March 2026 highlights for iiasa/message-ix-models focused on stabilizing the CI/testing workflow for ixmp/message-ix 3.11.0. The CI was updated to enforce pandas < 3 during pytest runs, preventing flaky results and ensuring reliable test outcomes across dependency updates. Key commit: 9c5cc249a127eeb68a403512d1d593899faab0cd; this work reduces CI churn and accelerates feedback for downstream analytics. Technologies exercised include Python, pytest, pandas version pinning, and GitHub Actions CI, demonstrating strong dependency management and test stabilization capabilities.

Month: 2026-02 This month focused on enhancing the documentation quality for the bilateralization tool in MESSAGEix within the iiasa/message-ix-models repository. The work improves clarity, structure, and maintainability, supporting faster onboarding and reducing potential user confusion. Deliverables emphasize documentation accuracy and alignment with established Sphinx/docs standards, paving the way for more reliable user guidance and lower support overhead.

January 2026 performance highlights: Achieved Pandas 3 readiness across core repositories, strengthened CI/test infrastructure, expanded data tooling, and enhanced documentation. Improvements reduce release risk, speed analytics workflows, and broaden data coverage for decision-support.

December 2025 monthly summary for the iiasa codebase focused on delivering business value through richer reporting, expanded transport modeling capabilities, and strengthened quality controls. Key outcomes include delivering Core Reporting and Scenario API enhancements, integrating exogenous pricing into transport workflows, expanding test coverage and documentation, and hardening data integrity and configurability across repos.

November 2025 delivered a targeted set of IAMC data tooling, data source integration, testing, and documentation improvements across iiasa/message-ix-models and iiasa/message_ix. The work enhances data validation, reporting reliability, and CI readiness, enabling faster validation and more robust releases. Key features delivered include: - Added util._message_ix.MESSAGE constant to standardize messaging and suppress warnings (commit fb8364be...). - Introduced IAMC data comparison tool (.tools.iamc.compare()) for fast IAMC data validation (commit d0e8dfcf...). - Added IAMC_NOT_IMPLEMENTED marker in reports to indicate non-implemented IAMC functionality (commit 95bb0e077...). - Integrated BACI data source with tests and ISO code mapping for CI-ready validation (commits 4c0f88a5..., 94d04070..., 1598303f..., fcfff6c4...). - Enhanced zipfile utilities with extract_if_newer() and usage refactor for reliability (commits a1d9a309..., d1ee7fba...). - Expanded testing & documentation: bilat historical_calibration and bilat.pull_gem tests, test_data_path fixture, and whatsnew/doc formatting updates (#178, #450, #451) (commits b96c03d2..., 34106577..., f943878d..., 24c466f2...). Major bugs fixed include: - Removed deprecated report.compat.assert_dims() and usages to reduce technical debt (commit 47e0fc50...). - Fixed f-strings in IAMC.compare for correctness and clarity (commit cc0cacb1...). - Improved import robustness for CLI and optional dependencies; deferred/guarded imports to allow CLI usage without full optional deps (commits 72350287..., a141a26d...). - Excluded report-only commodities from bare.get_spec to ensure correct reporting scope (commit 9f2dc897...). - Dropped the sha field from workflow message_data to fix dispatch payload (commit 504cd7ff...). - Silenced noisy logs for mix-models sbatch and ignored non-critical warnings (commits 4f253869..., 30e75770...). Overall impact and accomplishments: - Strengthened IAMC data handling and reporting, enabling faster validation and clearer non-implementation indicators, which reduces reviewer time and improves confidence in data integrity. - Enabled end-to-end data validation with BACI integration, improving realism of testing data and reducing regression risk. - Increased stability, test coverage, and documentation quality, supporting more reliable releases and onboarding of new contributors. - CI and platform resilience improvements (macOS runners, Python versions) reducing maintenance costs and build failures. Technologies/skills demonstrated: - Python modular refactoring, testing frameworks, and data tooling (IAMC, SDMX, BACI integration). - Data validation, extraction, and reporting pipelines with new utilities and operators. - CI/CD improvements, release automation, and documentation best practices. - Cross-repo collaboration, source control hygiene, and test-driven development.

October 2025: Stabilized currency unit configuration and parallel test reliability across two repositories. Delivered IAM units compatibility update and pytest-xdist cache isolation to reduce cross-worker interference, improving model deployment correctness and CI reliability.

September 2025 monthly summary for iiasa/message-ix-models focused on delivering essential data-model enhancements, stabilizing configuration, expanding DIGSY support, and strengthening documentation/testing. Key work spanned LDV load-factor handling, transport configuration, DIGSY scenarios, material reporting, and inter-package reliability improvements. The work emphasizes business value through improved data integrity, clearer data workflows, and more maintainable code paths.

August 2025 monthly summary for performance review: Delivered substantial enhancements across two repositories, focusing on data fidelity, scenario coverage, documentation, and code quality. The work improved business value by enabling richer transport modeling, robust reporting, and maintainable code foundations.

July 2025: Performance overview for iiasa/message-ix-models and iiasa/message_ix. Delivered documentation and release-readiness improvements, robust typing and CI quality work, and meaningful data/model enhancements that boost reliability, transparency, and business value. Key outcomes include standardized costs modeling, refactored material data cement, CI stability improvements, and data integration efforts supporting advanced emissions and technology coverage.

June 2025 monthly summary for iiasa/message_ix and iiasa/message-ix-models. Delivered significant business value through improved documentation, enhanced data modeling for emission pricing, robust transport data pipelines, URN/SSP integration, and strengthened CI/quality tooling across the two repositories. The work increases onboarding clarity for users, enables pricing-enabled analyses, and provides a more maintainable, testable data workflow for policy-relevant scenarios.

May 2025: Delivered targeted features and reliability improvements across two repositories, delivering business value through safer test data handling, dynamic transport data constraints, and richer API surfaces, while significantly stabilizing CI and documentation. Highlights span iiasa/message-ix-models (data controls, transport constraints, testing reliability, and API/data-structure enhancements) and iiasa/message_ix (CI/test hygiene, backend validation tooling, and expanded release/documentation practices).

April 2025 across iiasa/message-ix-models and iiasa/message_ix delivered a focused set of business-value features, reliability fixes, and infrastructure improvements. Highlights include: updated doc/whatsnew references to issues #312, #325, #326, #330, #333 and release notes entries #932–#936; configuration support for SSP data version 3.1; explicit Config(model=...) usage to improve clarity; simplified path handling in SSP Original/Update flows; and a fresh Context initialization in the CLI to prevent state leakage. In addition, testing and CI improvements were shipped: enhanced session_context fixture, transport test tooling, pytest workflow data caching, and v311 migration tooling. Major fixes include removing KeySeq in transport.base, creation of a fresh Context in CLI main, removal of Git LFS files for SSP 3.x, NaN handling in process_df, and updates to tests and translations (IEA EWEB transform, nodes_world_agg imports). Collectively these changes reduce risk, accelerate CI cycles, and improve data integrity and developer productivity. Technologies/skills demonstrated: Python, CI/CD optimization, pytest-based testing, typing and code quality improvements, GAMS-related adjustments, documentation tooling, and data/config management.

March 2025 performance highlights: A focused set of governance, tooling, and data-pipeline improvements across iiasa/message-ix-models, delivering clear business value and a stronger technical foundation for model runs and scenario analyses. Key features delivered include governance/update to code ownership for cost-tools (closes #301) and modular tooling changes (separate .tools.iamc.to_quantity()), enhancements to operator reporting API (typing improvements and new select_expand()), transport and dataflow improvements to consolidate data flows and add necessary dimensionality (including the y dimension), and notable performance gains in data processing (MappingAdapter.adapt()). In addition, structural refactors to move ExogenousDataFile into util.sdmx.Dataflow and to improve docstrings were completed to improve maintainability. These changes reduce maintenance overhead, accelerate development cycles, and improve reliability of outputs for policy-relevant scenario analysis.

February 2025 monthly work summary for iiasa repositories. Delivered impactful bug fixes, feature enhancements, and infrastructure improvements across iiasa/message_ix and iiasa/message-ix-models, focusing on business value, data interoperability, and developer productivity. Key outcomes include corrected PRICE_EMISSION pricing for mixed-duration periods, SDMX dataflow tooling, enhanced transport utilities, and substantial documentation/CI improvements that accelerate release readiness and cross-team collaboration.

January 2025 performance highlights across iiasa/message-ix-models and iiasa/message_ix focused on governance, data readiness, reliability, and performance to drive faster, safer, and clearer model workflows for stakeholders. The month delivered a robust concurrency capability for MACRO, data and typing enhancements for API stability, and significant improvements to documentation, CI/CD, and build times.

December 2024 monthly review for iiasa/message-ix-models: Delivered targeted data updates, transport workflow improvements, and testing/documentation enhancements. Maintained Python compatibility, expanded utilities, and cleaned up artifacts to improve model reliability, accuracy, and deployability. The work drives higher fidelity R12 scenario outputs, faster iteration cycles, and better collaboration across teams.

November 2024 (2024-11) delivered a set of targeted refactors, typing enhancements, and transport/data modernization across iiasa/message-ix-models and iiasa/message_ix. The work strengthened data integrity, improved type safety, and modernized CI tooling, enabling safer deployments and faster iteration in modeling pipelines.

October 2024 monthly summary for iiasa/message-ix-models: Delivered significant feature enhancements and groundwork that improve scenario composition, transport/operator utilities, freight handling, world aggregation, and IO/data handling. The month also included targeted bug fixes to improve error reporting and resilience. Key features delivered: - ScenarioInfo.__or__ operator added for fluent scenario composition (commit 0884a021d36cfb01554ffd21ae41db0712eb72c8). - Expanded transport and broadcasting capabilities: added expand_dims, improved broadcasting behavior with method=, and made broadcast_n dim kwarg optional (commits 824f9cd63ae97238131a3c1ad66a80622da97c06; e004c6c0b560ff7f0e49e49e88a6204e9db27c8f; 53d65f5c6b8770bebad2e5ecb12eacd8043b2199; 6debc3b42f62ade0f4ee8831802902b4cf643f29). - Freight handling and IDs standardization: freight_usage_output reporting; standardize tech/commodity IDs with F {RAIL, ROAD}; use transport F IDs in demand/tests; mark hybrid techs as electr and lightoil (commits a125653a03a0e42bc0d6ce96bc8dbbef6fad1ccc; 1190a7b8dae7664f38dc541ea4629bcc7245c8fc; d15f82cf6276eb8af82481b6c21b850202d02696; 820422382616d8cfc372007d6d4c5a816018f6f9; 0c69fbd28f367a535f4dce328a724c21ce341fe1). - World aggregation and testing infrastructure: use get_codelist() in nodes_world_agg(); adapt dummy_supply() for multi-input techs; introduce typing markers for transport tests (commits 8dac693f8bc37a66d149d7a8b86eb6b4123417ef; 7b4283d43dfd64f3ae7b9f1ce082e2c85edf5bb0; 9ed16f3ea6758f4b878d4bb7d87d674ac02ac168; d32d76304b4870059f9cb5739a3835da789ec6cf). - IO/data handling and typing enhancements: convert_units() accepts DataFrame and dict; improve build.add_structure(); support dict and DataFrame in util.same_{node,time}; type .util.make_io(); extend make_matched_dfs() to support replacement (commits 2e20fef8f024c1ea2dfae7f5232b472cad8d1718; dfbfd6ff6d71b211781b31204731ca3de17ac276; cdd84f6160c1e08bb06146e50a3817ee2c2a2a2d; 208411e97abd4241508bc510c2b154cf7e0be9c0; d0a6ff9e847b124b909c6c27c4c535f8f96b31b0). - ScenarioInfo.update(): warn instead of raising (bug fix) – contributes to resilience during iterative model runs (commit 3c609caf3dcad1dd82a5b3c56d29dddc874b93d9). Major bugs fixed: - ScenarioInfo.units_for() now raises an informative exception to aid diagnosis of misuse. - ScenarioInfo.update() now issues a warning rather than raising, improving robustness during batch updates. Overall impact and accomplishments: - Enabled more expressive and safer scenario composition, leading to faster modeling cycles and reduced debugging time. - Strengthened data handling and IO pathways, improving interoperability with DataFrame inputs and static typing for testing, resulting in more reliable pipelines. - Standardized IDs and improved freight reporting, supporting clearer data lineage and easier integration with downstream systems and tests. - Enhanced testing infrastructure and world aggregation workflows, enabling more scalable scenario runs and easier maintenance. Technologies/skills demonstrated: - Python, advanced typing, and static analysis practices. - Data handling with pandas (DataFrame support in utilities). - Modular design, API ergonomics for scenario composition, and robust error handling. - Testing infrastructure improvements and maintainable code hygiene.

September 2024 monthly summary for iiasa/message-ix-models: Delivered key enhancements to expand modeling capabilities and improve maintainability. Key features and milestones include: 1) New freight transport modes for rail and road (electric and light oil powered technologies) enabling more diverse scenario analyses via F RAIL mode and technologies. 2) Aviation emissions postprocessing scaffold establishing a CLI entry and stub processor to lay groundwork for future emissions calculations. 3) Internal code refactor to improve modularity: relocated iamc_like_data_for_query to .tools.iamc and quantity_from_iamc to .report.operator for clearer responsibilities and easier maintenance. 4) Documentation stub for ScenarioMIP project linking to SSP docs, signaling future alignment and governance. These changes deliver earlier business value by expanding modeling capabilities, reducing future maintenance costs, and setting foundation for robust emissions analysis and ScenarioMIP integration.

August 2024 monthly summary for iiasa/message-ix-models: Delivered a Navigate module refactor and dependency cleanup, eliminating deprecated components and consolidating imports to improve maintainability and reduce runtime risk. The changes streamline the codebase, support faster future iterations, and lower maintenance costs by removing legacy code paths.

April 2024: Key delivery across legacy reporting, IAMC reporting configurability, and accuracy fixes for energy modeling, complemented by testing framework improvements and CLI UX refinements. This period delivered tangible business value: improved data fidelity for legacy outputs, flexible and testable reporting configurations, and quieter, more usable CLI workflows.

March 2024 monthly summary for iiasa/message-ix-models focused on code quality, dependency compatibility, and maintainability enhancements. Highlights include formatting standardization, configuration restructuring, and type updates to align with newer dependencies, setting a stronger foundation for future feature work and reliability.

December 2023 monthly summary for iiasa/message-ix-models: Delivered a config-driven Legacy Reporting System enabling toggling legacy reporting via configuration and report function parameters, plus targeted adjustments to the legacy path to ensure safe migration. Implemented selective use of legacy reporting for materials only when configured and excluded legacy reporting from the transport workflow to reduce pipeline complexity. Addressed CI instability by temporarily skipping flaky test_add_macro on GitHub Actions, preventing CI crashes and enabling focused investigation. This work improves configurability, reduces risk during migration, and enhances CI reliability.

November 2023 performance summary for iiasa/message-ix-models: Delivered key features and stability improvements, focusing on a more usable CLI, API modernization, and enhanced reporting capabilities. Implemented name-based workflow callbacks, modernized API usage (replacing deprecated imports and eval_annotation usage), and enhanced the reporting module with flexible outputs, configuration hooks, and legacy compatibility. These changes reduce future breakages and improve business value for users relying on automated workflows and reporting.

October 2023: Completed a major NAVIGATE CLI overhaul for iiasa/message-ix-models, delivering a streamlined workflow and semantic alignment with genno. Core changes include renaming the transport computations module to operator, replacing the run command with a modular workflow command, and consolidating to a single navigate run entry point while removing obsolete prep_submission and gen_workflow commands. Tests updated to reflect the changes and ensure safety of the workflow. Key commits illustrate the refactor: 7857e541b5f8d0547bff040140a0b7219149dee4 (Rename .transport.computations to .operator), 37dfc354a7d2103e457cdac6a6e2f22c2bee1020 (Replace .navigate.cli.run with make_workflow_command()), 7f1da5f0cb88b3b960d2b0fa7cda353860aad407 (Remove "navigate {gen_workflow,prep_submission}" cli).

2023-09 monthly summary for iiasa/message-ix-models focusing on key accomplishments, major bugs fixed, impact, and skills demonstrated. The month delivered targeted enhancements to improve model accuracy, reporting reliability, and developer productivity, while stabilizing core workflows used for energy-system analysis and IAMC-aligned outputs.

August 2023 monthly summary for iiasa/message-ix-models focusing on delivering robust navigation workflow enhancements, policy/config updates, CTAX emissions improvements, and code quality and observability enhancements. The work improved forecast accuracy, policy compliance, and operational performance across the model workflow, with explicit attention to business value and maintainability.

July 2023 performance summary for iiasa/message-ix-models: Delivered foundational workflow enhancements and data integration work that improve flexibility, regional representation, and performance, while fixing calibrations and raising code quality. The month focused on enabling safe experimentation, richer sector representation, and more maintainable codebase to support faster iteration and business value realization.

June 2023 monthly summary for iiasa/message-ix-models: Automated and stabilized the navigate workflow macro lifecycle, expanded upstream integration, and added graph visualization. Implemented robust macro orchestration, expanded data preparation and parameter coverage, and hardened solving logic. Delivered targeted bug fixes and quality improvements that reduce manual steps, improve data quality, and accelerate feature delivery across the workflow.

May 2023 (iiasa/message-ix-models) focused on delivering core navigation and data-management capabilities, strengthening code quality, and expanding robust workflow support for WP2/WP6. The work improved reliability, reproducibility, and scalability of model navigation and limit calculations while reducing technical debt and setting the groundwork for future enhancements.

April 2023 monthly summary for iiasa/message-ix-models focusing on delivering a transport-optional, WP6-aligned climate policy workflow and improving data quality. Implemented end-to-end support for 20C and T6.2 scenarios with enhanced navigation/configuration, streamlined scenario labeling, and materials processing refinements to support policy analyses. Key changes include a CLI option and handling when transport is disabled, refined materials base and step naming for WP6, and extended scenario naming to distinguish WP6 variants. In addition, introduced data hygiene improvements by adding policy data removal (strip_policy_data) and cleaning emission-related data in navigate m scenarios to improve reproducibility. Impact: Faster, more reliable climate policy simulations with reduced manual data wrangling, enabling consistent comparisons across WP6 scenarios and better decision support for policy teams. Technologies/skills demonstrated: Python workflow enhancements, CLI integration, configuration-driven workflow, data cleaning and reproducibility practices, scenario labeling conventions, and robust handling of optional transport modes.

Concise monthly summary for 2023-03 focusing on key features delivered, major bugs fixed, impact, and skills demonstrated for iiasa/message-ix-models. Highlights across three changes: bug fix for emissions data integrity and tax emission calculation; CLI Target Selection Enhancement with regex-based matching; testing framework improvement using test_context fixture. Business value: ensured accurate emissions calculations, improved CLI usability and error handling, and strengthened test coverage and CI reliability.

February 2023 — iiasa/message-ix-models: Implemented navigation and reporting mapping enhancements to improve report accuracy and navigation UX; strengthened code quality with type-safety fixes and updated tests; expanded test coverage to reflect workflow changes, improving maintainability and reducing regression risk. This work directly supports more reliable scenario reporting and smoother onboarding for changes.

January 2023 monthly summary for iiasa/message-ix-models focused on delivering robust data handling, accurate reporting, and scalable workflow improvements that directly enhance business value and decision support. The team completed a broad set of features and bug fixes across buildings integration, reporting, and navigate workflows, with strong emphasis on data integrity, maintainability, and developer productivity.

December 2022 monthly summary for iiasa/message-ix-models focused on delivering a more robust data pipeline, expanded scenario capabilities, and improved code quality. Key features delivered include updates to buildings/set.yaml with structure information and end-use naming, a refactored buildings build pipeline with separated structure/data prep, and enhanced navigate workflow with a new nav_dem-ctax-ref scenario, updated model horizon, and associated workflow/config. Additional improvements include adding tests for navigate and applying Black formatting to navigate code, and computing residential/commercial/combined final energy using genno.

November 2022 (2022-11) monthly summary for iiasa/message-ix-models: Delivered end-to-end workflow enhancements and reliability improvements across the navigate workflow, Sturm integration, and building system. Strengthened testing infrastructure and configuration management to accelerate releases and reduce regression risk. Business value focused on accurate scenario visualization, up-to-date policy impact analysis, and stable model runs for stakeholder reporting.

October 2022 — iiasa/message-ix-models: Delivered end-to-end Navigate workflow integration with CLI, reporting, and formatting utilities; Sturm enhancements with tests; and a substantial build-system refactor with upstream integration and stronger typing. Focused on business value: repeatable workflows, robust data processing, and scalable configuration to accelerate reliable model outputs. Improved error visibility and documentation hygiene.

September 2022 (2022-09) focused on delivering end-to-end modeling improvements in iiasa/message-ix-models, with a strong emphasis on expanding the navigation/buildings/demands workflow, hardening Sturm integration, and enhancing reporting, data definitions, and maintainability. The month combined feature enrichments, data/config improvements, and systematic refactoring with targeted bug fixes to improve reliability, traceability, and business value.

August 2022 monthly summary for iiasa/message-ix-models focusing on delivering key features, stabilizing reliability, and enabling faster experimentation. Major items include Buildings CLI enhancements, Sturm integration and caching, model.buildings code organization, building reporting improvements and integration, and documentation/navigation updates. These changes deliver measurable business value through faster iteration, improved reporting accuracy, and a more maintainable codebase.

July 2022: Delivered consolidated Scenario Execution and Reporting enhancements for iiasa/message-ix-models, enabling faster scenario builds, richer reporting outputs, and clearer CLI usability for climate scenarios. Documentation updates improved discoverability and usage.

In June 2022, delivered a new NAVIGATE CLI in iiasa/message-ix-models and strengthened accompanying documentation. No major bugs fixed this month. This work improves user interaction, onboarding, and sets the groundwork for future CLI enhancements, delivering clear business value and showcasing solid CLI development and documentation skills.

For 2022-04, delivered a robust set of enhancements to iiasa/message-ix-models focused on CLI scaffolding, platform integration, data processing performance, architectural clarity, and code quality/documentation. The work emphasizes business value through improved usability, faster model runs, easier maintenance, and clearer platform integration, enabling faster iteration and more reliable results for building-focused scenarios.

2021-08 Monthly Summary: Focused on improving developer onboarding and maintainability through documentation for MESSAGEix-Buildings within the iiasa/message-ix-models repository. Delivered a new documentation page outlining MESSAGEix-Buildings purposes and linking to the related repository; prepared the groundwork for future content with a stub page. No major bugs fixed this month as the priority was clarity and documentation quality.

April 2021 monthly summary for iiasa/message-ix-models: Focused on maintaining test suite compatibility with upstream changes, with no new feature deliveries this month. Key bug fixed: Test Tools Import Compatibility with Upstream Changes, ensuring test_tools.py imports align with upstream repository structure and dependencies. This change preserves CI stability as upstream evolves.

Monthly summary for 2019-10 (iiasa/message-ix-models): Implemented CO2 accounting modules for AFOLU/FFI and Emission Budget Framework in message_ix, enabling emission constraints and budget management in scenarios. Completed repository refactor moving files into message_data and adding an __init__.py to improve packaging. No major bugs reported this month. This work strengthens business value by enabling more accurate emissions accounting and scalable project structure.