)
+    mdl, res = run_actions.solve_instance(
+        instance=instance,
+        solver_name=config.solver_name,
+        solver_options=resolve_solver_options(config.solver),
+    )
     status = run_actions.check_solve_status(res)
     if not status:
         raise RuntimeError('Bad solve during Method of Morris')
diff --git a/temoa/extensions/method_of_morris/morris_evaluate.py b/temoa/extensions/method_of_morris/morris_evaluate.py
index 9695b1406..daa3e8064 100644
--- a/temoa/extensions/method_of_morris/morris_evaluate.py
+++ b/temoa/extensions/method_of_morris/morris_evaluate.py
@@ -43,6 +43,7 @@ def evaluate(
     config: TemoaConfig,
     log_queue: Any,
     log_level: int,
+    solver_options: dict[str, Any] | None = None,
 ) -> list[float]:
     """
     Run model for params provided and return objective value and emission value
@@ -54,6 +55,7 @@ def evaluate(
     :param data: Data used to build the Data Portal
     :param i: indexing number
     :param config: The config file to pull run data from
+    :param solver_options: resolved solver options.  If None, the Temoa defaults are used
     :return: list of objective value and CO2 emission value
     """
     # get the logger configured...
@@ -80,7 +82,10 @@ def evaluate(
         extensions=config.extensions,
     )
     mdl, res = run_actions.solve_instance(
-        instance=instance, solver_name=config.solver_name, silent=True
+        instance=instance,
+        solver_name=config.solver_name,
+        silent=True,
+        solver_options=solver_options,
     )
     status = run_actions.check_solve_status(res)
     if not status:
diff --git a/temoa/extensions/method_of_morris/morris_sequencer.py b/temoa/extensions/method_of_morris/morris_sequencer.py
index 6c3d1bc76..3a5baf194 100644
--- a/temoa/extensions/method_of_morris/morris_sequencer.py
+++ b/temoa/extensions/method_of_morris/morris_sequencer.py
@@ -22,6 +22,7 @@
 from SALib.util import compute_groups_matrix, read_param_file  # type: ignore[import-untyped]
 
 from temoa._internal.table_writer import TableWriter
+from temoa.core.solver_spec import redact_solver_options, resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 from temoa.extensions.method_of_morris.morris_evaluate import evaluate
 
@@ -70,11 +71,12 @@ def __init__(self, config: TemoaConfig):
                 with open(path, 'rb') as f:
                     all_options = tomllib.load(f)
             s_options = all_options.get(self.config.solver_name, {})
-            logger.info('Using solver options: %s', s_options)
 
         except FileNotFoundError:
             logger.warning('Unable to find solver options toml file.  Using default options.')
             s_options = {}
+        self.solver_options = resolve_solver_options(self.config.solver, s_options)
+        logger.info('Using solver options: %s', redact_solver_options(self.solver_options))
 
         # output handling
         self.verbose = False  # for troubleshooting
@@ -189,7 +191,14 @@ def start(self) -> Any:
             sys.stdout.flush()
         morris_results = Parallel(n_jobs=self.num_cores)(
             delayed(evaluate)(
-                param_names, mm_samples[i, :], data, i, self.config, log_queue, log_level
+                param_names,
+                mm_samples[i, :],
+                data,
+                i,
+                self.config,
+                log_queue,
+                log_level,
+                solver_options=self.solver_options,
             )
             for i in range(0, len(mm_samples))
         )
diff --git a/temoa/extensions/modeling_to_generate_alternatives/MGA_solver_options.toml b/temoa/extensions/modeling_to_generate_alternatives/MGA_solver_options.toml
index 869a53384..2b57d00c6 100644
--- a/temoa/extensions/modeling_to_generate_alternatives/MGA_solver_options.toml
+++ b/temoa/extensions/modeling_to_generate_alternatives/MGA_solver_options.toml
@@ -1,5 +1,7 @@
 # A container for solver options
 # the top level solver name in brackets should align with the solver name in the config.toml
+# These are layered on top of Temoa's solver defaults and the config's [solver.options], and take
+# precedence over both.  (see temoa/core/solver_spec.py)
 
 num_workers = 6
 
@@ -11,6 +13,7 @@ BarConvTol = 0.01  # Relative Barrier Tolerance primal-dual
 FeasibilityTol= 1e-2  # pretty loose
 Crossover= 0  # Disabled
 TimeLimit= 18000  # 5 hrs
+BarOrder = -1  # auto ordering (gurobi default)
 
 # regarding BarConvTol:  https://www.gurobi.com/documentation/current/refman/barrier_logging.html
 # note that ref above seems to imply that FeasibilyTol is NOT used when using barrier only...?
@@ -19,6 +22,13 @@ TimeLimit= 18000  # 5 hrs
 # 'LogFile': './my_gurobi_log.log',
 # 'LPWarmStart': 2,  # pass basis
 
+[cplex]
+# CPLEX's own defaults, restating them overrides the Temoa cplex defaults for MGA workers
+lpmethod = 0  # automatic
+solutiontype = 0  # automatic
+'barrier convergetol' = 1.0e-8
+'feasopt tolerance' = 1.0e-6
+
 [cbc]
 # tbd
 
diff --git a/temoa/extensions/modeling_to_generate_alternatives/mga_sequencer.py b/temoa/extensions/modeling_to_generate_alternatives/mga_sequencer.py
index a261ba458..ebdfae220 100644
--- a/temoa/extensions/modeling_to_generate_alternatives/mga_sequencer.py
+++ b/temoa/extensions/modeling_to_generate_alternatives/mga_sequencer.py
@@ -33,6 +33,7 @@
 from temoa._internal.run_actions import build_instance
 from temoa._internal.table_writer import TableWriter
 from temoa.components.costs import total_cost_rule
+from temoa.core.solver_spec import redact_solver_options, resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 from temoa.extensions.modeling_to_generate_alternatives.manager_factory import get_manager
 from temoa.extensions.modeling_to_generate_alternatives.mga_constants import MgaAxis, MgaWeighting
@@ -93,16 +94,23 @@ def __init__(self, config: TemoaConfig):
                 with open(path, 'rb') as f:
                     all_options = tomllib.load(f)
             s_options = all_options.get(self.config.solver_name, {})
-            logger.info('Using solver options: %s', s_options)
 
         except FileNotFoundError:
             logger.warning('Unable to find solver options toml file.  Using default options.')
             s_options = {}
             all_options = {}
 
-        # get handle on solver instance
+        # get handle on solver instance.  The base solve only receives the user's
+        # [solver.options] (no Temoa defaults, no worker options) to get a more precise base cost
         self.opt = pyo.SolverFactory(self.config.solver_name)
-        self.worker_solver_options = s_options
+        for option, option_value in resolve_solver_options(
+            self.config.solver, include_defaults=False
+        ).items():
+            self.opt.options[option] = option_value
+        self.worker_solver_options = resolve_solver_options(self.config.solver, s_options)
+        logger.info(
+            'Using worker solver options: %s', redact_solver_options(self.worker_solver_options)
+        )
 
         # some defaults, etc.
         self.internal_stop = False
diff --git a/temoa/extensions/monte_carlo/MC_solver_options.toml b/temoa/extensions/monte_carlo/MC_solver_options.toml
index da91cd56e..7a7471d61 100644
--- a/temoa/extensions/monte_carlo/MC_solver_options.toml
+++ b/temoa/extensions/monte_carlo/MC_solver_options.toml
@@ -1,5 +1,7 @@
 # A container for solver options
 # the top level solver name in brackets should align with the solver name in the config.toml
+# These are layered on top of Temoa's solver defaults and the config's [solver.options], and take
+# precedence over both.  (see temoa/core/solver_spec.py)
 
 num_workers = 11
 
@@ -11,6 +13,7 @@ BarConvTol = 1.0e-2  # Relative Barrier Tolerance primal-dual
 FeasibilityTol= 1.0e-2  # pretty loose
 Crossover= 0  # Disabled
 TimeLimit= 18000  # 5 hrs
+BarOrder = -1  # auto ordering (gurobi default)
 
 # regarding BarConvTol:  https://www.gurobi.com/documentation/current/refman/barrier_logging.html
 # note that ref above seems to imply that FeasibilyTol is NOT used when using barrier only...?
@@ -19,6 +22,13 @@ TimeLimit= 18000  # 5 hrs
 # 'LogFile': './my_gurobi_log.log',
 # 'LPWarmStart': 2,  # pass basis
 
+[cplex]
+# CPLEX's own defaults, restating them overrides the Temoa cplex defaults for MC workers
+lpmethod = 0  # automatic
+solutiontype = 0  # automatic
+'barrier convergetol' = 1.0e-8
+'feasopt tolerance' = 1.0e-6
+
 [cbc]
 primalT = 1e-3
 dualT = 1e-3
diff --git a/temoa/extensions/monte_carlo/mc_sequencer.py b/temoa/extensions/monte_carlo/mc_sequencer.py
index eb99da89a..c5318e23f 100644
--- a/temoa/extensions/monte_carlo/mc_sequencer.py
+++ b/temoa/extensions/monte_carlo/mc_sequencer.py
@@ -18,6 +18,7 @@
 from typing import TYPE_CHECKING, Any, cast
 
 from temoa._internal.table_writer import TableWriter
+from temoa.core.solver_spec import redact_solver_options, resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 from temoa.extensions.monte_carlo.mc_run import MCRun, MCRunFactory
 from temoa.extensions.monte_carlo.mc_worker import MCWorker
@@ -83,7 +84,6 @@ def __init__(self, config: TemoaConfig):
                     with open(path, 'rb') as f:
                         all_options = tomllib.load(f)
             s_options = all_options.get(self.config.solver_name, {})
-            logger.info('Using solver options: %s', s_options)
 
         except FileNotFoundError:
             if options_file_path:
@@ -95,7 +95,8 @@ def __init__(self, config: TemoaConfig):
 
         # worker options pulled from file
         self.num_workers = all_options.get('num_workers', 1)
-        self.worker_solver_options = s_options
+        self.worker_solver_options = resolve_solver_options(self.config.solver, s_options)
+        logger.info('Using solver options: %s', redact_solver_options(self.worker_solver_options))
 
         # internal records
         self.solve_count = 0
diff --git a/temoa/extensions/myopic/myopic_sequencer.py b/temoa/extensions/myopic/myopic_sequencer.py
index e32ed347f..8d01c0c04 100644
--- a/temoa/extensions/myopic/myopic_sequencer.py
+++ b/temoa/extensions/myopic/myopic_sequencer.py
@@ -16,6 +16,7 @@
 from temoa._internal.table_writer import TableWriter
 from temoa.core.config import TemoaConfig
 from temoa.core.model import TemoaModel
+from temoa.core.solver_spec import resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 from temoa.data_processing.db_to_excel import make_excel
 from temoa.extensions.myopic.myopic_index import MyopicIndex
@@ -268,7 +269,10 @@ def start(self) -> None:
             if not self.config.silent and self.progress_mapper and idx:
                 self.progress_mapper.report(idx, 'solve')
             model, results = run_actions.solve_instance(
-                instance=instance, solver_name=self.config.solver_name, silent=True
+                instance=instance,
+                solver_name=self.config.solver_name,
+                silent=True,
+                solver_options=resolve_solver_options(self.config.solver),
             )
 
             optimal, status = run_actions.check_solve_status(results)
diff --git a/temoa/extensions/single_vector_mga/sv_mga_sequencer.py b/temoa/extensions/single_vector_mga/sv_mga_sequencer.py
index 543af6678..d0266c317 100644
--- a/temoa/extensions/single_vector_mga/sv_mga_sequencer.py
+++ b/temoa/extensions/single_vector_mga/sv_mga_sequencer.py
@@ -19,6 +19,7 @@
 from temoa.components.costs import total_cost_rule
 from temoa.core.config import TemoaConfig
 from temoa.core.model import TemoaModel
+from temoa.core.solver_spec import resolve_solver_options
 from temoa.data_io.hybrid_loader import HybridLoader
 from temoa.extensions.single_vector_mga.output_summary import summarize
 from temoa.model_checking.pricing_check import price_checker
@@ -100,6 +101,7 @@ def start(self) -> None:
             solver_name=self.config.solver_name,
             silent=self.config.silent,
             solver_suffixes=suffixes,
+            solver_options=resolve_solver_options(self.config.solver),
         )
         status = res.solver.termination_condition
         logger.debug('Termination condition: %s', status.name)
@@ -163,6 +165,7 @@ def start(self) -> None:
             solver_name=self.config.solver_name,
             silent=self.config.silent,
             solver_suffixes=suffixes,
+            solver_options=resolve_solver_options(self.config.solver),
         )
         status = res.solver.termination_condition
         logger.debug('Termination condition: %s', status.name)
diff --git a/temoa/extensions/stochastics/stochastic_sequencer.py b/temoa/extensions/stochastics/stochastic_sequencer.py
index 5c904ce30..195cf691a 100644
--- a/temoa/extensions/stochastics/stochastic_sequencer.py
+++ b/temoa/extensions/stochastics/stochastic_sequencer.py
@@ -5,6 +5,7 @@
 
 import pyomo.environ as pyo
 
+from temoa.core.solver_spec import resolve_solver_options
 from temoa.extensions.stochastics.stochastic_config import StochasticConfig
 
 if TYPE_CHECKING:
@@ -50,8 +51,13 @@ def start(self) -> None:
 
         from temoa.extensions.stochastics.scenario_creator import scenario_creator
 
-        # Merge solver options from stoch_config
-        solver_options = self.stoch_config.solver_options.get(self.config.solver_name, {})
+        # Merge solver options: [solver.options] < stoch_config.  Temoa defaults are excluded to
+        # preserve the behavior of stochastic runs prior to the [solver] table
+        solver_options = resolve_solver_options(
+            self.config.solver,
+            self.stoch_config.solver_options.get(self.config.solver_name, {}),
+            include_defaults=False,
+        )
 
         options = {
             'solver': self.config.solver_name,
diff --git a/temoa/model_checking/unit_checking/__init__.py b/temoa/model_checking/unit_checking/__init__.py
index 0db3c443f..4cfcd2c1c 100644
--- a/temoa/model_checking/unit_checking/__init__.py
+++ b/temoa/model_checking/unit_checking/__init__.py
@@ -3,8 +3,7 @@
 from pint import UnitRegistry
 from pint.errors import DefinitionSyntaxError
 
-# UnitRegistry is generic but doesn't require type args at instantiation
-ureg: UnitRegistry = UnitRegistry()  # type: ignore[type-arg]
+ureg: UnitRegistry = UnitRegistry()
 
 # Load custom unit definitions from the package resources
 _resource_path = 'temoa.model_checking.unit_checking/temoa_units.txt'
diff --git a/temoa/tutorial_assets/config_sample.toml b/temoa/tutorial_assets/config_sample.toml
index f903f330d..b262cf598 100644
--- a/temoa/tutorial_assets/config_sample.toml
+++ b/temoa/tutorial_assets/config_sample.toml
@@ -75,8 +75,15 @@ neos = false
 
 # solver (Mandatory)
 # Depending on what client machine has installed.
-#  [appsi_highs, cbc, gurobi, cplex, ...]
-solver_name = "appsi_highs"
+#  [appsi_highs, cbc, gurobi, cplex, ...]  (any solver available through pyomo's SolverFactory)
+# Either a solver name, which uses Temoa's default options for that solver:
+solver = "appsi_highs"
+# or a name plus options passed through to the solver, which are merged over Temoa's defaults
+# (use an inline table here, as a [solver] table header would capture the keys that follow it):
+# solver = { name = "gurobi", options = { Method = 2, Crossover = 0, BarConvTol = 1.0e-3, FeasibilityTol = 1.0e-4, BarOrder = -1 } }
+# Keep license credentials (e.g. gurobi WLS keys) in the solver's license file (gurobi.lic), not
+# in these options.
+# Note: 'solver_name' is deprecated but still accepted in place of 'solver'
 
 # ------------------------------------
 #             OUTPUTS
diff --git a/tests/conftest.py b/tests/conftest.py
index 444aebd50..7cb63eb9a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -185,8 +185,11 @@ def create_unit_test_dbs() -> None:
         logger.info('Created unit test DB: %s', db_name)
 
 
-def pytest_configure(config: Config) -> None:  # noqa: ARG001
+def pytest_configure(config: Config) -> None:
     """Setup test databases before test collection."""
+    # Skip for collect-only (e.g. IDE test discovery) so it can't race a real run for DB locks.
+    if config.getoption('collectonly'):
+        return
     refresh_databases()
     try:
         create_unit_test_dbs()
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 5ba1fa1ee..6e1551b9a 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -4,6 +4,7 @@
 from pathlib import Path
 
 import pytest
+import tomlkit
 from typer.testing import CliRunner
 
 from temoa.cli import _is_writable, app
@@ -127,7 +128,7 @@ def test_cli_validate_failure_on_invalid_db(tmp_path: Path) -> None:
     args = ['validate', str(test_config_path), '--output', str(tmp_path)]
     result = runner.invoke(app, args)
 
-    assert result.exit_code != 0, 'CLI should exit with a non-zero code on failure'
+    assert result.exit_code == 1, 'validate should exit 1 on a failed validation'
     assert 'Validation failed' in result.stdout
     # Check that the log was still created, containing the detailed error
     assert (tmp_path / 'temoa-run.log').exists()
@@ -138,7 +139,7 @@ def test_cli_run_missing_config() -> None:
     args = ['run', 'non_existent_file.toml']
     result = runner.invoke(app, args)
 
-    assert result.exit_code != 0
+    assert result.exit_code == 2, 'missing config file should be rejected as a bad argument'
     # Check that the error mentions the missing file (more robust than exact string match)
     assert 'non_existent_file.toml' in result.stderr
 
@@ -292,7 +293,7 @@ def mock_is_writable_always_false(_path: Path) -> bool:
     args = ['migrate', str(input_file)]
     result = runner.invoke(app, args, catch_exceptions=False)
 
-    assert result.exit_code != 0, 'Migration should fail with a non-zero exit code'
+    assert result.exit_code == 1, 'migrate should exit 1 when no writable output location exists'
     # Normalize whitespace to handle platform-specific line breaks from rich.print()
     normalized_output = ' '.join(result.stdout.split())
     assert 'Error: Neither input directory' in normalized_output
@@ -308,7 +309,7 @@ def test_cli_migrate_invalid_file() -> None:
     args = ['migrate', 'non_existent.sql']
     result = runner.invoke(app, args)
 
-    assert result.exit_code != 0
+    assert result.exit_code == 2, 'missing input file should be rejected as a bad argument'
     # Typer handles file existence check, so error is in stderr
     assert 'does not exist' in result.stderr or 'does not exist' in str(result.exception)
 
@@ -320,7 +321,7 @@ def test_cli_migrate_unknown_type(tmp_path: Path) -> None:
     args = ['migrate', str(unknown_file)]
     result = runner.invoke(app, args)
 
-    assert result.exit_code != 0
+    assert result.exit_code == 1, 'migrate should exit 1 for an undeterminable migration type'
     assert 'Cannot determine migration type' in result.stdout
 
 
@@ -433,7 +434,7 @@ def test_cli_validate_fails_if_solver_missing(
     args = ['validate', str(test_config_path), '--output', str(tmp_path)]
     result = runner.invoke(app, args, catch_exceptions=False)
 
-    assert result.exit_code != 0, (
+    assert result.exit_code == 1, (
         f'Validate should have failed: {result.exception}\n{result.stderr}\n{result.stdout}'
     )
     assert isinstance(result.exception, SystemExit)
@@ -459,7 +460,7 @@ def test_cli_run_fails_if_solver_missing(tmp_path: Path, monkeypatch: pytest.Mon
     args = ['run', str(test_config_path), '--output', str(tmp_path)]
     result = runner.invoke(app, args, catch_exceptions=False)
 
-    assert result.exit_code != 0, (
+    assert result.exit_code == 1, (
         f'Run should have failed: {result.exception}\n{result.stderr}\n{result.stdout}'
     )
     assert isinstance(result.exception, SystemExit)
@@ -469,3 +470,194 @@ def test_cli_run_fails_if_solver_missing(tmp_path: Path, monkeypatch: pytest.Mon
     # Use the more robust phrase for checking installation instructions
     assert 'Please ensure the solver is installed and accessible.' in result.stdout
     assert (tmp_path / 'temoa-run.log').exists()
+
+
+# =============================================================================
+# Tests for the `tutorial` command
+# =============================================================================
+
+
+def test_cli_tutorial_creates_files(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    """Test that `temoa tutorial` creates the config, database, and mc_settings files."""
+    monkeypatch.chdir(tmp_path)
+
+    args = ['tutorial', 'my_config', 'my_database']
+    result = runner.invoke(app, args, catch_exceptions=False)
+
+    assert result.exit_code == 0, f'CLI crashed with error: {result.exception}\n{result.stdout}'
+    assert (tmp_path / 'my_config.toml').exists()
+    assert (tmp_path / 'my_database.sqlite').exists()
+    assert (tmp_path / 'mc_settings.csv').exists()
+    assert 'Tutorial Setup Complete!' in result.stdout
+
+
+def test_cli_tutorial_default_names(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    """Test that `temoa tutorial` uses its default file names when none are given."""
+    monkeypatch.chdir(tmp_path)
+
+    result = runner.invoke(app, ['tutorial'], catch_exceptions=False)
+
+    assert result.exit_code == 0, f'CLI crashed with error: {result.exception}\n{result.stdout}'
+    assert (tmp_path / 'tutorial_config.toml').exists()
+    assert (tmp_path / 'tutorial_database.sqlite').exists()
+
+
+def test_cli_tutorial_updates_toml_database_paths(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Test that the generated config file points at the newly created database."""
+    monkeypatch.chdir(tmp_path)
+
+    result = runner.invoke(app, ['tutorial', 'cfg', 'db_name'], catch_exceptions=False)
+
+    assert result.exit_code == 0, f'CLI crashed with error: {result.exception}\n{result.stdout}'
+    doc = tomlkit.parse((tmp_path / 'cfg.toml').read_text())
+    assert doc['input_database'] == 'db_name.sqlite'
+    assert doc['output_database'] == 'db_name.sqlite'
+
+
+def test_cli_tutorial_verbose_output(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    """Test that `--verbose` prints the extra progress and guidance messages."""
+    monkeypatch.chdir(tmp_path)
+
+    result = runner.invoke(app, ['tutorial', 'cfg', 'db', '--verbose'], catch_exceptions=False)
+
+    assert result.exit_code == 0
+    assert 'Copying tutorial resources...' in result.stdout
+    assert 'Updating database paths in configuration...' in result.stdout
+    assert 'Tutorial files created successfully' in result.stdout
+
+
+def test_cli_tutorial_existing_files_aborts_without_force(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Test that existing tutorial files trigger a confirmation prompt that can be declined."""
+    monkeypatch.chdir(tmp_path)
+    (tmp_path / 'cfg.toml').write_text('placeholder')
+
+    result = runner.invoke(app, ['tutorial', 'cfg', 'db'], input='n\n')
+
+    # A declined confirmation is a graceful, non-error cancellation.
+    assert result.exit_code == 0
+    assert 'Tutorial files already exist' in result.stdout
+    assert 'Tutorial setup cancelled' in result.stdout
+    # The placeholder file should be untouched since the user declined.
+    assert (tmp_path / 'cfg.toml').read_text() == 'placeholder'
+
+
+def test_cli_tutorial_existing_files_force_overwrite(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Test that `--force` overwrites existing tutorial files without prompting."""
+    monkeypatch.chdir(tmp_path)
+    (tmp_path / 'cfg.toml').write_text('placeholder')
+
+    result = runner.invoke(app, ['tutorial', 'cfg', 'db', '--force'], catch_exceptions=False)
+
+    assert result.exit_code == 0, f'CLI crashed with error: {result.exception}\n{result.stdout}'
+    assert (tmp_path / 'db.sqlite').exists()
+    assert (tmp_path / 'cfg.toml').read_text() != 'placeholder'
+    assert 'Tutorial setup cancelled' not in result.stdout
+
+
+# =============================================================================
+# Tests for the `check-units` command
+# =============================================================================
+
+VALID_UNITS_DB = Path(__file__).parent / 'testing_outputs' / 'utopia_valid_units.sqlite'
+INVALID_CURRENCY_DB = Path(__file__).parent / 'testing_outputs' / 'utopia_invalid_currency.sqlite'
+
+requires_unit_dbs = pytest.mark.skipif(
+    not (VALID_UNITS_DB.exists() and INVALID_CURRENCY_DB.exists()),
+    reason='Test databases not created. Ensure conftest.py setup completed successfully.',
+)
+
+
+@requires_unit_dbs
+def test_cli_check_units_all_clear(tmp_path: Path) -> None:
+    """Test `temoa check-units` reports success on a valid database."""
+    args = ['check-units', str(VALID_UNITS_DB), '--output', str(tmp_path)]
+    result = runner.invoke(app, args, catch_exceptions=False)
+
+    assert result.exit_code == 0, f'CLI crashed with error: {result.exception}\n{result.stdout}'
+    assert 'All unit checks passed' in result.stdout
+
+
+@requires_unit_dbs
+def test_cli_check_units_all_clear_silent(tmp_path: Path) -> None:
+    """Test that `--silent` suppresses the success message."""
+    args = ['check-units', str(VALID_UNITS_DB), '--output', str(tmp_path), '--silent']
+    result = runner.invoke(app, args, catch_exceptions=False)
+
+    assert result.exit_code == 0
+    assert 'All unit checks passed' not in result.stdout
+
+
+@requires_unit_dbs
+def test_cli_check_units_detects_issues(tmp_path: Path) -> None:
+    """Test that `temoa check-units` fails and writes a report for a bad database."""
+    args = ['check-units', str(INVALID_CURRENCY_DB), '--output', str(tmp_path)]
+    result = runner.invoke(app, args, catch_exceptions=False)
+
+    assert result.exit_code == 1, 'check-units should exit 1 when issues are found'
+    assert 'Unit check found issues' in result.stdout
+    assert 'Detailed report saved to' in result.stdout
+    assert 'Report Summary:' in result.stdout
+    reports = list(tmp_path.glob('units_check_*.txt'))
+    assert len(reports) == 1
+
+
+@requires_unit_dbs
+def test_cli_check_units_detects_issues_silent(tmp_path: Path) -> None:
+    """Test that `--silent` suppresses the issue report summary but still fails and writes it."""
+    args = ['check-units', str(INVALID_CURRENCY_DB), '--output', str(tmp_path), '--silent']
+    result = runner.invoke(app, args, catch_exceptions=False)
+
+    assert result.exit_code == 1, 'check-units should exit 1 when issues are found'
+    assert 'Unit check found issues' not in result.stdout
+    reports = list(tmp_path.glob('units_check_*.txt'))
+    assert len(reports) == 1
+
+
+@requires_unit_dbs
+def test_cli_check_units_default_output_dir(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Test that omitting `--output` defaults the report to ./unit_check_reports."""
+    monkeypatch.chdir(tmp_path)
+
+    args = ['check-units', str(VALID_UNITS_DB)]
+    result = runner.invoke(app, args, catch_exceptions=False)
+
+    assert result.exit_code == 0
+    assert (tmp_path / 'unit_check_reports').is_dir()
+
+
+def test_cli_check_units_missing_database() -> None:
+    """Test graceful failure for a missing database file."""
+    args = ['check-units', 'non_existent_db.sqlite']
+    result = runner.invoke(app, args)
+
+    assert result.exit_code == 2, 'missing database file should be rejected as a bad argument'
+    assert 'non_existent_db.sqlite' in result.stderr
+
+
+# =============================================================================
+# Tests for `_is_writable`
+# =============================================================================
+
+
+def test_is_writable_true_for_writable_dir(tmp_path: Path) -> None:
+    """Test that a normal, writable directory is reported as writable."""
+    assert _is_writable(tmp_path) is True
+
+
+def test_is_writable_false_on_oserror(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    """Test that `_is_writable` returns False when touching the probe file raises OSError."""
+
+    def _raise_oserror(*_args: object, **_kwargs: object) -> None:
+        raise OSError('mocked failure')
+
+    monkeypatch.setattr(Path, 'touch', _raise_oserror)
+
+    assert _is_writable(tmp_path) is False
diff --git a/tests/test_evolution_updater.py b/tests/test_evolution_updater.py
new file mode 100644
index 000000000..6d3efbaa9
--- /dev/null
+++ b/tests/test_evolution_updater.py
@@ -0,0 +1,17 @@
+"""Tests for the myopic evolution_updater template module."""
+
+import logging
+
+import pytest
+
+from temoa.extensions.myopic.evolution_updater import iterate
+from temoa.extensions.myopic.myopic_index import MyopicIndex
+
+
+def test_iterate_logs_base_year(caplog: pytest.LogCaptureFixture) -> None:
+    idx = MyopicIndex(base_year=2020, step_year=2025, last_demand_year=2024, last_year=2030)
+
+    with caplog.at_level(logging.INFO):
+        iterate(idx=idx, prev_base_year=2015, last_instance_status='optimal', db_con=None)
+
+    assert 'base year 2020' in caplog.text
diff --git a/tests/test_framework_extension_helpers.py b/tests/test_framework_extension_helpers.py
new file mode 100644
index 000000000..4bc965322
--- /dev/null
+++ b/tests/test_framework_extension_helpers.py
@@ -0,0 +1,326 @@
+"""Tests for the extension-agnostic helper functions in temoa.extensions.framework.
+
+These cover the plumbing (id normalization, manifest/hook merging, and the
+enabled/disabled extension table checks) that isn't exercised by
+tests/test_extensions.py, which focuses on each concrete extension's model
+components.
+"""
+
+from __future__ import annotations
+
+import sqlite3
+from typing import TYPE_CHECKING, cast
+
+import pytest
+
+from temoa.extensions.framework import (
+    ExtensionSpec,
+    _append_extension_schema,
+    _table_exists,
+    _table_has_rows,
+    append_extension_manifest_items,
+    apply_model_extension_hooks,
+    assert_disabled_extension_tables_are_empty,
+    ensure_enabled_extension_tables_exist,
+    get_known_extension_specs,
+    merge_regional_group_tables,
+    normalize_extension_ids,
+)
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+    from temoa.data_io.loader_manifest import LoadItem
+
+
+# =============================================================================
+# normalize_extension_ids
+# =============================================================================
+
+
+def test_normalize_extension_ids_none_returns_empty() -> None:
+    assert normalize_extension_ids(None) == ()
+
+
+def test_normalize_extension_ids_empty_list_returns_empty() -> None:
+    assert normalize_extension_ids([]) == ()
+
+
+def test_normalize_extension_ids_dedupes_and_lowercases_preserving_order() -> None:
+    result = normalize_extension_ids(['Growth_Rates', ' growth_rates ', 'discrete_capacity'])
+    assert result == ('growth_rates', 'discrete_capacity')
+
+
+def test_normalize_extension_ids_skips_blank_entries() -> None:
+    assert normalize_extension_ids(['  ', 'growth_rates']) == ('growth_rates',)
+
+
+def test_normalize_extension_ids_rejects_non_string() -> None:
+    with pytest.raises(TypeError, match='Extension ids must be strings'):
+        normalize_extension_ids([123])
+
+
+# =============================================================================
+# merge_regional_group_tables
+# =============================================================================
+
+
+def test_merge_regional_group_tables_merges_specs_into_base() -> None:
+    spec = ExtensionSpec(extension_id='ext_a', regional_group_tables={'tbl_a': 'field_a'})
+    merged = merge_regional_group_tables({'tbl_base': 'field_base'}, [spec])
+    assert merged == {'tbl_base': 'field_base', 'tbl_a': 'field_a'}
+
+
+def test_merge_regional_group_tables_allows_identical_duplicate_mapping() -> None:
+    spec = ExtensionSpec(extension_id='ext_a', regional_group_tables={'tbl_base': 'field_base'})
+    merged = merge_regional_group_tables({'tbl_base': 'field_base'}, [spec])
+    assert merged == {'tbl_base': 'field_base'}
+
+
+def test_merge_regional_group_tables_conflict_raises() -> None:
+    spec = ExtensionSpec(extension_id='ext_a', regional_group_tables={'tbl_base': 'field_other'})
+    with pytest.raises(ValueError, match='conflicting field mappings'):
+        merge_regional_group_tables({'tbl_base': 'field_base'}, [spec])
+
+
+# =============================================================================
+# apply_model_extension_hooks / append_extension_manifest_items
+# =============================================================================
+
+
+def test_apply_model_extension_hooks_calls_each_registered_hook() -> None:
+    calls: list[object] = []
+    spec = ExtensionSpec(extension_id='ext_a', register_model_components=calls.append)
+    model = object()
+
+    apply_model_extension_hooks(model, [spec])  # type: ignore[arg-type]
+
+    assert calls == [model]
+
+
+def test_apply_model_extension_hooks_skips_specs_without_hook() -> None:
+    spec = ExtensionSpec(extension_id='ext_a')
+    # Should not raise even though register_model_components is None.
+    apply_model_extension_hooks(object(), [spec])  # type: ignore[arg-type]
+
+
+def test_append_extension_manifest_items_merges_in_order() -> None:
+    # Strings stand in for LoadItem; only list order matters here.
+    item_a = cast('LoadItem', 'item_a')
+    item_b = cast('LoadItem', 'item_b')
+    base_item = cast('LoadItem', 'base_item')
+    spec_a = ExtensionSpec(extension_id='ext_a', build_manifest_items=lambda _model: [item_a])
+    spec_b = ExtensionSpec(extension_id='ext_b', build_manifest_items=lambda _model: [item_b])
+
+    merged = append_extension_manifest_items(
+        object(),  # type: ignore[arg-type]
+        [base_item],
+        [spec_a, spec_b],
+    )
+
+    assert merged == [base_item, item_a, item_b]
+
+
+# =============================================================================
+# _table_exists / _table_has_rows
+# =============================================================================
+
+
+def test_table_exists_and_has_rows() -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        assert _table_exists(con, 'missing_table') is False
+        assert _table_has_rows(con, 'missing_table') is False
+
+        con.execute('CREATE TABLE populated (id INTEGER)')
+        con.execute('CREATE TABLE empty_table (id INTEGER)')
+        con.execute('INSERT INTO populated VALUES (1)')
+        con.commit()
+
+        assert _table_exists(con, 'populated') is True
+        assert _table_has_rows(con, 'populated') is True
+        assert _table_exists(con, 'empty_table') is True
+        assert _table_has_rows(con, 'empty_table') is False
+    finally:
+        con.close()
+
+
+# =============================================================================
+# assert_disabled_extension_tables_are_empty
+# =============================================================================
+
+
+def test_assert_disabled_extension_tables_are_empty_warns_when_populated(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        con.execute('CREATE TABLE limit_growth_capacity (region TEXT)')
+        con.execute("INSERT INTO limit_growth_capacity VALUES ('R1')")
+        con.commit()
+
+        with caplog.at_level('WARNING'):
+            assert_disabled_extension_tables_are_empty(con, enabled_specs=())
+
+        assert any('growth_rates' in record.message for record in caplog.records)
+    finally:
+        con.close()
+
+
+def test_assert_disabled_extension_tables_are_empty_silent_when_enabled(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        con.execute('CREATE TABLE limit_growth_capacity (region TEXT)')
+        con.execute("INSERT INTO limit_growth_capacity VALUES ('R1')")
+        con.commit()
+
+        growth_rates_spec = get_known_extension_specs()['growth_rates']
+        with caplog.at_level('WARNING'):
+            assert_disabled_extension_tables_are_empty(con, enabled_specs=(growth_rates_spec,))
+
+        assert not caplog.records
+    finally:
+        con.close()
+
+
+# =============================================================================
+# ensure_enabled_extension_tables_exist / _append_extension_schema
+# =============================================================================
+
+
+def test_ensure_enabled_extension_tables_exist_noop_when_tables_present() -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        con.execute('CREATE TABLE owned_table (id INTEGER)')
+        con.commit()
+        spec = ExtensionSpec(extension_id='ext_a', owned_tables=('owned_table',))
+
+        # Should not raise or prompt.
+        ensure_enabled_extension_tables_exist(con, [spec], input_database='db.sqlite', silent=True)
+    finally:
+        con.close()
+
+
+def test_ensure_enabled_extension_tables_exist_no_schema_path_raises() -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(extension_id='ext_a', owned_tables=('missing_table',))
+        with pytest.raises(RuntimeError, match='No schema SQL path is registered'):
+            ensure_enabled_extension_tables_exist(
+                con, [spec], input_database='db.sqlite', silent=True
+            )
+    finally:
+        con.close()
+
+
+def test_ensure_enabled_extension_tables_exist_silent_skips_prompt_and_raises() -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(
+            extension_id='ext_a', owned_tables=('missing_table',), schema_sql_path='unused.sql'
+        )
+        # silent=True means the prompt is never asked, so should_apply stays False.
+        with pytest.raises(RuntimeError, match='Re-run and accept the prompt'):
+            ensure_enabled_extension_tables_exist(
+                con, [spec], input_database='db.sqlite', silent=True
+            )
+    finally:
+        con.close()
+
+
+def test_ensure_enabled_extension_tables_exist_prompt_declined_raises(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(
+            extension_id='ext_a', owned_tables=('missing_table',), schema_sql_path='unused.sql'
+        )
+        monkeypatch.setattr('builtins.input', lambda _prompt: 'n')
+        with pytest.raises(RuntimeError, match='Re-run and accept the prompt'):
+            ensure_enabled_extension_tables_exist(
+                con, [spec], input_database='db.sqlite', silent=False
+            )
+    finally:
+        con.close()
+
+
+def test_ensure_enabled_extension_tables_exist_prompt_accepted_applies_schema(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    schema_file = tmp_path / 'extra_schema.sql'
+    schema_file.write_text('CREATE TABLE missing_table (id INTEGER);')
+
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(
+            extension_id='ext_a',
+            owned_tables=('missing_table',),
+            schema_sql_path=str(schema_file),
+        )
+        monkeypatch.setattr('builtins.input', lambda _prompt: 'y')
+
+        ensure_enabled_extension_tables_exist(con, [spec], input_database='db.sqlite', silent=False)
+
+        assert _table_exists(con, 'missing_table') is True
+    finally:
+        con.close()
+
+
+def test_ensure_enabled_extension_tables_exist_still_missing_after_apply_raises(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    # Schema file exists but doesn't actually create the owned table.
+    schema_file = tmp_path / 'noop_schema.sql'
+    schema_file.write_text('CREATE TABLE unrelated_table (id INTEGER);')
+
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(
+            extension_id='ext_a',
+            owned_tables=('missing_table',),
+            schema_sql_path=str(schema_file),
+        )
+        monkeypatch.setattr('builtins.input', lambda _prompt: 'y')
+
+        with pytest.raises(RuntimeError, match='still missing'):
+            ensure_enabled_extension_tables_exist(
+                con, [spec], input_database='db.sqlite', silent=False
+            )
+    finally:
+        con.close()
+
+
+def test_append_extension_schema_no_path_raises() -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(extension_id='ext_a')
+        with pytest.raises(RuntimeError, match='no schema SQL path configured'):
+            _append_extension_schema(con, spec)
+    finally:
+        con.close()
+
+
+def test_append_extension_schema_missing_file_raises() -> None:
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(extension_id='ext_a', schema_sql_path='/no/such/file.sql')
+        with pytest.raises(FileNotFoundError, match='not found'):
+            _append_extension_schema(con, spec)
+    finally:
+        con.close()
+
+
+def test_append_extension_schema_executes_and_commits(tmp_path: Path) -> None:
+    schema_file = tmp_path / 'schema.sql'
+    schema_file.write_text('CREATE TABLE new_table (id INTEGER);')
+
+    con = sqlite3.connect(':memory:')
+    try:
+        spec = ExtensionSpec(extension_id='ext_a', schema_sql_path=str(schema_file))
+        _append_extension_schema(con, spec)
+        assert _table_exists(con, 'new_table') is True
+    finally:
+        con.close()
diff --git a/tests/test_myopic_progress_mapper.py b/tests/test_myopic_progress_mapper.py
new file mode 100644
index 000000000..db024d520
--- /dev/null
+++ b/tests/test_myopic_progress_mapper.py
@@ -0,0 +1,87 @@
+"""Tests for MyopicProgressMapper, the console progress visualizer for myopic solves."""
+
+import re
+
+import pytest
+
+from temoa.extensions.myopic.myopic_index import MyopicIndex
+from temoa.extensions.myopic.myopic_progress_mapper import MyopicProgressMapper
+
+YEARS = [2020, 2025, 2030, 2035]
+
+
+def _index(base_year: int, step_year: int, last_demand_year: int) -> MyopicIndex:
+    return MyopicIndex(
+        base_year=base_year,
+        step_year=step_year,
+        last_demand_year=last_demand_year,
+        last_year=YEARS[-1] + 1,
+    )
+
+
+def test_init_computes_tag_width_and_positions() -> None:
+    mapper = MyopicProgressMapper(YEARS)
+
+    assert mapper.years == YEARS
+    assert mapper.tag_width == max(len(str(y)) for y in YEARS) + 2 * len(mapper.leader)
+    # Positions are in increasing order, one per year.
+    assert list(mapper.pos.keys()) == YEARS
+    assert all(mapper.pos[YEARS[i]] < mapper.pos[YEARS[i + 1]] for i in range(len(YEARS) - 1))
+
+
+def test_draw_header_prints_years_and_label(capsys: pytest.CaptureFixture[str]) -> None:
+    mapper = MyopicProgressMapper(YEARS)
+    mapper.draw_header()
+
+    out = capsys.readouterr().out
+    assert 'Myopic  Progress' in out
+    assert 'HH:MM:SS' in out
+    for year in YEARS:
+        assert str(year) in out
+
+
+def test_timestamp_format() -> None:
+    mapper = MyopicProgressMapper(YEARS)
+    assert re.match(r'^Elapsed: \d{2}:\d{2}:\d{2}\s+$', mapper.timestamp())
+
+
+@pytest.mark.parametrize(
+    'status,tag',
+    [
+        ('load', 'LOAD'),
+        ('solve', 'SOLV'),
+        ('check', 'CHEK'),
+        ('evolve', 'EVLV'),
+    ],
+)
+def test_report_prints_expected_tag_for_status(
+    capsys: pytest.CaptureFixture[str], status: str, tag: str
+) -> None:
+    mapper = MyopicProgressMapper(YEARS)
+    idx = _index(base_year=2020, step_year=2025, last_demand_year=2025)
+
+    mapper.report(idx, status)  # type: ignore[arg-type]
+
+    out = capsys.readouterr().out
+    # One tag per year from base_year through last_demand_year (2020, 2025).
+    assert out.count(tag) == 2
+    assert 'Elapsed:' in out
+
+
+def test_report_status_report_uses_step_year(capsys: pytest.CaptureFixture[str]) -> None:
+    mapper = MyopicProgressMapper(YEARS)
+    idx = _index(base_year=2020, step_year=2030, last_demand_year=2025)
+
+    mapper.report(idx, 'report')
+
+    out = capsys.readouterr().out
+    # One tag per year from base_year up to (not including) step_year: 2020, 2025.
+    assert out.count('RECD') == 2
+
+
+def test_report_rejects_invalid_status() -> None:
+    mapper = MyopicProgressMapper(YEARS)
+    idx = _index(base_year=2020, step_year=2025, last_demand_year=2025)
+
+    with pytest.raises(ValueError, match='bad status'):
+        mapper.report(idx, 'bogus')  # type: ignore[arg-type]
diff --git a/tests/test_stochastic_sequencer.py b/tests/test_stochastic_sequencer.py
new file mode 100644
index 000000000..84f506d2a
--- /dev/null
+++ b/tests/test_stochastic_sequencer.py
@@ -0,0 +1,53 @@
+"""Tests for StochasticSequencer's constructor validation of stochastic config files."""
+
+from pathlib import Path
+from types import SimpleNamespace
+
+import pytest
+
+from temoa.extensions.stochastics.stochastic_sequencer import StochasticSequencer
+
+
+def _config(stochastic_config: Path | None) -> SimpleNamespace:
+    """A minimal stand-in for TemoaConfig with just the attribute the sequencer reads."""
+    return SimpleNamespace(stochastic_config=stochastic_config)
+
+
+def test_missing_stochastic_config_raises() -> None:
+    with pytest.raises(ValueError, match="requires a 'stochastic_config'"):
+        StochasticSequencer(_config(None))  # type: ignore[arg-type]
+
+
+def test_nonexistent_stochastic_config_path_raises(tmp_path: Path) -> None:
+    missing = tmp_path / 'does_not_exist.toml'
+    with pytest.raises(ValueError, match='not found'):
+        StochasticSequencer(_config(missing))  # type: ignore[arg-type]
+
+
+def test_stochastic_config_path_is_directory_raises(tmp_path: Path) -> None:
+    with pytest.raises(ValueError, match='is not a file'):
+        StochasticSequencer(_config(tmp_path))  # type: ignore[arg-type]
+
+
+def test_invalid_toml_content_raises_wrapped_error(tmp_path: Path) -> None:
+    bad_toml = tmp_path / 'stoch.toml'
+    bad_toml.write_text('not valid = toml = content [[[')
+
+    with pytest.raises(ValueError, match='Error parsing stochastic config'):
+        StochasticSequencer(_config(bad_toml))  # type: ignore[arg-type]
+
+
+def test_valid_stochastic_config_loads_successfully(tmp_path: Path) -> None:
+    good_toml = tmp_path / 'stoch.toml'
+    good_toml.write_text(
+        """
+        [scenarios]
+        base = 0.5
+        high = 0.5
+        """
+    )
+
+    sequencer = StochasticSequencer(_config(good_toml))  # type: ignore[arg-type]
+
+    assert sequencer.stoch_config.scenarios == {'base': 0.5, 'high': 0.5}
+    assert sequencer.objective_value is None
diff --git a/uv.lock b/uv.lock
index f1913064d..dbf2fca40 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1474,7 +1474,7 @@ wheels = [
 
 [[package]]
 name = "pint"
-version = "0.25.3"
+version = "0.26.1"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "flexcache" },
@@ -1482,9 +1482,9 @@ dependencies = [
     { name = "platformdirs" },
     { name = "typing-extensions" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/52/9d/b1379cdbd33a49d17d627bc24e2b63cca06a1c5343b38072d2889499e82e/pint-0.25.3.tar.gz", hash = "sha256:f8f5df6cf65314d74da1ade1bf96f8e3e4d0c41b51577ac53c49e7d44ca5acee", size = 255106, upload-time = "2026-03-19T21:57:08.72Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/9f/bc/2c38c32e0fb1f966d3695f4493a3f3ce2cc0cca1bbe7c958b92261b31af9/pint-0.26.1.tar.gz", hash = "sha256:1bbde36eae57a5a289cd05081c6405618a5899814940752064ce351cd0204f71", size = 273631, upload-time = "2026-09-10T21:16:49.712Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/1b/dd/a9fe6a0a09512da23951c68bf36466aeecd89def3183dc095edbc807ddc5/pint-0.25.3-py3-none-any.whl", hash = "sha256:27eb25143bd5de9fcc4d5a4b484f16faf6b4615aa93ece6b3373a8c1a3c1b97d", size = 307488, upload-time = "2026-03-19T21:57:07.022Z" },
+    { url = "https://files.pythonhosted.org/packages/6d/5c/9507ea3c732f8a259f45ddf190a741e9bf7d3fe229b5d473917ee6efbf1e/pint-0.26.1-py3-none-any.whl", hash = "sha256:e982b129415c09c63308f314ae44697d83e5c96f253bcc0d5b833fc3329eb6d4", size = 326478, upload-time = "2026-09-10T21:16:48.316Z" },
 ]
 
 [[package]]