diff --git a/README.md b/README.md
index f007b93..564d22e 100644
--- a/README.md
+++ b/README.md
@@ -144,7 +144,7 @@ A new tool is available:
 
 ## Environment variables
 
-See env.example for a full list.
+See env.example for a ready-to-use template.
 
 Core:
 
@@ -164,7 +164,7 @@ Single-account IMAP (only if not using ACCOUNTS_JSON/ACCOUNTS_CONFIG_PATH):
 - IMAP_USERNAME
 - IMAP_PASSWORD
 
-Single-account SMTP:
+Single-account SMTP (only if not using ACCOUNTS_JSON/ACCOUNTS_CONFIG_PATH):
 
 - SMTP_HOST
 - SMTP_PORT
@@ -174,12 +174,37 @@ Single-account SMTP:
 - SMTP_PASSWORD
 - SMTP_FROM
 
-Optional email:
+Multi-account configuration:
+
+- ACCOUNTS_JSON:
+  - Inline JSON array of accounts (alternative to a mounted file).
+- ACCOUNTS_CONFIG_PATH:
+  - Path inside the container to a JSON file with account definitions.
+- DEFAULT_ACCOUNT:
+  - Default account ID to use when tools are called without specifying "account".
+  - If blank:
+    - If only one account exists, it is default.
+    - Otherwise, an account with id "default" is preferred, or the first one is used.
+
+Time and timezone:
+
+- TIMEZONE:
+  - IANA timezone used by get_current_time (e.g. "America/New_York", "Europe/London", "UTC").
+  - Default: "UTC".
+  - Example:
+      -e TIMEZONE="America/New_York"
+
+Optional email defaults:
 
 - DEFAULT_CC: Comma-separated CC addresses.
 - DEFAULT_BCC: Comma-separated BCC addresses.
-- BUSINESS_DESCRIPTION: Context for the LLM (e.g., firm description).
-- PERSONNEL_JSON: JSON array of personnel/chain-of-command:
+
+Business and triage context:
+
+- BUSINESS_DESCRIPTION:
+  - Context for the LLM (e.g., firm description).
+- PERSONNEL_JSON:
+  - JSON array of personnel/chain-of-command.
   - Example:
     [
       {
@@ -195,28 +220,26 @@ Optional email:
         "escalates_to": "Jane Doe"
       }
     ]
-- SCHEDULED_SEND_INTERVAL: Seconds between checks for scheduled emails (default: 10).
 
-Time and timezone:
+Scheduling:
 
-- TIMEZONE:
-  - IANA timezone used by get_current_time (e.g. "America/New_York", "Europe/London", "UTC").
-  - Default: "UTC".
-  - Example:
-      -e TIMEZONE="America/New_York"
+- SCHEDULED_SEND_INTERVAL:
+  - Seconds between checks for scheduled emails (default: 10).
 
-HTML, signature, and LLM identity:
+HTML signature and LLM identity:
 
-- Emails (send_email, reply_to_message, forward_message, schedule_send) default to HTML (html=true) unless explicitly set to false.
-- EMAIL_HTML_SIGNATURE: Optional HTML signature appended to HTML emails.
-  - Inline HTML example:
+- EMAIL_HTML_SIGNATURE:
+  - Optional HTML signature appended to HTML emails.
+  - Can be:
+    - Inline HTML string, or
+    - A file path inside the container (e.g. /etc/mcp-email/signature.html).
+  - Inline example:
       -e EMAIL_HTML_SIGNATURE='<div style="font-size:12px;">Best regards,<br>Jane Doe<br>Associate</div>'
   - Template file example:
-      - Mount the file:
+      - Mount:
           -v /path/to/signature.html:/etc/mcp-email/signature.html:ro
-      - Set env:
+      - Set:
           -e EMAIL_HTML_SIGNATURE='/etc/mcp-email/signature.html'
-    If the value is an existing file path, its contents are used as the signature.
 
 - Signature template variables:
   - The signature can include placeholders:
@@ -257,6 +280,25 @@ HTML, signature, and LLM identity:
       }
   - The LLM must provide accurate identity details; do not leave these fields blank or generic.
 
+External summary model (for summarize_email):
+
+- EXTERNAL_SUMMARY_MODEL_ENDPOINT:
+  - OpenAI-compatible /v1/chat/completions endpoint.
+  - Example: http://localhost:8080/v1
+- EXTERNAL_SUMMARY_MODEL_API_KEY:
+  - API key for the external model.
+- EXTERNAL_SUMMARY_MODEL_NAME:
+  - Model name (default: gpt-4o-mini).
+- EXTERNAL_SUMMARY_MAX_TOKENS:
+  - Max tokens for each summary (default: 400).
+
+CalDAV / CardDAV (e.g., Nextcloud) - if used by integrations:
+
+- DAV_BASE_URL
+- DAV_USERNAME
+- DAV_PASSWORD
+- DAV_VERIFY_TLS
+
 ## MCP tools
 
 All tools are exposed via MCP (Streamable HTTP) at POST /mcp.