MCP Provider

The MCP provider connects Colin to Model Context Protocol servers. Through MCP, your documents can fetch live data from project trackers, databases, code repositories, and other systems. Colin acts as an MCP client, connecting to configured servers and fetching resources during compilation. Each configured MCP server becomes a separate provider instance with its own namespace. Configure a server named “github” and it becomes accessible as colin.mcp.github in templates.

Configuration

MCP providers require a name field—there is no default MCP provider. Each entry in colin.toml defines a named server instance:

colin.toml

[[providers.mcp]]
name = "github"
command = "uvx"
args = ["mcp-server-github"]

[[providers.mcp]]
name = "linear"
command = "npx"
args = ["-y", "@linear/mcp-server"]

The name field determines the template namespace. A server named github becomes accessible as colin.mcp.github, while linear becomes colin.mcp.linear. Colin starts server processes when entering the provider lifespan and terminates them on shutdown.

Field	Description
`name`	Required. Identifier used in templates as `colin.mcp.<name>`
`command`	Executable to run for stdio servers
`args`	Command-line arguments as an array
`env`	Environment variables passed to the server
`url`	Server endpoint URL for remote servers
`headers`	HTTP headers for remote server authentication

Stdio Servers

Local process servers communicate via stdin/stdout. Specify the executable and arguments:

colin.toml

[[providers.mcp]]
name = "filesystem"
command = "npx"
args = ["@anthropic/mcp-server-filesystem", "/path/to/data"]

Pass credentials and configuration through environment variables:

colin.toml

[[providers.mcp]]
name = "postgres"
command = "npx"
args = ["@anthropic/mcp-server-postgres"]
env = { DATABASE_URL = "postgres://user:pass@localhost/db" }

Reference shell environment variables with ${VAR} syntax. Colin substitutes values from your environment when starting the server:

colin.toml

[[providers.mcp]]
name = "github"
command = "uvx"
args = ["mcp-server-github"]
env = { GITHUB_TOKEN = "${GITHUB_TOKEN}" }

Remote Servers

HTTP and SSE servers connect over the network instead of spawning a local process:

colin.toml

[[providers.mcp]]
name = "remote-api"
url = "https://api.example.com/mcp"

For servers requiring authentication:

colin.toml

[[providers.mcp]]
name = "authenticated"
url = "https://api.example.com/mcp"
headers = { Authorization = "Bearer ${API_TOKEN}" }

Template Functions

Each MCP server exposes these functions through its namespace:

Function	Purpose
`resource()`	Fetch a resource from the server
`list_resources()`	List available resources
`list_skills()`	Discover skills from skill servers
`prompt()`	Retrieve a prompt template from the server
`list_tools()`	List available tools
`server_info()`	Get server metadata

Resource

Use colin.mcp.<name>.resource() to fetch content from a server:

models/sources/readme.md

---
name: GitHub README
---

{{ colin.mcp.github.resource('repo://owner/repo/contents/README.md') }}

The function returns an MCPResource object with content and metadata:

Property	Description
`.content`	The resource content as a string
`.name`	Resource name from the server
`.uri`	Full MCP URI for tracking
`.description`	Optional description from server
`.updated`	Last update timestamp

Access properties directly:

{% set readme = colin.mcp.github.resource('repo://owner/repo/contents/README.md') %}

# {{ readme.name }}

{{ readme.content }}

Each MCP server defines its own URI scheme. Consult the server’s documentation for available resources:

{# GitHub server #}
{{ colin.mcp.github.resource('repo://owner/repo/contents/README.md') }}
{{ colin.mcp.github.resource('repo://owner/repo/issues') }}

{# Linear server #}
{{ colin.mcp.linear.resource('projects') }}
{{ colin.mcp.linear.resource('issues?teamId=TEAM-123') }}

{# Filesystem server #}
{{ colin.mcp.filesystem.resource('file:///data/config.json') }}

{# Postgres server #}
{{ colin.mcp.postgres.resource('query://SELECT * FROM users LIMIT 10') }}

Prompt

Some MCP servers provide prompt templates. Use colin.mcp.<name>.prompt() to retrieve them:

models/analysis.md

---
name: Code Analysis
---

{% set review = colin.mcp.github.prompt('code-review', repo='owner/repo') %}
{{ review.content }}

The function returns an MCPPrompt object with similar properties to MCPResource. Prompt arguments are passed as keyword parameters after the prompt name.

List Resources

Use colin.mcp.<name>.list_resources() to discover available resources from a server:

{% set resources = colin.mcp.github.list_resources() %}
{% for r in resources %}
- {{ r.uri }}: {{ r.description or "No description" }}
{% endfor %}

Returns a list of MCPResourceInfo objects with lightweight metadata (no content fetched):

Property	Type	Description
`uri`	`str`	Full MCP URI
`name`	`str \| None`	Resource name
`description`	`str \| None`	Optional description
`mime_type`	`str \| None`	MIME type

List Skills

For MCP servers that serve skills using the skill:// scheme (like FastMCP skill servers), use list_skills() to discover and download skills:

{% for skill in colin.mcp.source.list_skills() %}
# {{ skill.name }}
{{ skill.description or "No description" }}

Files:
{% for file in skill.files %}
- {{ file.path }}{% if file.hash %} ({{ file.hash[:8] }}){% endif %}
{% endfor %}
{% endfor %}

This method:

Finds resources matching skill://{name}/SKILL.md
Fetches manifests from skill://{name}/_manifest
Returns SkillInfo objects with file lists

Property	Type	Description
`name`	`str`	Skill identifier
`description`	`str \| None`	Skill description
`files`	`list[SkillFileInfo]`	Files in the skill

Each SkillFileInfo has:

Property	Type	Description
`path`	`str`	Relative file path
`hash`	`str \| None`	Content hash for change detection

Use list_skills() with resource() to download skill content:

{% for skill in colin.mcp.source.list_skills() %}
{% for file in skill.files %}
{% file skill.name ~ "/" ~ file.path %}
{{ colin.mcp.source.resource('skill://' ~ skill.name ~ '/' ~ file.path).content }}
{% endfile %}
{% endfor %}
{% endfor %}

Objects

The MCP provider introduces these domain objects: MCPResource - Returned by resource():

Property	Type	Description
`uri`	`str`	Full MCP URI
`content`	`str`	Resource content
`name`	`str`	Resource name
`description`	`str \| None`	Optional description

MCPPrompt - Returned by prompt():

Property	Type	Description
`content`	`str`	Prompt content
`name`	`str`	Prompt name
`arguments`	`dict`	Arguments passed to the prompt
`description`	`str \| None`	Optional description

MCPResourceInfo - Returned by list_resources():

Property	Type	Description
`uri`	`str`	Full MCP URI
`name`	`str \| None`	Resource name
`description`	`str \| None`	Optional description
`mime_type`	`str \| None`	MIME type

SkillInfo - Returned by list_skills():

Property	Type	Description
`name`	`str`	Skill identifier
`description`	`str \| None`	Skill description
`files`	`list[SkillFileInfo]`	Files in the skill

SkillFileInfo - Files within a skill:

Property	Type	Description
`path`	`str`	Relative file path
`hash`	`str \| None`	Content hash

Dependency Tracking

MCP resources integrate with Colin’s dependency system. Wrap results with ref() to record dependencies in the manifest:

{# Fetched but not tracked #}
{{ colin.mcp.github.resource('repo://...').content }}

{# Tracked as a dependency #}
{{ ref(colin.mcp.github.resource('repo://...')).content }}

The manifest records MCP resources as standard refs:

{
  "documents": {
    "sources/readme": {
      "refs_evaluated": ["mcp.github://?resource=repo%3A%2F%2Fowner%2Frepo%2Fcontents%2FREADME.md"]
    }
  }
}

CLI Commands

The CLI provides commands for MCP server management:

# Add a server
colin mcp add github uvx mcp-server-github

# List configured servers
colin mcp list

# Test server connectivity
colin mcp test github

# Remove a server
colin mcp remove github

The test command starts the server and lists available resources, helping discover the correct URIs for your documents.

Combining Sources

MCP resources work alongside other providers and local documents:

models/skills/engineering-status.md

---
name: Engineering Status
---

# Engineering Status

## Active Projects

{{ colin.mcp.linear.resource('projects?team=engineering') }}

## Repository Health

{% set issues = colin.mcp.github.resource('repo://acme/platform/issues?state=open') %}
{{ issues.content }}

## Analysis

{% llm %}
Based on the project data and open issues, assess team health:

Projects:
{{ colin.mcp.linear.resource('projects?team=engineering') }}

Issues:
{{ issues.content }}

Provide velocity assessment, blockers, and priorities.
{% endllm %}

Get Started

Projects

Providers

Renderers

Running Colin

MCP Provider

Configuration

Stdio Servers

Remote Servers

Template Functions

Resource

Prompt

List Resources

List Skills

Objects

Dependency Tracking

CLI Commands

Combining Sources

Get Started

Projects

Providers

Renderers

Running Colin

​Configuration

​Stdio Servers

​Remote Servers

​Template Functions

​Resource

​Prompt

​List Resources

​List Skills

​Objects

​Dependency Tracking

​CLI Commands

​Combining Sources

Configuration

Stdio Servers

Remote Servers

Template Functions

Resource

Prompt

List Resources

List Skills

Objects

Dependency Tracking

CLI Commands

Combining Sources