Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@effect-mcp how do I use Effect.sync?"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
A Model Context Protocol (MCP) server dedicated to fetching the most current documentation from the Effect ecosystem.
This MCP server provides real-time access to Effect documentation for AI assistants and tools. It enables VS Code extensions and other MCP clients to retrieve accurate and up-to-date Effect package documentation to assist developers with questions about:
The core effect package
Ecosystem packages (@effect/platform, @effect/ai, etc.)
Both stable and unstable Effect packages
The server intelligently detects imported Effect packages in your code and fetches the most relevant documentation to answer your queries.
Related MCP server: MCP Documentation Server
Real-time documentation access for Effect ecosystem
Support for both stable and experimental packages
Context-aware package detection based on imports
Seamless integration with VS Code and other MCP-compatible clients
Helps answer API usage questions for Effect developers
Resources (preferred)
Dynamic template: effect-docs://{libId}
Completions on {libId} and resource listing are supported
Static aliases for discovery: effect-docs://effect, effect-docs://@effect-platform, etc.
Supported libraries (as of now):
effect
@effect/platform
@effect/sql
@effect/vitest
@effect/ai
@effect/cli
@effect/cluster
@effect/rpc
@effect/typeclass
Tools (for compatibility)
effect-documentation: fetch docs for selected libraries and return concatenated markdown
effect-doc-links: return plain URIs to the resources above so clients can follow them
Caching & Retry
In-memory TTL cache (~10 minutes) to avoid refetching unchanged docs.
Lightweight retry with small backoff on transient fetch errors.
pnpm add @niklaserik/effect-mcpFor usage in VS Code or other MCP clients, refer to the client's documentation for adding custom MCP servers.
Quick test locally:
pnpm install
pnpm build
node dist/index.js # stdio transportThen connect with an MCP client (e.g., MCP Inspector) over stdio and try:
List resources and read effect-docs://effect
Call tool effect-doc-links with { "libraries": ["effect", "@effect/platform"] }
Initialization instructions
The server publishes short usage instructions via MCP initialize for clients that display them.
# Install dependencies
pnpm install
# Build the project
pnpm build
# Run in development mode with auto-reload
pnpm devNotes:
Built with @modelcontextprotocol/sdk@^1.17.4 using the modern registerResource/registerTool APIs.
Transport: stdio by default; can be adapted to Streamable HTTP if needed.
MIT
Returns resource links for the specified libraries so the client can load only what's needed.
| Name | Required | Description | Default |
|---|---|---|---|
| libraries | Yes | Effect libraries to reference. E.g. effect, @effect/platform, @effect/sql, @effect/vitest |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It conveys that it is a read-only operation returning links, but does not disclose details like return format, potential side effects, or limitations. The description adds some context about client-side selective loading, but lacks depth.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, front-loaded sentence with no redundant wording. It efficiently communicates the tool's purpose.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description covers the essential behavior of returning links, which is sufficient for a simple query tool with one parameter. However, it does not detail the return structure or explicitly address the sibling tool, leaving minor gaps in completeness.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema fully describes the 'libraries' parameter with examples, giving 100% coverage. The description adds no additional meaning about parameters, so it remains at the baseline for schema-covered parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool returns resource links for specified libraries, with a specific verb and resource. However, it does not explicitly distinguish itself from the sibling tool 'effect-documentation', which would merit a 5.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'so the client can load only what's needed' implies a use case for selective loading, but there is no explicit guidance on when to use this tool instead of the sibling. No alternatives or exclusions are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Fetches and concatenates the latest docs for the specified Effect libraries.
| Name | Required | Description | Default |
|---|---|---|---|
| libraries | Yes | List of Effect libraries. E.g. effect, @effect/platform, @effect/sql, @effect/vitest |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full responsibility for behavioral disclosure. It states that docs are fetched and concatenated, but omits important traits such as whether authentication is needed, any rate limits, output size or format, and whether the operation is read-only. The minimal behavior described is too shallow for an external-fetching tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence that efficiently conveys the core purpose. There is no unnecessary detail, redundancy, or fluff. It is concise and front-loaded with the most important action.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool has a simple one-parameter schema, but there is no output schema and no annotations. The description does not explain what the concatenated output looks like, which could be critical for agents expecting to parse docs. It also does not clarify the relationship with the sibling tool. Given the overall simplicity, the description is minimally adequate but leaves gaps.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema has 100% coverage for its single parameter 'libraries' with a clear description and examples. The tool description adds context that the libraries refer to Effect libraries but does not add any additional parameter meaning beyond what the schema already provides. Therefore a baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's verb ('Fetches and concatenates') and resource ('latest docs for the specified Effect libraries'). It includes a specific scope ('Effect libraries') and differentiates from the sibling 'effect-doc-links' by emphasizing concatenation of documents rather than just providing links.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is provided on when to use this tool vs. the sibling 'effect-doc-links' or any alternative. The description does not mention prerequisites, intended scenarios, or exclusions. Usage must be inferred entirely from the tool's name and description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections. Dates show when Glama detected each change.
v1.0.7effect-doc-linkseffect-documentationThe two tools have clearly distinct purposes: one fetches and returns the actual documentation content, while the other returns resource links for the client to load. There is no overlap or ambiguity between them.
Both tools follow the same 'effect-[noun]' naming pattern with descriptive, hyphenated names. The convention is consistent and predictable.
With only two tools, the server feels thin and borderline for a documentation-focused MCP. The tools are useful, but the count is at the low end of what is considered appropriate.
The server covers the two primary operations for documentation access: fetching content and obtaining links. However, it lacks discovery tools (e.g., listing available libraries) which represents a minor gap depending on the client's needs.
Unclaimed servers have limited discoverability.
If you are the server author, to access and configure the admin panel.
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