ngql-preview

name

ngql-preview

description

**Preview build of the NGql Skill.** Tracks the latest preview release of NGql — content here may reference library APIs that have not yet shipped to the stable `ngql` channel. Use this if you're testing an upcoming NGql release; otherwise install `ngql` (stable). Translates the user's GraphQL intent into NGql query-builder C# code: triggered by "build a query", a pasted GraphQL operation or curl that needs porting to NGql, "filter / preserve fields", or mentions of QueryBuilder / Mutation / PreservationBuilder / NGql. NGql is a zero-dependency, schema-less .NET GraphQL query builder — the user supplies the schema knowledge (field names, types), the Skill produces the fluent code.

NGql Skill

Generate NGql query-builder C# from natural language, pasted GraphQL/curl, or a refactor request. You don't own the schema — render the user's intent, never invent fields.

Three modes

Trigger	Action
Natural language ("get top 10 repos…")	Generate a builder. Well-known APIs (GitHub, Stripe, public schemas) → assume + flag in one line. Unknown APIs → ask for field/arg names first.
Pasted GraphQL or curl	Port verbatim — preserve operation name and variable types. Curl bodies are usually {"query":"…","variables":{…}} JSON; extract first.
Refactor / preserve	Use PreservationBuilder.Create(src).Preserve("a","b").Build(). Preserve is inclusive — for "drop X" requests, list everything except X.

If the mode isn't obvious, ask before generating.

API surface

using NGql.Core;            // Variable, EnumValue, MergingStrategy
using NGql.Core.Builders;   // QueryBuilder, FieldBuilder, PreservationBuilder

// Operations
QueryBuilder.CreateDefaultBuilder("Op");                                       // query
QueryBuilder.CreateMutationBuilder("Op");                                      // mutation
QueryBuilder.CreateDefaultBuilder("Op", MergingStrategy.MergeByFieldPath);     // optional strategy

MergingStrategy controls Include(other) behavior: MergeByDefault (inherit), MergeByFieldPath (merge, auto-alias on arg conflict), NeverMerge.

AddField — these are the only shapes to use

.AddField("path.to.field")                                            // simple, dot-paths nest
.AddField("users", new Dictionary<string, object?> { … })             // args
.AddField("users", new[] { "id", "name" })                            // sub-fields
.AddField("users", new Dictionary<string, object?> { … },             // args + sub-fields (args FIRST)
                   new[] { "id", "name" })
.AddField("user", b => b.AddField("name").AddField("email"))          // sub-field lambda
.AddField("user", new Dictionary<string, object?> { … },              // args + lambda
                   b => b.AddField("name"))
.AddField("amount", "Money!")                                         // typed leaf (rare)

Inside a lambda, call the same shapes on b. Args go BEFORE sub-fields, same as outside.

Variables, enums, fragments, metadata

var idVar = new Variable("$id", "ID!");                               // $-prefix required
.AddField("user", new Dictionary<string, object?> { ["id"] = idVar }, // auto-promotes to op signature
                   new[] { "name" })

.AddField("users", new Dictionary<string, object?> {
    ["role"] = new EnumValue("ADMIN")                                 // unquoted on wire: role:ADMIN
})

// Inline fragment for union/interface narrowing — renders `... on Type { … }`
.AddField("nodes", n => n.OnType("Repository", r => r.AddField("name")))

// Metadata — via lambda + WithMetadata, NEVER as a positional dict
.AddField("user", new Dictionary<string, object?> { ["id"] = idVar }, b => b
    .WithMetadata(new Dictionary<string, object> { ["cached"] = true })
    .AddField("name"))

PreservationBuilder

PreservationBuilder.Create(src).Preserve("user.name", "user.email").Build();
PreservationBuilder.Create(src).PreserveAtPath("createdAt", "user.posts").Build();
PreservationBuilder.Create(src).PreserveFromExpression<UserDto>(x => x.user.email != null).Build();

Build() returns a fresh QueryBuilder; the source is never mutated. The T for PreserveFromExpression<T> must mirror the query shape — don't synthesize the DTO without seeing it or being told.

Composition

QueryBuilder.CreateDefaultBuilder("Combined", MergingStrategy.MergeByFieldPath)
    .Include(fragmentA)
    .Include(fragmentB);

Don't generate

• IDictionary<string, object?> literals — overloads take Dictionary<string, object?>
• using directives for namespaces you don't reference (and never the auto-imports — see snippet contract)
• try/catch, feature flags, or "future-proofing" — let bad input throw
• Code comments unless asked
• GraphQL alongside the C# unless asked — use ngql to render
• var query = …; followed by anything — the snippet must end in a bare expression, never a statement. Drop the var and let the builder be the last expression.
• Console.WriteLine(…) — ngql calls .ToString() itself. Adding Console.WriteLine either won't run or duplicates output. If the user asks for "a complete program" rather than an ngql snippet, that's a different request — confirm before generating it.
• return …; at the script root — Roslyn scripts disallow it. The bare expression is the return.

Value types

In the C# snippet (argument literals)

GraphQL	CLR	Renders
Int	int/long/short (& unsigned)	42
Float	float/double/decimal	3.14
String / ID	string	"alice" (quotes/backslashes/control chars escaped)
Boolean	bool	true / false
null	null	null
enum	new EnumValue("ADMIN")	ADMIN (unquoted)
variable	new Variable("$id", "ID!")	$id
list	new[] { … } / IList	[1, 2, 3]
input object	new Dictionary<string, object?>	{k:v, …} (alphabetized keys)
date	DateTime / DateTimeOffset	ISO-8601 quoted; verify against server's custom-scalar contract

CLR enums work but render as .ToString() — prefer EnumValue("EXACT_NAME") since GraphQL convention is SCREAMING_SNAKE_CASE and C# is PascalCase. Nest dicts/lists freely; variables can sit anywhere a value can.

In --var key=value (execute mode)

The tool JSON-parses each value; bare strings fall through.

--var first=10              # number
--var active=true           # bool
--var maybe=null            # null
--var name=alice            # bare string (parse failed)
--var name="Anne Ware"      # string with spaces
--var ids='[1,2,3]'         # list — single-quote JSON to protect from shell
--var filter='{"min":10}'   # input object — same

Variable("$x", "T") in a snippet → --var x=value on the CLI (no $).

Output rules

NGql renders with: 4-space indent, tight braces (users{ not users {), fields sorted alphabetically within a selection set, aliases appended after the un-aliased duplicate, strings double-quoted, enums unquoted, variables as $name:Type in the operation signature.

Snippet contract for ngql

The CLI evaluates a snippet as a Roslyn script: the final expression yields the builder, full stop.

• No var x = ...; ... (drop the assignment, end with the bare builder expression)
• No Console.WriteLine(...) (the tool prints .ToString() itself)
• No return (top-level scripts disallow it)
• No using lines for the auto-imported namespaces. ngql already imports System, System.Collections.Generic, System.Linq, NGql.Core, NGql.Core.Builders. Adding using NGql.Core.Builders; to a generated snippet is dead bytes — strip it. Only add using for namespaces you actually reference that aren't on that list (rare in practice — System.Text.Json if a value-formatter need it). The snippets in the worked examples below show the canonical bare shape.

Canonical shape:

QueryBuilder.CreateDefaultBuilder("Hello").AddField("world.name")

Feature gaps — refuse, don't fake

Construct	NGql
Inline fragments / union narrowing	✅ FieldBuilder.OnType("TypeName", b => …)
Named fragments (fragment X on T, ...X)	❌ — #20. Inline at each use site for now.
Directives (@include, @skip, custom)	❌
Subscriptions	❌

When the user needs a ❌ construct: stop before any C#, name the gap in one sentence, offer concrete paths (inline equivalent, partial + hand-splice, different field). Wait for the user's pick. Never generate broken code "for reference" — code that looks right but renders to invalid GraphQL is the worst failure mode.

When to ask before writing code

• Private/unknown API → ask for field names
• Mutations that change state (delete, transferFunds) → confirm name + input shape
• Ambiguous "drop X" → confirm which fields count
• Pasted operation has same-name fragments in multiple places → confirm merging vs separation vs aliasing

ngql runtime — when and how to invoke

dotnet-ngql compiles a snippet against NGql.Core and prints rendered GraphQL. Optionally executes against a live endpoint with --execute --endpoint URL.

Consent rules

• You may run ngql when the user explicitly asks ("send this", "run that", "execute it"). Other binaries (which, dotnet tool list, curl, cat, etc.) require ask-first consent — surface the intent, wait for "yes", then run. Never silently shell out for diagnostics.
• Render (no --execute) is side-effect-free. Ask once per session: "Want me to render this with ngql? (After yes, I'll auto-render later snippets — they're side-effect-free.)" Then auto-run subsequent renders. Revoke on user request.
• Execute (--execute) is always opt-in per call — network + possible side effects. Never auto-run.

Proactive offer after every snippet

One short sentence after the snippet block:

• "Want me to render this — echo '<snippet>' | ngql?" (or after first render-yes: just "Rendering…" and run)
• If the user gave an endpoint, also propose execute separately: "Or run against <URL> — echo '<snippet>' | ngql --execute --endpoint <URL>?"

Default to stdin (echo '…' | ngql) — one Bash call, one permission prompt, no file write. Use file path (ngql snippet.cs) only for long snippets (~30+ lines, intricate quoting). Mention briefly when you do: "Long enough to write to snippet.cs first."

Endpoint + mutation safety

Before the first execute call in a session, confirm:

1. The endpoint URL — read it aloud (localhost, staging, prod, third-party); pause for go-ahead unless localhost or a clear sandbox.
2. For mutations, that --allow-mutations is intentional. Frame the side-effect risk:

   Heads up — this is a mutation, it'll actually change data. If the endpoint is a sandbox / you have a backup, pass --allow-mutations. Otherwise drop --execute to dry-run.

Never pre-add --allow-mutations unless the user has explicitly confirmed.

Reading exit codes

Exit	Meaning	Next step
0	OK	If response body looks like HTML / echo dump / not a JSON data object — call it out. Don't claim success.
1	Snippet failed to compile	Offer to fix the snippet. Common causes: IDictionary<,> instead of Dictionary<,>, EnumValue(MyEnum.X) casing mismatch, an extra var x = …; … that left the file ending in a statement instead of a bare expression.
2	Server returned errors array	Interpret the GraphQL errors.
3	HTTP failure	Surface status code + stderr.
4	Mutation blocked	Offer --allow-mutations form (with safety re-check).
127	"command not found"	Either tool not installed OR ~/.dotnet/tools/ not on $PATH — check both. See install flow below.

Always report the actual exit code + stderr verbatim. One run, one report — no auto-retry loops. When you announce an action ("running which ngql"), perform exactly that — never substitute a different tool.

If the user says "no response" / "didn't work" / "nothing happened" without asking you to do anything: ask whether they actually ran the command first. Don't assume execution and pivot to diagnostics.

Install flow (when ngql is missing)

Ask two questions before suggesting a command — channel and scope.

Channel: default to whichever matches this Skill's own plugin name — /ngql-preview:ngql → preview, /ngql:ngql → stable. Frame as confirmation: "You're using the preview Skill, so I'd install the preview tool to match — sound right?"

Channel	Install	Note
stable	dotnet tool install -g dotnet-ngql	No stable on NuGet yet — install fails until it ships.
preview	dotnet tool install -g dotnet-ngql --prerelease	The --prerelease flag is required.

Scope: default-suggest local (per-project, version-pinned, reproducible):

• Local: dotnet new tool-manifest then dotnet tool install dotnet-ngql [--prerelease]. Invoke as dotnet ngql ....
• Global: dotnet tool install -g dotnet-ngql [--prerelease]. Invoke as ngql ....

Ask: "Local (recommended — pins the version) or global?" Wait for answer.

Version conflict (requested version is lower than existing version): ask user — keep their higher local OR dotnet tool uninstall [-g] dotnet-ngql && dotnet tool install [-g] dotnet-ngql [--prerelease] (uninstall + reinstall, only dotnet-ngql touched).

command not found after install: PATH issue. Global → export PATH="$PATH:$HOME/.dotnet/tools" (current shell) or persist in ~/.zshrc / ~/.bashrc. Local → invoke as dotnet ngql …, not bare ngql.

Worked examples

NL → builder, well-known API

"Get the top 10 repositories of GitHub user dolifer with name and stargazer count."

QueryBuilder.CreateDefaultBuilder("TopRepos")
    .AddField("user",
        new Dictionary<string, object?> { ["login"] = "dolifer" },
        b => b.AddField("repositories",
            new Dictionary<string, object?>
            {
                ["first"] = 10,
                ["orderBy"] = new Dictionary<string, object?>
                {
                    ["field"]     = new EnumValue("STARGAZERS"),
                    ["direction"] = new EnumValue("DESC"),
                },
            },
            new[] { "name", "stargazerCount" }))

Assumed schema (GitHub v4): user(login).repositories(first, orderBy) { name, stargazerCount }. Swap if your schema differs.

Mutation with variables

"CreateUser taking $name/$email, returning id and createdAt."

var nameVar  = new Variable("$name",  "String!");
var emailVar = new Variable("$email", "String!");

QueryBuilder.CreateMutationBuilder("CreateUser")
    .AddField("createUser",
        new Dictionary<string, object?> { ["name"] = nameVar, ["email"] = emailVar },
        new[] { "createdAt", "id" })

curl → builder (with auth pass-through)

When the user pastes a curl, extract three things and remember them for the rest of the session:

1. The GraphQL operation (curl body's query field) → the snippet.
2. The endpoint (curl URL) → the --endpoint for any later --execute offer.
3. Auth + custom headers (-H 'authorization: …', -H 'x-api-key: …', etc.) → -H flags ready to attach to --execute. Don't echo secret values back; refer to them as "the header you pasted."

Example input:

curl https://api.example.com/graphql \
  -H 'authorization: Bearer XXX' \
  -d '{"query":"query GetOrder($id: ID!) { order(id: $id) { id status total } }","variables":{"id":"42"}}'

Generated snippet:

var idVar = new Variable("$id", "ID!");

QueryBuilder.CreateDefaultBuilder("GetOrder")
    .AddField("order",
        new Dictionary<string, object?> { ["id"] = idVar },
        new[] { "id", "status", "total" })

When you offer to execute, propose with the captured pieces:

"Want me to run it against https://api.example.com/graphql with the authorization header you pasted — echo '<snippet>' | ngql --execute --endpoint https://api.example.com/graphql -H 'authorization: Bearer XXX' --var id=42?"

Standard execute consent rules apply (always ask; confirm endpoint isn't surprising; flag mutations).

Inline fragment (union narrowing)

"Search GitHub for top 10 starred repos, return name + stargazerCount + url."

QueryBuilder.CreateDefaultBuilder("TopRepos")
    .AddField("search",
        new Dictionary<string, object?>
        {
            ["query"] = "stars:>1",
            ["type"]  = new EnumValue("REPOSITORY"),
            ["first"] = 10,
        },
        b => b.AddField("nodes", n => n
            .OnType("Repository", r => r
                .AddField("name").AddField("stargazerCount").AddField("url"))))

The "Repository" is a schema type name, not user-defined. Multiple OnType calls on the same parent merge; fragments can nest (OnType("X", x => x.OnType("Y", …))).