AssistAI - Eclipse IDE as an MCP Server for AI Agents
AssistAI is an Eclipse IDE plugin that exposes your entire development environment as an MCP (Model Context Protocol) server. External AI agents -- Claude Code, OpenAI Codex, Claude Desktop, or any MCP-compatible client -- can read, navigate, edit, build, test, run, and debug your Java projects directly through Eclipse, preserving workspace sync, local history, and incremental compilation.
AssistAI also includes a built-in LLM chat view for quick inline interactions with any supported model.
Eclipse IDE as an MCP Server for AI Agents
2026-10-26
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Why MCP through Eclipse?
When AI agents edit files through the filesystem directly, Eclipse doesn't know anything changed. Editors show stale content, incremental compilation misses updates, and local history gaps appear.
AssistAI solves this by routing all operations through Eclipse APIs:
Edits go through JDT -- incremental compilation fires immediately, errors update in real time
Refactorings use Eclipse's refactoring engine -- renames, moves, and package restructures update all references across the workspace
File reads reflect the editor buffer -- agents always see the latest unsaved content, not the on-disk version
Local history is preserved -- every change is tracked, undoable through Eclipse's local history
Tests run inside Eclipse -- JUnit results, console output, and compilation errors are accessible as tool responses
Getting Started with External Agents
1. Enable the HTTP MCP Server
Open Window > Preferences > Assist AI > HTTP MCP Server
Any client that supports MCP over Streamable HTTP can connect directly to the endpoint URLs. Use the Authorization: Bearer <token> header for authentication.
3. What Agents Can Do
With the MCP tools, an external agent can:
Read and navigate code -- project layout, class outlines, method source, type hierarchies, call hierarchies, find references
Inspect workspace images -- return raster resources as native MCP image content for vision-capable agents
Browse and restore file history -- list Local History versions, view old content, restore to any previous version, diff current vs. historical
Inspect the resource cache -- see what files/classes are loaded in the conversation context, read cached content without I/O
Manage Git repositories -- status, log, diff, stage, commit, branch, checkout, stash -- all through EGit, keeping Eclipse workspace in sync
Navigate large documents -- get the heading outline of a Markdown file, then fetch specific sections without loading the entire content
4. Guiding Agents with Eclipse Context
External agents don't know what you're looking at in Eclipse -- unless they ask. AssistAI provides MCP tools that let agents pick up context from your IDE session, so you can guide their work by simply opening files, selecting code, or running programs:
What you do in Eclipse
Tool the agent calls
What the agent sees
Open a file in the editor
getCurrentlyOpenedFile
Full file content with path, project name, and line numbers
Select a code region
getEditorSelection
Selected text with start/end line numbers and surrounding file context
Run or debug a program
getConsoleOutput
Recent stdout/stderr from Eclipse console(s)
Have compilation errors
getCompilationErrors
All errors/warnings with file, line, and message
Open a specific class
getClassOutline
Compact structure -- fields, method signatures, line numbers
Workflow tip: When asking an agent to fix something, open the relevant file in Eclipse first, select the problem area, and tell the agent to check your selection. This gives the agent precise context without you having to describe file paths or paste code.
Token-efficient navigation: Instead of reading entire files, agents can use getClassOutline to see the structure (~30 lines for a 500-line class), then getMethodSource to read only the methods they need, or getFilteredSource to see the full file with irrelevant methods collapsed to one-line signatures. The readProjectResource tool supports excludeImports to further reduce token usage.
Workspace images: Vision-capable agents can call readImageResource(projectName, resourcePath) to receive an image as native MCP ImageContent instead of base64 text. The tool supports PNG, JPEG, GIF, BMP, TIFF, and ICO resources up to 20 MiB, and enforces the same .aiignore/.noai access rules as text reads. For example: readImageResource(projectName="my-project", resourcePath="docs/architecture.png").
Resource cache: Files and classes read through Eclipse MCP tools are automatically cached with version tracking and file modification timestamps (tied to Eclipse's Local History). Agents can call listCachedResources to see what's already loaded, or getCachedResource to re-read cached content instantly -- no disk I/O, no re-parsing.
Local History: Eclipse automatically maintains a Local History for every file modified through the IDE. Agents can browse past versions (getFileHistory), read historical content (getFileHistoryContent), compare with the current version (compareWithHistory), or restore to any previous state (restoreFileVersion). This is more powerful than a simple undo -- it preserves every edit across the entire session, including changes made by the agent itself.
MCP Tool Reference
eclipse-coder -- Code Editing
Tool
Description
createFile
Creates a new file, adds it to the project, and opens it in the editor
insertIntoFile
Inserts content at a specific position in an existing file
replaceString
Replaces a specific string in a file, optionally within a line range
applyPatch
Atomically applies a validated unified diff, preserves line endings, supports multi-hunk edits, creates an undo backup, and reveals the first changed line
formatFile
Formats a file using its registered Eclipse editor formatter (Java, XML, JSON, HTML, SQL, and other supported editors)
undoEdit
Restores a file from its backup (undo last edit)
createDirectories
Creates a directory structure recursively
renameFile
Renames a file in a project
deleteFile
Deletes a file from a project
replaceFileContent
Replaces the entire content of a file
deleteLinesInFile
Deletes a range of lines (1-based indexing)
refactorRenameJavaType
Renames a Java type using Eclipse's refactoring, updating all references
refactorRenameJavaElement
Renames the method, field, local, parameter, type parameter or type at a line and column, updating all references
refactorExtractTypeToNewFile
Extracts a nested Java type to a new top-level Java file using Eclipse's refactoring
refactorMoveJavaType
Moves a Java type to a different package, updating all references
refactorRenamePackage
Renames a package, updating all declarations and references
moveResource
Moves a file or folder to a different location
organizeImports
Removes unused imports and sorts existing imports; does not add missing imports
organizeImportsInPackage
Removes unused imports and sorts existing imports across a package
Direct file-editing tools complete a workspace synchronization barrier before returning: the content is saved, the resource is refreshed, pending workspace notifications are checkpointed, cached content is updated, Java compilation units are made consistent, and the editor reveals the changed line. Their response includes the synchronization state and resulting modification stamp. Multi-file operations reveal the primary or first changed file.
eclipse-ide -- Code Analysis, Navigation & Build
Tool
Description
getSource
Source of a workspace or referenced-library class; prefers attached source JARs and decompiles binaries when source is unavailable
explainTypeResolution
Explain how a type resolves in a specific project's JDT classpath: source/binary origin, root, entry, attachment, class file, and source/decompilation strategy
getClassOutline
Compact class outline -- declarations and method signatures (no bodies) with line numbers and each member's Javadoc summary
getMethodSource
Source of specific methods by name, with overload disambiguation
getFilteredSource
Full source with non-selected methods collapsed to signatures
readProjectResource
Read a text resource, with optional import block collapsing
readImageResource
Return a workspace image as native MCP ImageContent (PNG, JPEG, GIF, BMP, TIFF, or ICO; maximum 20 MiB)
getJavaDoc
Rendered JavaDoc of a type and its members, inherited text included
formatCode
Format code using Eclipse formatter settings
getProjectProperties
Project properties and configuration
getProjectLayout
File/folder structure with scopePath and maxDepth support
listProjects
All workspace projects with detected natures
listMavenProjects
All Maven projects in the workspace
getCurrentlyOpenedFile
Currently active file in the editor
getEditorSelection
Selected text or lines in the active editor
getConsoleOutput
Recent Eclipse console output
getMethodCallHierarchy
Call hierarchy (callers) for a method
getTypeHierarchy
Type hierarchy (supertypes, interfaces, subtypes)
findReferences
All references to a type, method, or field across the workspace
getCompilationErrors
Compilation errors from the workspace or a project
getQuickFixes
Available quick fixes for compilation errors
getImportSuggestions
Import candidates for unresolved types
fileSearch
Substring search in workspace files
fileSearchRegExp
Regex search in workspace files
findFiles
Glob pattern file search
searchAndReplace
Search and replace across multiple files
runAllTests
Run all tests in a project
runPackageTests
Run tests in a specific package
runClassTests
Run tests for a specific class
runTestMethod
Run a specific test method
findTestClasses
Classify plain JUnit and *PDETest harness tests; warns about likely PDE-dependent tests that violate the naming convention
runMavenBuild
Run a Maven build the way Run As > Maven build does, with the full Maven log in the console; reports exit code, [ERROR] lines and the log tail
getEffectivePom
Effective POM for a Maven project
getProjectDependencies
Maven project dependencies
getMarkdownOutline
Heading structure (TOC) of a Markdown file with line numbers and section sizes
getMarkdownSection
Read a specific section from a Markdown file by heading name or index
eclipse-runner -- Launch, Debug & Breakpoints
Tool
Description
runJavaApplication
Launch in run mode with optional arguments and timeout
debugJavaApplication
Launch in debug mode, stops at breakpoints
launchConfiguration
Launch an existing saved launch configuration by name (reuses its classpath, VM args, env, working dir, JRebel, etc.) in run or debug mode
listLaunchConfigurations
List saved launch configurations (name, type, project, main class)
stopApplication
Stop a running/debugging application
listActiveLaunches
List all running/debugging applications
toggleBreakpoint
Set or remove a line breakpoint
setConditionalBreakpoint
Breakpoint with condition expression and optional hit count
listBreakpoints
List all breakpoints with status and conditions
removeAllBreakpoints
Remove all breakpoints
getStackTrace
Stack trace of all threads with local variables
evaluateExpression
Evaluate a Java expression in a suspended debug frame
resumeDebug
Resume execution of a suspended session
stepOver
Step over the current line
stepInto
Step into the method call
stepReturn
Step out of the current method
hotCodeReplace
Push code changes into a running debug session without restarting
eclipse-context -- Resource Cache & Local History
Tool
Description
listCachedResources
Lists all resources in the conversation cache -- URIs, types, versions, timestamps, token estimates
getCachedResource
Gets cached resource content by URI without disk I/O
Lists Local History versions of a file with timestamps and sizes
getFileHistoryContent
Reads the content of a specific Local History version
restoreFileVersion
Restores a file to a specific Local History version
compareWithHistory
Shows a unified diff between current content and a historical version
eclipse-git -- Git Operations (EGit)
Tool
Description
gitStatus
Working tree status -- staged, unstaged, untracked files, branch tracking info
gitLog
Commit history from any revision, optionally only the commits touching given project-relative paths
gitShow
One commit with its parents and the diff it introduced, per file and as a unified diff
gitReadFile
Read a UTF-8 text file from HEAD, a branch/tag/commit, or the staged INDEX without changing the working tree
gitDiff
Unified diff of unstaged or staged changes, or between two revisions, with optional project-relative path filters and whitespace-insensitive comparison
gitAdd
Stage project-relative files or folders (comma-separated; '.' for the whole project)
gitStagePatch
Stage selected unified-diff hunks directly into the index without changing the working tree
gitCommit
Commit staged changes; optionally stage every tracked change first (-a) or amend the previous commit
gitReset
Unstage project-relative files from the index
gitDiscardChanges
Restore tracked files from the index, dropping their uncommitted modifications
gitResetToRevision
Move the branch to a revision (soft, mixed or hard) -- undo commits, or abandon a conflicted merge
gitBranch
List branches (local or including remote)
gitCreateBranch
Create a new branch from HEAD or a specified start point
gitDeleteBranch
Delete a branch (with optional force)
gitCheckout
Switch to a branch
gitMerge
Merge a branch, tag or commit; reports fast-forward, merge commit, squash, conflicts or blocking local changes as structured fields
gitRebase
Rebase onto an upstream and drive it through conflicts with CONTINUE, SKIP or ABORT
gitCherryPick
Apply existing commits to the current branch as new commits
gitRevert
Undo existing commits with new reverse commits
gitTag / gitTagList / gitDeleteTag
Create (lightweight or annotated), list and delete tags
gitStash
Stash working directory changes
gitStashPop
Apply and drop the most recent stash
gitStashList
List all stash entries
gitRemoteList
List remotes with their fetch and push URLs
gitFetch
Fetch from a remote and report every remote-tracking ref that moved
gitPull
Fetch and merge, or rebase onto, the upstream; conflicts and blocking changes are reported as files
gitPush
Push a branch, optionally recording it as upstream or forcing; a rejection names the remedy
eclipse-pde -- Plug-in Development
Tool
Description
getActiveTarget
Show the active PDE target platform
setActiveTarget
Load and activate a target definition
reloadTarget
Reload the active target after its contents change
runJUnitPluginTests
Run a plug-in project's tests in the PDE harness
runJUnitPluginTestClass
Run one *PDETest class in the PDE harness
runJUnitPluginTestClasses
Run selected *PDETest classes in one PDE launch, avoiding repeated workbench startup
restartMcpServers
Rebuild HTTP MCP servers after a safe delay so the current response can finish
reloadWorkspaceBundle
Update an OSGi bundle only when backed by an open workspace project; system, fragment, and installed-only bundles are rejected
Tests that use Eclipse workspace, JDT, UI, platform, or OSGi runtime services must follow the *PDETest.java naming convention so test discovery runs them in the PDE harness.
Utility Servers
Server
Tool
Description
duck-duck-search
webSearch
Web search via DuckDuckGo
memory
think
Scratchpad for reasoning without side effects
webpage-reader
readWebPage
Fetch a web page and return it as markdown
time
currentTime
Current date and time
time
convertTimeZone
Convert time between time zones
Configuration
Per-Server Tool Filtering
Each MCP server can have individual tools enabled or disabled to reduce token overhead or exclude irrelevant tools.
Navigate to Window > Preferences > Assist AI > MCP Servers
Select a server (works for both built-in and user-defined)
In the Tools section, uncheck tools you want to exclude
Changes take effect immediately -- both the internal MCP client and the HTTP server restart automatically. Excluded tools won't appear in tools/list responses.
Adding External MCP Servers
AssistAI is also an MCP client -- you can connect external MCP servers (stdio-based) and use their tools through any of the supported LLMs.
Open Window > Preferences > Assist AI > MCP Servers and click Add
Define environment variables if needed (e.g., API keys)
The ${workspace_loc} variable resolves to the workspace folder. Other Eclipse variables are available (${project_loc}, etc.).
Security: MCP servers grant LLMs access to read and modify data. Use them cautiously.
HTTP MCP Server Security
Local network only by default -- only expose externally if necessary
Authentication token -- always use one when exposing beyond localhost
Firewall rules -- allow connections only from trusted sources
HTTPS -- consider a reverse proxy with TLS for production use
Access control -- connected agents have access to all tools on enabled endpoints
AI File Access Control (.aiignore)
AssistAI enforces file-level access restrictions so that sensitive files are never sent to AI models -- whether through the built-in chat or external MCP clients. The AiIgnoreService uses .gitignore-style pattern matching (powered by JGit) to determine which files are excluded.
Per-Project Rules
Place a .aiignore file in the root of any Eclipse project. The syntax follows .gitignore conventions:
# Exclude private keys and certificates
*.pem
*.key
# Exclude secrets directory
secret/
# Exclude all .env files
.env*
# Exclude all properties except application.properties
*.properties
!application.properties
# Exclude credentials anywhere in the tree
**/credentials.json
Disabling AI for an Entire Project
Create an empty .noai file in the project root. When present, all AI access to the project is denied â no pattern matching is performed.
Supported File Names
The service checks for ignore files in this order:
The filename configured in preferences (default: .aiignore)
.aiignore (fallback if a different name is configured)
.aiexclude (legacy fallback)
Pattern Syntax
Pattern
Matches
*.pem
All .pem files
secret/
The secret directory (not a file named secret)
.env*
.env, .env.local, .env.production
!file
Negation - re-includes a previously excluded file
**/name
name at any directory depth
path/to/dir/
A specific directory path
Rules are evaluated in order; the last matching rule wins. Negation patterns (!) can override earlier excludes.
Behavior
Rules are cached per project and automatically reloaded when .aiignore or .noai files change
Excluded files cause MCP tools to throw an AiAccessDeniedException with a descriptive message
Global patterns from preferences are prepended to per-project rules
Built-in Chat View
AssistAI includes a built-in LLM chat panel for direct interaction without external agents. Open it via Window > Show View > Other > Code Assist AI > AssistAI Chat.
Features:
Refactor, document, or generate tests for selected code via context menu
Fix compilation errors with LLM guidance
Discuss code with full file context
Generate git commit messages from staged changes
Drag-and-drop images for vision model discussions
Display images returned by MCP tools as chat attachments
LaTeX and table rendering in responses
In-text code completion with Alt+/
Smart resource caching -- LLM always sees the latest version of attached files
Customizable pre-defined prompts
Switch between models on the fly
Supported Models
Provider
Protocol
Sample Models
MCP / Tools
Vision
OpenAI
OpenAI API
gpt-5
Yes
Yes
Anthropic
Claude API
claude-sonnet-4-5-20250929
Yes
Yes
Google
Gemini API
gemini-2.5-flash, gemini-3-pro-preview
Yes
Yes
Grok
Grok API
grok-4, grok-code-fast
Yes
Yes
Groq
OpenAI API
qwen-qwq-32b, llama3-70b-8192
Yes
Yes
DeepSeek
DeepSeek API
deepseek-chat
Yes
No
Local/Self-hosted
OpenAI API
Ollama, LM Studio, etc.
Varies
Varies
Other 3rd party
OpenAI API
Together.ai, Anyscale, etc.
Varies
Varies
Configure models in Window > Preferences > Assist AI > Models.
Screenshots
claude-code controlling the Eclipse IDE via MCP
Agentic coding with Eclipse MCP tools
Discussing code in the built-in chat
Refactoring selected code
Generating documentation
Generating JUnit tests
Git commit message generation
Fixing compilation errors with patches
Tool calls for context-aware answers
Vision model -- discuss images
LaTeX and table rendering
Configuring MCP servers
Installation
Eclipse Marketplace
Drag the button below into your running Eclipse workspace:
Update Site
In Eclipse, open Help > Install New Software
Click Add, enter AssistAI as Name and https://gradusnikov.github.io/eclipse-chatgpt-plugin/ as Location
Select "Assist AI" from the plugin list and proceed through the wizard
Accept certificate warnings (self-signed plugin)
Initial Setup
Open Window > Preferences > Assist AI
Configure your models in Preferences > Assist AI > Models
To use with external agents, enable the HTTP MCP Server (see above)
