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Taku Kudo

PROFILE

Taku Kudo

Over 21 months, this developer led core engineering efforts on google/mozc, delivering 143 features and 24 bug fixes focused on predictive text, input method architecture, and user history management. They modernized the prediction pipeline and dictionary subsystems, emphasizing modular C++ design, thread safety, and memory optimization. Their work unified desktop and mobile predictors, introduced LRU caching, and improved cross-platform reliability through API refactoring and asynchronous programming. By leveraging technologies such as Protocol Buffers and Bazel, they streamlined build systems and enabled safer, faster iteration. The resulting codebase is more maintainable, with enhanced input accuracy, lower latency, and robust personalization capabilities.

Overall Statistics

Feature vs Bugs

86%Features

Repository Contributions

349Total
Bugs
24
Commits
349
Features
143
Lines of code
96,302
Activity Months21

Work History

June 2026

6 Commits • 2 Features

Jun 1, 2026

June 2026: Delivered major API modernization and modularity improvements in the Mozc repository, coupled with user-facing prediction enhancements and a robust memory leak fix for model reloads. The work emphasized business value, reliability, and performance, enabling safer evolution of the conversion pipeline, faster iteration, and improved user experience in input predictions.

May 2026

7 Commits • 3 Features

May 1, 2026

May 2026 monthly work summary for google/mozc: This period focused on delivering user-history and predictor improvements, strengthening the integration between prediction and converter components, and enhancing performance and maintainability. Key outcomes include significant predictor enhancements, a unified flow for prediction and conversion, and memory/maintenance optimizations that reduce runtime footprint and prepare for ongoing personalization work.

April 2026

35 Commits • 14 Features

Apr 1, 2026

April 2026 monthly summary for google/mozc focused on delivering major feature work, performance improvements, and reliability enhancements across the dictionary and core data layers. Key outcomes include a per-pos cost model overhaul for user dictionary entries with a refactored UserPos, performance improvements in string-to-pos mapping via absl::flat_map, modularization of UserHistoryStorage for reuse, span-based iterator refactors and alignment improvements across rewriter/predictor, and targeted reliability fixes that improve cross-platform stability and maintainability.

March 2026

22 Commits • 12 Features

Mar 1, 2026

March 2026 monthly summary for google/mozc: Delivered core decoding enhancements with configurable BOS/context, refined suffix handling and penalty logic, and a unified, shared RealtimeDecoder across predictors. Implemented robust caching for suffix decoding and refreshed proper noun detection and user-history influence. Cleaned up legacy abstractions, introduced maintainable feature flags (Mendel), and completed several stability fixes. These changes collectively improve decoding accuracy, response latency, and user relevance while strengthening maintainability and testability.

February 2026

7 Commits • 3 Features

Feb 1, 2026

February 2026 monthly summary for google/mozc highlighting key product improvements, bug fixes, and technical achievements that drive business value and user experience. Overview: The team delivered a set of enhancements to improve personalization accuracy, dictionary-based POS tagging, and prediction quality, while preserving compatibility with legacy entries. A critical regression in ATOK POS handling was fixed, restoring accurate POS tagging. Refactors and API improvements set the stage for more robust personalization and rapid iteration.

January 2026

17 Commits • 6 Features

Jan 1, 2026

January 2026 (2026-01) deliverables focused on modernizing core user dictionary workflows, stabilizing input handling, and improving typing accuracy and user experience across Mozc. Architectural shifts include migrating from legacy UserDictionarySession to a thread-safe ImportUserDictionary API with a unified importer, simplifying storage access and improving error handling. In predictor and rewriting layers, the space_prefix toggle was removed post-launch to simplify logic. Substantial UX enhancements were implemented across typing and suggestions: IME_ACTION support and a new CommitContext API to synchronize edits with the converter, refined symbol rewriting and transliteration ranking (prioritizing Kana and half-width forms, demoting Hieroglyphs), and a rewriter strategy that prioritizes emoji over legacy emoticons. Candidate management gained a DELETABLE attribute with safeguards to keep top history aligned with top dictionary suggestions. Together, these changes improve reliability, performance, and user satisfaction while reducing maintenance complexity and technical debt.

December 2025

11 Commits • 6 Features

Dec 1, 2025

December 2025 for google/mozc focused on delivering UX improvements for English and Latin input, boosting decoder performance, and modernizing dictionary tooling. Major feature work spans an enhanced English input decoder, smarter Latin input history prediction, refined candidate scoring in the FST decoder, improved prediction annotation and literal formatting, and a modern, asynchronous, thread-safe dictionary import workflow. Overall, these changes improve input accuracy, responsiveness, and maintainability, enabling faster iterations and better user satisfaction across input modes.

November 2025

16 Commits • 6 Features

Nov 1, 2025

November 2025 highlights Mozc: focused on reliability, input quality, and developer productivity. Delivered a major architectural overhaul to user history management, improved language decoding for mixed Japanese-English input, and hardened data loading pipelines, while simplifying the codebase by removing a non-critical feature. Result: lower latency, higher reliability, and easier maintenance in production. Key outcomes include: a comprehensive User History storage and predictor overhaul with LRU caching and thread-safety enhancements; mode-aware Japanese-English input decoding improvements and English decoding support; decoder/prediction pipeline enhancements with config-gated suggestions, simplified flag usage, and a new mechanism to merge English decoder results while converting scores to Mozc costs; data loading thread-safety hardening via a TaskManager; richer UI rendering through a new RichText structure; stability work addressing flaky tests in the UserHistoryPredictorTest; and removal of the demote partial suggestion feature to simplify the codebase and reduce surface area. Impact: improved input quality and responsiveness for users, more robust multi-module data handling, and reduced maintenance burden for the Mozc codebase.

October 2025

19 Commits • 3 Features

Oct 1, 2025

October 2025: Consolidated performance in google/mozc with major User History Predictor improvements, data integrity hardening, and UX refinements. Delivered cross-device full-sentence caching, inner segment boundary handling, and standardized history data management; removed legacy cache sizing logic and flags to streamline maintenance. Strengthened robustness with UTF-8 validity checks and crash prevention for history processing. Enhanced mobile UX via display_value support and reduced confusing suggestions. Achieved extensive code cleanup and centralized demotion logic for easier future evolution, improving maintainability and predictability across components.

September 2025

24 Commits • 13 Features

Sep 1, 2025

2025-09 Monthly Summary for google/mozc: This period centered on fingerprint modernization, architecture decoupling, and data governance to boost search accuracy and system performance. Key features delivered include CityHash-based fingerprint modernization with CityFingerprint default usage in ExistenceFilter and 64-bit fingerprints; migration of legacy fingerprint references and deprecation of the slower 32-bit variant; and establishing independence of the existence-filter from specific fingerprint implementations. Additional enhancements include IsAvailalbe() support in the supplemental model; partial revert improvements with default enablement and updated bigram-chains; and broader improvements to mixed conversion, zero query suggestions, and candidate filtering. Data governance improvements removed the 62-day data-erasure window; ranking enhancements recently demoted short partial suggestions for result quality. API improvements include renaming GetResultType to IsValidResult, introducing a flag to control minimum value length for suppression, enabling post-corrections without inner segment boundary constraints, and simplifying Desktop candidate filtering. Major bugs fixed included removal of unused fingerprint functions to ensure CityHash compatibility and portability fixes such as switching hash results to size_t and addressing minor GetResultType semantics.

August 2025

27 Commits • 12 Features

Aug 1, 2025

August 2025 — Mozc: architecture modernization, safety, and performance improvements across core pipeline and APIs. Delivered InnerSegments-based history access and front/back segment operations; completed Converter Attribute refactor to converter::Attributes; simplified key/value generation and number/prefix decomposition. Achieved performance and memory gains by removing lattice cache in favor of thread_local allocation and adopting absl::string_view and absl::StrAppend. Strengthened reliability with AtomicSharedPtr usage, node allocator cleanup, and API migrations (dep. convertwithnodeinfo, bnext/enext), plus guardrails like unified cache size (1024) and a flag to disable joined (bigram) predictions. Also fixed critical bugs: InValid() semantics, mobile multi-segment exact-match suppression, and automated G4 rollback.

July 2025

17 Commits • 3 Features

Jul 1, 2025

July 2025 monthly work summary for google/mozc. Focused on delivering measurable business value through feature enhancements, data structure refactors, and architecture modernization; improved prediction accuracy, undo capabilities, and end-to-end maintainability.

June 2025

19 Commits • 5 Features

Jun 1, 2025

June 2025 Mozc (google/mozc) monthly summary focused on unifying and stabilizing the prediction engine across desktop and mobile, with a set of strategic refactors to reduce duplication, improve maintainability, and enable safer future iterations. The work delivered significant architectural and pipeline improvements, while also hardening the system with targeted bug fixes and parameter-driven configurability.

May 2025

21 Commits • 18 Features

May 1, 2025

May 2025 — google/mozc: Delivered API stability and modularity improvements, targeted bug fixes, and migration-ready refactors. Implemented immutable argument support for Predictor and Rewriter finish and revert, decoupled Segments from core Predictor surfaces, modernized API typing with absl::Span, and performed major DictionaryPredictor cleanup with Bigram storage improvements. Also introduced deprecations and API renames to simplify maintenance, aligning with long-term code health. Result: more reliable suggestions/history, easier future migrations, and reduced technical debt.

April 2025

20 Commits • 4 Features

Apr 1, 2025

April 2025 performance highlights for google/mozc focused on delivering business value through architectural decoupling, concurrency improvements, and maintenance hygiene. Key outcomes include enabling direct use of ConversionRequest in predictors through Segments decoupling, system-wide thread-safety and performance optimizations, and a leaner build/test footprint with deprecated legacy features retired. The work emphasizes reliability, scalability, and faster iteration in predictor workflows, while reducing maintenance costs.

March 2025

25 Commits • 8 Features

Mar 1, 2025

March 2025 (google/mozc) delivered a focused set of performance enhancements, stability improvements, and codebase simplifications to maximize end-user responsiveness and maintainability. The work emphasized near lock-free concurrency, safer APIs, and a smaller feature surface, enabling faster iteration and more predictable releases while reducing risk from deprecated components.

February 2025

30 Commits • 18 Features

Feb 1, 2025

February 2025 highlights across google/mozc focused on modernization, safety, and performance improvements. The team delivered a comprehensive architecture refactor and API cleanup that reduces maintenance burden while unlocking faster development cycles. Key features include a Session/Engine interface refactor with EngineConverter and reduced EngineOutput coupling, pointer/ownership modernization, and config handling via shared_ptr with a modernized ConfigHandler API. Additional work covers incognito mode support with lazy initialization, relocation of TransliteratorInterface to internal scope, and data handling refinements (HashOf for Table, ImeContext CopyableData) to improve correctness and performance. Cleanup efforts such as removal of usage_stats, tiny_storage/registry, and deprecated APIs further streamline the codebase and testing. Major impact areas include improved concurrency with std::atomic-based synchronization for the Connector cache, safer ownership models, reduced API surface, and clearer business value through more reliable input processing and faster iteration cycles.

January 2025

7 Commits • 1 Features

Jan 1, 2025

January 2025: Focused on engine and session architecture refactor and cleanup in google/mozc to enhance modularity, reliability, and long-term maintainability. Completed removal of deprecated interfaces and internal directories, reduced coupling by moving SessionConverter to the engine layer, and decoupling engine from converters and segments. Implemented robust initialization approach for UserDictionarySessionHandler to improve reliability without incurring unnecessary startup costs. These changes pave the way for faster feature delivery and easier future optimizations.

December 2024

15 Commits • 4 Features

Dec 1, 2024

December 2024, google/mozc: Key features delivered focused on architectural modernization, data-loading modernization, processing efficiency, and data-migration cleanup. Major bugs fixed by removing brittle dependencies, consolidating interfaces, and simplifying data paths. Overall impact: leaner, more modular engine with safer ownership, reduced maintenance burden, and improved startup and data-loading performance. Technologies demonstrated: modern C++ patterns, Abseil types, data-loader design, API surface reduction, and robust lifecycle management.

November 2024

3 Commits • 1 Features

Nov 1, 2024

November 2024 monthly summary for google/mozc: Delivered a feature to improve zero-query suggestion quality by reranking with a neutral classifier. This feature integrates into DictionaryPredictor and introduces a new virtual method in SupplementalModelInterface to support the classifier-based reranking, plus corresponding mock support. Interface refactors to enable more flexible candidate insertion: replaced pointer-based Result handling with absl::Span<Result>, and removed direct reliance on Result pointers to allow insertion of new candidates in the supplemental model.

October 2024

1 Commits • 1 Features

Oct 1, 2024

Concise monthly summary for 2024-10 for google/mozc focusing on key accomplishments, business value, and technical achievement. The main delivery this month was the Typing Correction System Overhaul in the typing pipeline, including API modernization and refactoring efforts. This work reduces technical debt and positions the project for easier future enhancements and improved user experience.

Activity

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Quality Metrics

Correctness93.0%
Maintainability90.2%
Architecture90.0%
Performance85.6%
AI Usage22.4%

Skills & Technologies

Programming Languages

BazelC++ProtoProtoBufProtocol BuffersPythonStarlarkgypprotoprotobuf

Technical Skills

API DesignAPI DevelopmentAPI IntegrationAPI MigrationAPI designAPI developmentAccess ControlAlgorithmAlgorithm DesignAlgorithm ImplementationAlgorithm OptimizationAlgorithm RefinementAlgorithm SelectionAlgorithmsAsynchronous Programming

Repositories Contributed To

1 repo

Overview of all repositories you've contributed to across your timeline

google/mozc

Oct 2024 Jun 2026
21 Months active

Languages Used

C++BazelProtocol BuffersPythonProtoStarlarkprotobufgyp

Technical Skills

Code MigrationRefactoringSoftware DesignAPI DesignAlgorithmsC++