docs: improve docs and agent discovery metadata (#5243)

## Summary

- Fix TypeScript view examples to use `ctx.sender` as a property,
matching the server SDK `ViewCtx` API.
- Update the architecture overview TypeScript view snippet to use
`players.rowType` and `undefined` for optional view returns.
- Clarify shared `ViewContext` prose so it does not imply every language
uses a callable `ctx.sender()` API.
- Improve docs agent-readiness metadata:
- publish `/docs/robots.txt` with a docs sitemap directive and
Content-Signal policy
- add Markdown alternate links for the existing `/docs/llms.txt` and
`/docs/llms-full.txt` outputs
- generate `/.well-known/agent-skills`-style discovery metadata under
`/docs/.well-known/agent-skills/` from the repo's existing `skills/`
source files during docs builds

## Validation

- `pnpm --dir docs build`
- `pnpm --dir docs typecheck`
- Verified the docs build emits `robots.txt` and
`.well-known/agent-skills/index.json`.
- Verified generated Agent Skills SHA-256 digests match the emitted
`SKILL.md` artifacts.

## Notes

The Cloudflare agent-readiness scan for `spacetimedb.com` still depends
on the root/marketing host exposing root-level files such as
`/robots.txt`, `/sitemap.xml`, and
`/.well-known/agent-skills/index.json`. This PR makes the docs origin
produce the corresponding docs-scoped artifacts at `/docs/...`; the root
host can route or mirror these if we want the exact `spacetimedb.com`
scan to pick them up.

---------

Co-authored-by: clockwork-labs-bot <clockwork-labs-bot@users.noreply.github.com>
Co-authored-by: rain <rain@rain.local>
Co-authored-by: Tyler Cloutier <cloutiertyler@users.noreply.github.com>

Author: 3 people

docs/.gitignore

@@ -7,6 +7,7 @@
 # Generated files
 .docusaurus
 .cache-loader
+static/.well-known/agent-skills/
 
 # Misc
 .DS_Store

docs/docs/00100-intro/00100-getting-started/00400-key-architecture.md

@@ -495,10 +495,10 @@ A view can be written in a TypeScript module like so:
 ```typescript
 export const my_player = spacetimedb.view(
   { name: 'my_player', public: true },
-  t.option(players.row()),
+  t.option(players.rowType),
   (ctx) => {
     const row = ctx.db.players.identity.find(ctx.sender);
-    return row ?? null;
+    return row ?? undefined;
   }
 );
 ```

docs/docs/00200-core-concepts/00200-functions/00300-reducers/00300-reducers.md

@@ -30,14 +30,14 @@ export const create_user = spacetimedb.reducer({ name: t.string(), email: t.stri
 
   // Modify tables
   ctx.db.user.insert({
-    id: 0,  // auto-increment will assign
+    id: 0n,  // auto-increment will assign
     name,
     email
   });
 });
 ```
 
-The first argument is the reducer name, the second defines argument types, and the third is the handler function taking `(ctx, args)`.
+The exported const name becomes the reducer name. Pass an argument type object followed by a handler function taking `(ctx, args)`. For reducers with no arguments, pass only the handler function.
 
 </TabItem>
 <TabItem value="csharp" label="C#">
@@ -127,8 +127,8 @@ SPACETIMEDB_REDUCER(create_user, ReducerContext ctx, std::string name, std::stri
     }
 
     // Modify tables
-    User user{0, name, email};  // 0 for id - auto-increment will assign
-    ctx.db[user].insert(user);
+    User new_user{0, name, email};  // 0 for id - auto-increment will assign
+    ctx.db[user].insert(new_user);
 
     return Ok();
 }
@@ -160,7 +160,7 @@ Reducers have full read-write access to all tables (both public and private) thr
 
 ```typescript
 ctx.db.user.insert({
-  id: 0,  // auto-increment will assign
+  id: 0n,  // auto-increment will assign
   name: 'Alice',
   email: 'alice@example.com'
 });

docs/docs/00200-core-concepts/00200-functions/00300-reducers/00400-reducer-context.md

@@ -274,15 +274,15 @@ Never use external random number generators (like `Random` in C# without using t
 
 ## Module Identity
 
-The context provides access to the module's own identity, which is useful for distinguishing between user-initiated and system-initiated reducer calls.
+The context provides access to the module's own identity, which is useful when a reducer needs to refer to the database itself.
 
-This is particularly important for [scheduled reducers](./00300-reducers.md) that should only be invoked by the system, not by external clients.
+Scheduled reducers and procedures are private by default in SpacetimeDB 2.x, so you do not need to compare the sender against the module identity to prevent ordinary clients from calling them directly. If you need both a scheduled function and a client-callable entry point, keep the scheduled function private and define a separate public reducer that wraps the shared logic.
 
 <Tabs groupId="server-language" queryString>
 <TabItem value="typescript" label="TypeScript">
 
 ```typescript
-import { schema, table, t, SenderError } from 'spacetimedb/server';
+import { schema, table, t } from 'spacetimedb/server';
 
 const scheduledTask = table(
   { name: 'scheduled_task', scheduled: (): any => send_reminder },
@@ -296,12 +296,7 @@ const scheduledTask = table(
 const spacetimedb = schema({ scheduledTask });
 export default spacetimedb;
 
-export const send_reminder = spacetimedb.reducer({ arg: scheduledTask.rowType }, (ctx, { arg }) => {
-  // Only allow the scheduler (module identity) to call this
-  if (ctx.sender != ctx.identity) {
-    throw new SenderError('This reducer can only be called by the scheduler');
-  }
-  
+export const send_reminder = spacetimedb.reducer({ arg: scheduledTask.rowType }, (_ctx, { arg }) => {
   console.log(`Reminder: ${arg.message}`);
 });
 ```
@@ -325,14 +320,8 @@ public static partial class Module
     }
 
     [SpacetimeDB.Reducer]
-    public static void SendReminder(ReducerContext ctx, ScheduledTask task)
+    public static void SendReminder(ReducerContext _ctx, ScheduledTask task)
     {
-        // Only allow the scheduler (module identity) to call this
-        if (ctx.Sender != ctx.Identity)
-        {
-            throw new Exception("This reducer can only be called by the scheduler");
-        }
-        
         Log.Info($"Reminder: {task.message}");
     }
 }
@@ -354,12 +343,7 @@ pub struct ScheduledTask {
 }
 
 #[reducer]
-fn send_reminder(ctx: &ReducerContext, task: ScheduledTask) {
-    // Only allow the scheduler (module identity) to call this
-    if ctx.sender() != ctx.identity() {
-        panic!("This reducer can only be called by the scheduler");
-    }
-    
+fn send_reminder(_ctx: &ReducerContext, task: ScheduledTask) {
     spacetimedb::log::info!("Reminder: {}", task.message);
 }
 ```
@@ -383,12 +367,7 @@ FIELD_PrimaryKeyAutoInc(scheduled_task, task_id);
 // Register the table for scheduling (column 1 = scheduled_at field, 0-based index)
 SPACETIMEDB_SCHEDULE(scheduled_task, 1, send_reminder);
 
-SPACETIMEDB_REDUCER(send_reminder, ReducerContext ctx, ScheduledTask task) {
-    // Only allow the scheduler (module identity) to call this
-    if (ctx.sender() != ctx.identity()) {
-        return Err("This reducer can only be called by the scheduler");
-    }
-    
+SPACETIMEDB_REDUCER(send_reminder, ReducerContext _ctx, ScheduledTask task) {
     LOG_INFO("Reminder: " + task.message);
     return Ok();
 }

docs/docs/00200-core-concepts/00200-functions/00300-reducers/00500-lifecycle.md

@@ -22,7 +22,7 @@ export const init = spacetimedb.init((ctx) => {
   console.log('Database initializing...');
 
   // Set up default data
-  if (ctx.db.settings.count === 0) {
+  if (ctx.db.settings.count() === 0n) {
     ctx.db.settings.insert({
       key: 'welcome_message',
       value: 'Hello, SpacetimeDB!'
@@ -133,7 +133,7 @@ export const init = spacetimedb.init((ctx) => {
 <TabItem value="csharp" label="C#">
 
 ```csharp
-[SpacetimeDB.Table(Name = "Config")]
+[SpacetimeDB.Table(Accessor = "Config")]
 public partial struct Config
 {
     [SpacetimeDB.PrimaryKey]

docs/docs/00200-core-concepts/00200-functions/00300-reducers/00600-error-handling.md

@@ -25,9 +25,9 @@ Throw a `SenderError`:
 import { SenderError } from 'spacetimedb/server';
 
 export const transfer_credits = spacetimedb.reducer(
-  { to_user: t.u64(), amount: t.u32() },
+  { to_user: t.identity(), amount: t.u32() },
   (ctx, { to_user, amount }) => {
-    const fromUser = ctx.db.users.id.find(ctx.sender);
+    const fromUser = ctx.db.users.identity.find(ctx.sender);
     if (!fromUser) {
       throw new SenderError('User not found');
     }
@@ -60,9 +60,9 @@ Throw an exception:
 
 ```csharp
 [SpacetimeDB.Reducer]
-public static void TransferCredits(ReducerContext ctx, ulong toUser, uint amount)
+public static void TransferCredits(ReducerContext ctx, Identity toUser, uint amount)
 {
-    var fromUser = ctx.Db.User.Id.Find(ctx.Sender);
+    var fromUser = ctx.Db.User.Identity.Find(ctx.Sender);
     if (fromUser == null)
     {
         throw new InvalidOperationException("User not found");
@@ -86,13 +86,13 @@ Return an error:
 #[reducer]
 pub fn transfer_credits(
     ctx: &ReducerContext,
-    to_user: u64,
+    to_user: Identity,
     amount: u32
 ) -> Result<(), String> {
-    let from_balance = ctx.db.users().id().find(ctx.sender.identity)
-        .ok_or("User not found");
+    let from_user = ctx.db.users().identity().find(ctx.sender())
+        .ok_or("User not found")?;
 
-    if from_balance.credits < amount {
+    if from_user.credits < amount {
         return Err("Insufficient credits".to_string());
     }
 

docs/docs/00200-core-concepts/00200-functions/00500-views.md

@@ -57,7 +57,7 @@ export const my_player = spacetimedb.view(
     { name: 'my_player', public: true },
     t.option(players.rowType),
     (ctx) => {
-        const row = ctx.db.players.identity.find(ctx.sender());
+        const row = ctx.db.players.identity.find(ctx.sender);
         return row ?? undefined;
     }
 );
@@ -245,7 +245,7 @@ struct Player {
 };
 SPACETIMEDB_STRUCT(Player, id, identity, name)
 SPACETIMEDB_TABLE(Player, player, Public)
-FIELD_PrimaryKeyAuto(player, id)
+FIELD_PrimaryKeyAutoInc(player, id)
 FIELD_Unique(player, identity)
 
 struct PlayerLevel {
@@ -294,7 +294,7 @@ Views can return `std::optional<T>` for at-most-one row, `std::vector<T>` for mu
 
 Views use one of two context types:
 
-- **`ViewContext`**: Provides access to the caller's `Identity` through `ctx.sender()`. Use this when the view depends on who is querying it.
+- **`ViewContext`**: Provides access to the caller's `Identity` through the context's sender field or method. Use this when the view depends on who is querying it.
 - **`AnonymousViewContext`**: Does not provide caller information. Use this when the view produces the same results regardless of who queries it.
 
 Both contexts provide read-only access to tables and indexes through `ctx.db`.
@@ -305,7 +305,7 @@ The choice between `ViewContext` and `AnonymousViewContext` has significant perf
 
 **Anonymous views can be shared across all subscribers.** When a view uses `AnonymousViewContext`, SpacetimeDB knows the result is the same for every client. The database can materialize the view once and serve that same result to all subscribers. When the underlying data changes, it recomputes the view once and broadcasts the update to everyone.
 
-**Per-user views require separate computation for each subscriber.** When a view uses `ViewContext` and invokes `ctx.sender()`, each client potentially sees different data. SpacetimeDB must compute and track the view separately for each subscriber. With 1,000 connected users, that's 1,000 separate view computations and 1,000 separate sets of change tracking.
+**Per-user views require separate computation for each subscriber.** When a view uses `ViewContext` and reads the caller's sender identity, each client potentially sees different data. SpacetimeDB must compute and track the view separately for each subscriber. With 1,000 connected users, that's 1,000 separate view computations and 1,000 separate sets of change tracking.
 
 **Prefer `AnonymousViewContext` when possible.** Design your views to be caller-independent when the use case allows. For example:
 

docs/docs/00200-core-concepts/00300-tables.md

@@ -320,7 +320,7 @@ Use idiomatic naming conventions for each language:
 | Language | Convention | Example Table | Example Accessor |
 |----------|------------|---------------|------------------|
 | **TypeScript** | snake_case | `'player_score'` | `ctx.db.playerScore` |
-| **C#** | PascalCase | `Name = "PlayerScore"` | `ctx.Db.PlayerScore` |
+| **C#** | PascalCase | `Accessor = "PlayerScore"` | `ctx.Db.PlayerScore` |
 | **Rust** | lower_snake_case | `name = player_score` | `ctx.db.player_score()` |
 | **C++** | lower_snake_case | `player_score` | `ctx.db[player_score]` |
 

docs/docs/00200-core-concepts/00300-tables/00210-file-storage.md

@@ -211,7 +211,7 @@ export const register_document = spacetimedb.reducer({
   storageUrl: t.string(),
 }, (ctx, { filename, mimeType, sizeBytes, storageUrl }) => {
   ctx.db.document.insert({
-    id: 0,  // auto-increment
+    id: 0n,  // auto-increment
     ownerId: ctx.sender,
     filename,
     mimeType,

docs/docs/00200-core-concepts/00300-tables/00400-access-permissions.md

@@ -136,9 +136,9 @@ Reducers receive a `ReducerContext` which provides full read-write access to all
 <TabItem value="typescript" label="TypeScript">
 
 ```typescript
-export const example = spacetimedb.reducer({}, (ctx) => {
+export const example = spacetimedb.reducer((ctx) => {
   // Insert
-  ctx.db.user.insert({ id: 0, name: 'Alice', email: 'alice@example.com' });
+  ctx.db.user.insert({ id: 0n, name: 'Alice', email: 'alice@example.com' });
 
   // Read: iterate all rows
   for (const user of ctx.db.user.iter()) {