diff --git a/claude-plugins/plugins/base/skills/claude-subagents/SKILL.md b/claude-plugins/plugins/base/skills/claude-subagents/SKILL.md
index 222cc088..d3d667f2 100644
--- a/claude-plugins/plugins/base/skills/claude-subagents/SKILL.md
+++ b/claude-plugins/plugins/base/skills/claude-subagents/SKILL.md
@@ -62,10 +62,11 @@ well-scoped batch (the shape this skill is for), reach for it liberally
 rather than defaulting to a bigger model "to be safe." On a small context
 Haiku costs next to nothing up to `high` effort, so there's no cost reason
 to cap its effort at `medium` by reflex. Effort is a real lever on Haiku
-though: at `max` it behaves like a slightly weaker Sonnet at about Sonnet's
-cost, so `max` on Haiku buys nothing over picking Sonnet. Stay at `high` or
-below, and move to a stronger model when the batch needs more judgement
-(see Pitfalls below).
+though: at `max` it behaves like a slightly weaker Sonnet at about the cost
+of Sonnet on `low`, so `max` on Haiku buys nothing over Sonnet on `low`.
+Stay at `high` or below, and move to a stronger model when the batch needs
+more judgement (see Pitfalls below). When you do pick Sonnet, pass `low`
+yourself: its default effort is `high`, a big price bump.
 
 This isn't "always pick the smallest model regardless of task" — a batch
 that actually needs judgement calls still wants a stronger model (see
diff --git a/hive-subagent-mcp/src/mcp.rs b/hive-subagent-mcp/src/mcp.rs
index 09e74539..76f528fa 100644
--- a/hive-subagent-mcp/src/mcp.rs
+++ b/hive-subagent-mcp/src/mcp.rs
@@ -60,7 +60,7 @@ struct StartArgs {
     /// Anthropic's own guidance on choosing between levels. On Haiku with a
     /// small context, effort up to `high` costs next to nothing, so there's
     /// no cost reason to cap it at `medium`; at `max` it costs about what
-    /// Sonnet does.
+    /// Sonnet does on `low` (Sonnet's own default is `high`, a big price bump).
     #[serde(default)]
     effort: Option<String>,
     /// Path to a file holding the subagent's actual task instructions. A