Convex Doctor Skill

Run through these checks when writing or reviewing Convex backend and client code. Based on the convex-doctor CLI which scores projects 0-100 across 72 rules in 7 categories.

How to use this skill

1. Before shipping backend changes, scan the affected files against the rules below.
2. Flag violations by severity: error (must fix), warning (should fix), info (consider fixing).
3. Suggest the fix inline when flagging.
4. If the user has convex-doctor installed, recommend running npx convex-doctor -v for a full report.

Security (13 rules, 1.5x weight)

ID	Severity	Rule
missing-arg-validators	error	All query/mutation/action and internal variants must have args validators
missing-return-validators	warning	Public functions should have returns validators
missing-auth-check	warning	Public functions should call ctx.auth.getUserIdentity()
internal-api-misuse	error	Server-to-server calls must use internal.*, not api.*
hardcoded-secrets	error	No API keys, tokens, or secrets hardcoded in source
env-not-gitignored	error	.env.local must be in .gitignore
spoofable-access-control	warning	Do not trust client args like userId or role for access control
missing-table-id	warning	Use v.id("table") instead of v.string() for document references
missing-http-auth	error	HTTP action endpoints must include authentication
conditional-function-export	error	Do not conditionally export Convex functions based on environment
generic-mutation-args	warning	Do not use v.any() in public mutation args
overly-broad-patch	warning	Do not ctx.db.patch with spread args that bypass validation
http-missing-cors	warning	HTTP routes should include CORS headers

Performance (13 rules, 1.2x weight)

ID	Severity	Rule
unbounded-collect	error	.collect() without .take(n) limit
filter-without-index	warning	.filter() scanning entire tables instead of using .withIndex()
date-now-in-query	error	Date.now() in query functions breaks caching
loop-run-mutation	error	ctx.runMutation/ctx.runQuery inside loops (N+1)
sequential-run-calls	warning	Multiple sequential ctx.run* calls in an action
unnecessary-run-action	warning	ctx.runAction from within an action (same runtime)
helper-vs-run	warning	ctx.runQuery/ctx.runMutation inside a query or mutation
missing-index-on-foreign-key	warning	v.id("table") schema field without a corresponding index
action-from-client	warning	Client calling actions directly instead of mutations
collect-then-filter	warning	.collect() followed by JS .filter() instead of DB query filters
large-document-write	info	Inserting documents with 20+ fields
no-pagination-for-list	warning	Public query with .collect() returning unbounded results
missing-pagination-opts-validator	warning	.paginate(...) without paginationOptsValidator in args

Correctness (20 rules, 1.5x weight)

ID	Severity	Rule
unwaited-promise	error	ctx.db.insert, ctx.runMutation, etc. without await
old-function-syntax	warning	Legacy function registration syntax
db-in-action	error	Direct ctx.db.* calls inside actions
deprecated-api	warning	Deprecated APIs like v.bigint()
wrong-runtime-import	warning	Incompatible runtime imports
direct-function-ref	warning	Direct function refs instead of api.*/internal.*
missing-unique	warning	.first() where .unique() is appropriate
query-side-effect	error	Side effects (ctx.db.insert/patch/delete) inside queries
mutation-in-query	error	ctx.runMutation from within a query
cron-uses-public-api	error	Cron jobs referencing api.* instead of internal.*
node-query-mutation	error	Queries/mutations in "use node" files
scheduler-return-ignored	info	ctx.scheduler.runAfter return value not captured
non-deterministic-in-query	warning	Math.random(), new Date(), crypto in queries
replace-vs-patch	info	ctx.db.replace semantics reminder
generated-code-modified	error	Manual edits to _generated/ files
unsupported-validator-type	error	Unsupported validators (v.map(), v.set())
query-delete-unsupported	error	.delete() on query chains
cron-helper-method-usage	warning	Deprecated crons.hourly/daily/weekly
cron-direct-function-reference	error	Direct function identifiers in cron methods
storage-get-metadata-deprecated	warning	Deprecated ctx.storage.getMetadata

Schema (9 rules, 1.0x weight)

ID	Severity	Rule
missing-schema	warning	No schema.ts in convex/
deep-nesting	warning	Validators nested more than 3 levels deep
array-relationships	warning	v.array(v.id(...)) that may grow unbounded
redundant-index	warning	Index that is a prefix of another on the same table
too-many-indexes	info	Table with 8+ indexes
missing-search-index-filter	info	Search index without filterFields
optional-field-no-default-handling	warning	5+ optional fields without undefined handling
missing-index-for-query	warning	Query filters on a field with no matching index
index-name-includes-fields	warning	Index name does not include all indexed fields in order

Architecture (8 rules, 0.8x weight)

ID	Severity	Rule
large-handler	warning	Handler exceeding 50 lines
monolithic-file	warning	File with 10+ exported functions
duplicated-auth	warning	3+ inline auth checks in the same file
action-without-scheduling	info	Action that could use ctx.scheduler instead
no-convex-error	info	throw new Error(...) instead of throw new ConvexError(...)
mixed-function-types	info	File mixing public and internal exports
no-helper-functions	info	Multiple large handlers with no shared helpers
deep-function-chain	warning	Action with 5+ ctx.run* calls

Configuration (5 rules, 1.0x weight)

ID	Severity	Rule
missing-convex-json	warning	No convex.json in project root
missing-auth-config	error	Functions use ctx.auth but no auth.config.ts exists
missing-generated-code	warning	No _generated/ directory
outdated-node-version	warning	Node version in config is outdated
missing-tsconfig	info	No tsconfig.json in convex directory

Client-Side (4 rules, 1.0x weight)

ID	Severity	Rule
mutation-in-render	error	Mutation invocation during render
unhandled-loading-state	warning	useQuery result used without checking for undefined
action-instead-of-mutation	info	useAction where useMutation may suffice
missing-convex-provider	info	Convex hooks without ConvexProvider in component tree

Scoring

Health score is 0-100. Each finding deducts points based on severity and category weight, with per-rule caps.

Score	Label	Meaning
85-100	Healthy	Few or no issues
70-84	Needs attention	Some issues worth addressing
50-69	Unhealthy	Significant problems
0-49	Critical	Serious issues requiring immediate attention

Common fix patterns

Replace .filter() with .withIndex()

// Bad
const docs = await ctx.db.query("tasks").filter((q) => q.eq(q.field("userId"), userId)).collect();

// Good (add index "by_userId" on ["userId"] in schema)
const docs = await ctx.db.query("tasks").withIndex("by_userId", (q) => q.eq("userId", userId)).collect();

Replace loop mutations with batch

// Bad
for (const id of ids) {
  await ctx.runMutation(internal.tasks.complete, { taskId: id });
}

// Good: single mutation that handles the batch
const updates = ids.map((id) => ctx.db.patch(id, { completed: true }));
await Promise.all(updates);

Fix Date.now() in queries

// Bad (in a query)
const cutoff = Date.now() - 86400000;

// Good: pass timestamp as an argument from the caller
args: { cutoff: v.number() },

Fix unbounded collect

// Bad
const all = await ctx.db.query("messages").collect();

// Good: paginate or limit
const recent = await ctx.db.query("messages").order("desc").take(50);

CLI reference

npx convex-doctor        # basic scan
npx convex-doctor -v     # verbose with file paths and line numbers
npx convex-doctor --format json  # JSON output for CI
npx convex-doctor --score        # score only (prints a number)
npx convex-doctor --diff main    # only files changed vs base branch

Source: https://github.com/nooesc/convex-doctor