diff --git a/packages/core/src/plugin/skill/customize-opencode.md b/packages/core/src/plugin/skill/customize-opencode.md
index 5b51f8f2ab7..99b112d9a55 100644
--- a/packages/core/src/plugin/skill/customize-opencode.md
+++ b/packages/core/src/plugin/skill/customize-opencode.md
@@ -303,7 +303,7 @@ Special object-shaped (not callbacks): `tool: { my_tool: { ... } }`,
       "type": "remote",
       "url": "https://...",
       "enabled": true,
-      "headers": { "Authorization": "Bearer ${GITHUB_TOKEN}" }
+      "headers": { "Authorization": "Bearer {env:GITHUB_TOKEN}" }
     },
     "old-server": { "enabled": false }
   }
@@ -311,7 +311,9 @@ Special object-shaped (not callbacks): `tool: { my_tool: { ... } }`,
 ```
 
 `command` is an array of strings. `type` is required. Use `enabled: false` to
-disable a server inherited from a parent config.
+disable a server inherited from a parent config. String values such as header
+tokens support `{env:VAR}` interpolation (and `{file:path}`); the shell-style
+`${VAR}` is not substituted.
 
 ## Permissions
 
diff --git a/packages/opencode/src/tool/task.ts b/packages/opencode/src/tool/task.ts
index 1ac9d4d9ad8..5ca1666add7 100644
--- a/packages/opencode/src/tool/task.ts
+++ b/packages/opencode/src/tool/task.ts
@@ -30,13 +30,13 @@ const BACKGROUND_DESCRIPTION = [
 ].join(" ")
 const BACKGROUND_STARTED = [
   "The task is working in the background. You will be notified automatically when it finishes.",
-  "Do not poll for progress, ask the task for status, or duplicate this task's work — avoid working with the same files or topics it is using.",
+  "DO NOT sleep, poll for progress, ask the task for status, or duplicate this task's work — avoid working with the same files or topics it is using.",
   "Work on non-overlapping tasks, or briefly tell the user what you launched and end your response.",
 ].join("\n")
 const BACKGROUND_UPDATED = [
   "Additional context sent to the running background task.",
   "The task is still working in the background. You will be notified automatically when it finishes.",
-  "Do not poll for progress, ask the task for status, or duplicate this task's work — avoid working with the same files or topics it is using.",
+  "DO NOT sleep, poll for progress, ask the task for status, or duplicate this task's work — avoid working with the same files or topics it is using.",
   "Work on non-overlapping tasks, or briefly tell the user what you sent and end your response.",
 ].join("\n")
 
@@ -56,7 +56,8 @@ const BaseParameters = Schema.Struct(BaseParameterFields)
 export const Parameters = Schema.Struct({
   ...BaseParameterFields,
   background: Schema.optional(Schema.Boolean).annotate({
-    description: "Run the agent in the background. You will be notified when it completes.",
+    description:
+      "Run the agent in the background. You will be notified when it completes. DO NOT sleep, poll, or proactively check on its progress",
   }),
 })
 
diff --git a/packages/opencode/test/tool/__snapshots__/parameters.test.ts.snap b/packages/opencode/test/tool/__snapshots__/parameters.test.ts.snap
index 0bf2357eff8..b187b191c1f 100644
--- a/packages/opencode/test/tool/__snapshots__/parameters.test.ts.snap
+++ b/packages/opencode/test/tool/__snapshots__/parameters.test.ts.snap
@@ -320,7 +320,7 @@ exports[`tool parameters JSON Schema (wire shape) task 1`] = `
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "properties": {
     "background": {
-      "description": "Run the agent in the background. You will be notified when it completes.",
+      "description": "Run the agent in the background. You will be notified when it completes. DO NOT sleep, poll, or proactively check on its progress",
       "type": "boolean",
     },
     "command": {