MCP Drift State Tracker

MCP server that enforces code completeness, intercepts context erosion, and neutralizes LLM output degradation across multi-language repository workspaces.

Pure TypeScript. JSON-driven language profiles. Zero Python. Zero runtime bloat.

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Author

Jeremy Anderson — dcos.net

What It Does

LLMs degrade output quality as context windows fill: they drop imports, leave stub bodies, omit function implementations, and produce structurally incomplete code. This server provides a real-time audit layer over any MCP-compatible coding client, flagging those patterns before they persist in the codebase.

Core Capabilities

• Multi-language parsing — 20+ languages supported via data-driven JSON profiles. No per-language parser classes.
• Stub and placeholder detection — flags pass, TODO, FIXME, raise NotImplementedError, undefined, return null, and language-specific stub patterns.
• Import and dependency tracking — verifies that declared imports correspond to symbols used in the file.
• Structural completeness verification — confirms that declared classes, functions, and interfaces have non-empty bodies.
• Drift scoring — assigns a numeric drift score to files and sessions to quantify context erosion.
• State persistence — writes audit state to .mcp_drift_state.json at the repository root for cross-session continuity.

Architecture

The parsing engine is entirely data-driven. A single index.ts runtime loads language_profiles.json at startup, compiles all regex patterns once, and dispatches files to the correct parsing strategy via a flat extension-to-profile dispatch table. No cascading conditionals. No nested control flow.

index.ts                          MCP server runtime
├── language_profiles.json        language definitions, dispatch table, aliases
├── controller_config.json        downstream AI service endpoints
├── mcp_config.json               client integration reference config
└── Makefile                      standardized build and deploy targets

Language Support

Category	Extensions	Strategy
C-style / Brace	.js .jsx .ts .tsx .c .cpp .h .hpp .java .cs .kt .kts .swift .dart .pike .pmod .r	Brace-depth counting via cStyleDefault
Brace (custom)	.rs .go .php .hack .sh .zsh .ps1	Per-language regex overrides in braceProfiles
Block-end keywords	.jl .lua .ex .exs .adb .ads .au3 .vbs	Start/end keyword pairing with nest-depth increment rules
Sequential labels	.bat .cmd .sql	Label-based or statement-delimited flow
Indentation-sensitive	.mojo .hs .elm	Signature detection with indent-level body verification

Duplicate profiles (.sh/.zsh/.ps1, .ex/.exs, .adb/.ads, .bat/.cmd, .php/.hack) resolve through the _aliases map in language_profiles.json. Adding a new language requires appending one entry to the dispatch table and restarting the server.

MCP Tools

Tool	Purpose
scan_file	Scan a single source file for drift indicators
scan_workspace	Recursively scan a workspace directory, respecting globalIgnoreDirs
get_drift_report	Retrieve accumulated drift state and scores
reset_drift_state	Clear drift state to begin a fresh audit session

Requirements

• Node.js >= 20.0.0
• npm (bundled with Node.js)

Installation

git clone https://git.dcos.net/dcosnet/mcp-drift-state-tracker.git
cd mcp-drift-state-tracker
make

Running

make dev       # development, no compile step
make prod      # compile and run
make inspect   # interactive MCP tool testing via Inspector

Configuration

language_profiles.json

All language-specific regex patterns, stub detectors, file extension routing, and ignore rules. Validated against the inline $schema. Key structure:

• _dispatch — flat lookup table mapping every supported extension to its profile category and profile key. The runtime resolves extensions in O(1) without cascading conditionals.
• _aliases — maps duplicate extensions to their canonical profile key.
• _stubDefaults — common stub patterns applied to profiles that omit an explicit stubs array.
• globalIgnoreDirs — directories skipped during workspace scans.
• stateFileName — per-repo state file name.
• cStyleDefault — fallback regex set for brace-matching languages.
• braceProfiles / braceExtensions — custom overrides and extension lists.
• blockEndProfiles — start/end keyword patterns.
• sequentialProfiles — label-based flow definitions.
• indentationProfiles — indent-sensitive language definitions.

controller_config.json

Downstream AI service endpoints. All ports are integers. All service keys are lowercase slugs. The base_dir follows FHS conventions.

Service	Port	Purpose
ollama	11434	Local inference engine
open-webui	8080	Browser-based LLM chat interface
aider-web	8501	Web frontend for Aider
hermes	8000	Orchestration proxy
odysseus	7000	Orchestration proxy
dify-engine	5001	Workflow automation platform

mcp_config.json

Client integration reference. Uses ${MCP_TRACKER_PATH} environment variable for path resolution — set once, referenced everywhere.

License

AGPL-3.0 — Copyright (c) 2026 Jeremy Anderson. dcos.net

Repository

https://git.dcos.net/dcosnet/mcp-drift-state-tracker/