Convex

Convex backend skill with a bias toward safety, observability, and index-backed queries.

Docs-First Rule (Blocking)

Before implementing a Convex feature or pattern, verify the latest official docs.

Primary sources:

• https://docs.convex.dev/
• https://stack.convex.dev/

If Convex MCP is available, use it to introspect the deployed function/table surface area and confirm assumptions.

Environments (Dev / Preview / Prod)

Convex projects typically have:

• Dev deployments (your local npx convex dev sync target)
• Preview deployments (branch/PR deployments, beta feature)
• Production deployment

Use MCP status (if available) or the CLI to confirm which deployment you are connected to before making changes.

Components-First Rule

Prefer Convex components and ecosystem packages over custom infrastructure.

Start at:

• https://docs.convex.dev/components
• references/ecosystem.md

Core Rule (Blocking)

Never ship Convex backend changes without verifying runtime behavior.

Preferred verification order:

1. Convex MCP logs (structured, diffable)
2. npx convex dev terminal logs
3. Convex Dashboard logs

Project Conventions (Preferred)

• Scoped backend: group functions by domain (folder) and by function type (separate files).
• Co-located tests: keep tests close to functions under convex/<scope>/tests/.
• Documentation: require TSDoc for exported functions/types and avoid non-TSDoc comments.

See references/style.md and references/testing.md.

Router

User says	Load reference	Do
help / cli help / usage	references/cli-help.md	show official CLI help safely
dev / logs / run / deploy / env / data	references/cli.md	common CLI workflows
mcp / tools / introspect / logs	references/mcp.md	use Convex MCP tools
tsdoc / docs / style	references/style.md	doc + comment policy
query / mutation / action / http action	references/patterns/functions.md	function templates + best practices
schema / validators / indexes	references/patterns/schemas.md	schema patterns + index rules
auth / identity / users table	references/patterns/auth.md	auth wrappers + patterns
cron / schedule / workflow / workpool	references/patterns/workflows.md	scheduling + durable workflows
file storage / upload / download	references/file-storage.md	file storage patterns
http / webhook	references/patterns/http.md	httpRouter/httpAction patterns
testing	references/testing.md	testing patterns
ecosystem / components	references/ecosystem.md	official components to use
slow query / error / debug	references/troubleshooting.md	troubleshooting + anti-patterns
validate / checklist	checklists/validation.md	blocking checks before shipping

MCP Integration (Recommended)

If Convex MCP is available, use it first.

If Convex MCP is not available, this skill still works:

• Use the Convex CLI (npx convex ...) and the dashboard.

• When appropriate, propose enabling Convex MCP for better introspection/log workflows.

• Discover deployments: convex_status({ projectDir })

• Inspect functions: convex_functionSpec({ deploymentSelector })

• Inspect tables: convex_tables({ deploymentSelector })

• Read data: convex_data({ deploymentSelector, tableName, ... })

• Run functions: convex_run({ deploymentSelector, functionName, args })

• Run safe ad-hoc reads: convex_runOneoffQuery({ deploymentSelector, query })

• Verify logs: convex_logs({ deploymentSelector, ... })

Full workflow: references/mcp.md.

Critical Rules (7)

1. Always use validators (args + returns) for functions.
2. Always use explicit table names with ctx.db.get/patch/replace.
3. Prefer index-backed queries (withIndex) and bounded reads (take/pagination).
4. User identity comes from ctx.auth, never from args.
5. Use internal* functions for sensitive operations.
6. Schedule only internal functions.
7. Use v.null() for void returns (return null).

References

• Patterns:
  • references/patterns/schemas.md
  • references/patterns/functions.md
  • references/patterns/auth.md
  • references/patterns/workflows.md
  • references/patterns/http.md
• Other:
  • references/mcp.md
  • references/cli.md
  • references/cli-help.md
  • references/style.md
  • references/file-storage.md
  • references/testing.md
  • references/ecosystem.md
  • references/troubleshooting.md
• Checklist:
  • checklists/validation.md