diff --git a/src/commands/completions.ts b/src/commands/completions.ts
index 54a144f..ad35d72 100644
--- a/src/commands/completions.ts
+++ b/src/commands/completions.ts
@@ -1,4 +1,5 @@
 import type { Command, Option } from "commander"
+import { DEFAULTS } from "../config.ts"
 
 /** Generate fish completion lines from the Commander program tree. */
 export function generateFishCompletions(program: Command): string[] {
@@ -51,6 +52,13 @@ export function generateFishCompletions(program: Command): string[] {
     lines.push(`complete -c sandlot -n "__fish_seen_subcommand_from ${branchCommands.join(" ")}" -xa "(__sandlot_sessions)"`)
   }
 
+  // Config key completions
+  const configKeys = Object.keys(DEFAULTS)
+  if (configKeys.length > 0) {
+    lines.push("")
+    lines.push(`complete -c sandlot -n "__fish_seen_subcommand_from config" -xa "${configKeys.join(" ")}"`)
+  }
+
   lines.push("")
   return lines
 }