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.

Author

Jeremy Anderson — dcos.net

Related MCP server: reposynapse

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

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

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.

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/