sling

name

sling

description

Sling data platform — overview, MCP tools such as querying databases, CLI quick reference, connection setup, project layout, and troubleshooting. Use when asked to query databases via mcp, about Sling in general, what it does, how to use the MCP tools, when setting up or testing connections and credentials, when starting a project or choosing folders, or when debugging errors, connection failures, authentication issues, type conversion problems, memory/performance issues, or API rate limits.

Sling - Data Integration Platform

Move data between 40+ databases, file systems, and APIs with a single CLI.

When to Use Sling

Use Case	Solution
Move data between databases	Replication (DB-to-DB)
Load files into databases	Replication (file-to-DB)
Export data to files	Replication (DB-to-file)
Extract API data	Replication (API-to-DB/file)
Log-based change capture (CDC)	Replication (mode: change-capture) — see sling-replications skill
Multi-step workflows	Pipelines
Build SQL models	sling build
Drive Sling from Python	pip install sling — see the sling-python skill
Hosted jobs / scheduling	Sling Platform

MCP Tools Reference

Tool	Actions	Use Case
connection	list, test, discover, set	Manage connections
database	query, query_cancel, get_schemata	Inspect/query databases
file_system	list, copy, inspect	Browse/copy files
replication	docs, validate	Validate replication configs
pipeline	docs, validate	Validate pipeline configs
api_spec	docs, validate, test	Build API integrations

The Sling CLI stdio MCP has no run, build, or report action. Execute with the CLI: sling run (replications/pipelines), sling build (SQL models), and sling assist report (issue reports). The Platform HTTP MCP is separate; its jobs.trigger runs hosted jobs, not local files.

After you classify a failure as a sling defect (not user config), offer: "Report this? GitHub issue (public, needs account) or email to support." Never offer this for user-config errors. Send only after the user agrees. Show the user the draft first (sling assist report --id <id>), then send with --github or --email. Add --submit to skip the interactive confirm (for agents and non-TTY use). --email opens the contact page with the report prefilled; the user fills in their name and email there — do not ask for an email address yourself.

Improve the report before sending: pass --title "<plain-English summary>" (the default title is a terse error label, e.g. did_not_find_any_columns_for_ident_ident; write what a maintainer would search for, e.g. "Incremental replication fails when source table has no columns") and --description "<context>" (what you tried, what you expected, what happened; it appears above the raw error). Example:

sling assist report --id <id> --github --submit \
  --title "Incremental replication fails when source table has no columns" \
  --description "Replication from Postgres to ClickHouse fails on the first stream. The source table exists and the user can select from it."

Quick Examples

// List connections
{"action": "list", "input": {}}

// Test connection
{"action": "test", "input": {"connection": "MY_CONN", "debug": true}}

// Validate a replication (compile is the default)
{"action": "validate", "input": {"file_path": "/path/to/replication.yaml"}}

CLI vs MCP — which to use

Use the MCP tools to inspect and validate. Use the CLI to execute.

Task	Use
Ad-hoc SQL query, schema lookup	MCP database (query, get_schemata, get_columns)
List, test, or discover connections	MCP connection
Browse, inspect, or copy files	MCP file_system
Validate a replication, pipeline, or API spec	MCP replication / pipeline / api_spec
Execute a replication or pipeline	CLI sling run
Build SQL models	CLI sling build
Send an issue report	CLI sling assist report

Do not query a database with sling run --stdout. That flag is for piping data to a target, not for inspecting a database. Use the MCP database tool.

When the MCP tools are not available, query with sling conns exec:

sling conns exec MY_PG "select * from public.users limit 10"
sling conns exec MY_PG "select 1" -o json      # Output: text (default), csv, json, arrow

CLI Quick Reference

sling conns list                    # List connections
sling conns test MY_CONN --debug    # Test connection
sling conns discover MY_PG          # Discover tables
sling conns exec MY_PG "select 1"   # Run a SQL query (add -o json|csv|arrow)
sling run -r replication.yaml       # Run replication
sling run -p pipeline.yaml          # Run pipeline
sling run -r replication.yaml --debug   # Run with debug logging
sling build                         # Run SQL models
sling build --compile               # Compile models without executing
sling assist --id <id>              # Investigate a failure (id from the error footer)
sling assist error <sig>            # Look up an error signature (from prompt context)
sling assist report --id <id>       # Review a redacted issue report
sling assist                        # Open assist (offers to investigate failures)

Topics Reference

Topic	Description
TROUBLESHOOTING.md	Common errors: connections, auth, type conversion, memory, API rate limits, performance
CONNECTIONS.md	Set up, test, and discover connections; secrets boundary; per-connector docs
PROJECT.md	Canonical project layout, the four warehouse layers, and where each file goes

Documentation Map

Append .md paths to https://docs.slingdata.io to fetch raw markdown. Full index: https://docs.slingdata.io/llms.txt

Topic	Doc
Replications	https://docs.slingdata.io/concepts/replication.md
Build (SQL models)	https://docs.slingdata.io/concepts/build.md
Change capture (CDC)	https://docs.slingdata.io/concepts/change-capture.md
API specs	https://docs.slingdata.io/concepts/api-specs.md
Hooks / steps	https://docs.slingdata.io/concepts/hooks.md
Pipelines	https://docs.slingdata.io/concepts/pipeline.md
Data quality constraints	https://docs.slingdata.io/concepts/data-quality.md
Functions	https://docs.slingdata.io/concepts/functions.md
Env vars (SLING_STATE, SLING_THREADS, ...)	https://docs.slingdata.io/sling-cli/environment.md
CLI usage (sling run, flags)	https://docs.slingdata.io/sling-cli/run.md
CLI Pro	https://docs.slingdata.io/sling-cli/cli-pro.md
Platform	https://docs.slingdata.io/sling-platform/platform.md
Connections (per-connector guides)	https://docs.slingdata.io/connections/ — see CONNECTIONS.md

Documentation

• Official Docs: https://docs.slingdata.io
• GitHub: https://github.com/slingdata-io/sling-cli
• Discord: https://discord.gg/q5xtaSNDvp