Fill gaps from assistant conversations: Salesforce namespace error, write quota

src/provider-guides/salesforce.mdx

@@ -1,5 +1,6 @@
 ---
 title: "Salesforce"
+description: "Set up Salesforce for Ampersand: create an External Client App, register and link a namespace, and enable read, write, and subscribe actions."
 ---
 
 The Salesforce connector supports:
@@ -181,7 +182,7 @@ Please note that namespaces cannot be created in the Dev Hub Org you just enable
 * Log in to the Dev Hub Org from Step 1.
 * Open **App Launcher** (9 dots at the top left), and search for **Namespace Registries**.
 * Click **Link Namespace** on the top right.
-* When prompted to authenticate, log into the Namespace Org from Step 2. If you are having trouble with this step, try again in an incognito window.
+* When prompted to authenticate, log into the Namespace Org from Step 2. If you are having trouble with this step, such as an `invalid_request: missing required code challenge` error, try again in an incognito window. See [the troubleshooting guide](/troubleshooting-guides/salesforce#namespace-linking-missing-required-code-challenge-error) for details.
 * After linking, select **All Namespace Registries** filter to view the namespace.
 
 ![Link namespace](/images/provider-guides/salesforce/link-namespace.png)

src/troubleshooting-guides/salesforce.mdx

@@ -1,6 +1,6 @@
 ---
 title: "Salesforce"
-description: "Diagnose and resolve common errors when running Salesforce integrations."
+description: "Diagnose and resolve common Salesforce integration errors, including No such column read and write failures and namespace linking OAuth errors."
 ---
 
 ## Read Action: `No such column` error
@@ -64,3 +64,19 @@ Remove the field from your write payload for this customer — for example, by c
 ### Connected user lacks field-level visibility
 
 If the field exists in the org but isn't visible to the connected user's profile, Salesforce returns the same `No such column` error. Follow the steps in [Resolve a field-level visibility issue](#resolve-a-field-level-visibility-issue).
+
+## Namespace linking: `missing required code challenge` error
+
+While [linking your namespace to the Dev Hub Org](/provider-guides/salesforce#3-link-namespace-to-dev-hub-org), Salesforce redirects with an error similar to:
+
+```text
+error=invalid_request&error_description=missing%20required%20code%20challenge
+```
+
+This error comes from Salesforce's login flow, not from Ampersand. It typically happens when your browser reuses an existing Salesforce session during the **Link Namespace** authentication step.
+
+To resolve it:
+
+1. Open an incognito or private browsing window.
+2. Log in to the Dev Hub Org and retry the **Link Namespace** flow, logging into the Namespace Org when prompted.
+3. If the error persists, log out of all Salesforce orgs, clear cookies for `salesforce.com` and `force.com`, and try again.

src/write-actions.mdx

@@ -1,8 +1,9 @@
 ---
 title: "Write actions"
+description: "Define write actions in amp.yaml to create and update records in your customer's SaaS, with batching, async mode, and automatic retries."
 ---
 
-A write action writes data to your customer's SaaS whenever you make an API request to us. This page focuses on writing data to existing fields. If you are looking to create new custom fields prior to writing data, please see [Create or update custom fields](/manage-customer-schemas#create-or-update-custom-fields).
+A write action writes data to your customer's SaaS whenever you make an API request to us. Writes are made through your customer's connection, so they consume API quota in your customer's SaaS instance, not Ampersand's. This page focuses on writing data to existing fields. If you are looking to create new custom fields prior to writing data, please see [Create or update custom fields](/manage-customer-schemas#create-or-update-custom-fields).
 
 ## Defining writes