diff --git a/7-Use-Cases.md b/7-Use-Cases.md
index 5877b05..3ff7d96 100644
--- a/7-Use-Cases.md
+++ b/7-Use-Cases.md
@@ -171,6 +171,56 @@ stays warm across follow-ups, and recyclable so it never outgrows its context wi
 
 Policy knobs in `bridged.yaml`: `idle_ttl`, `context_cap`, `max_workers_per_profile`.
 
+## Primary-side directive — *when* to delegate (a `CLAUDE.md` snippet)
+
+Mechanism 4 gives the **worker** a `CLAUDE.md` snippet so it knows how to answer. The **primary**
+needs the mirror image: a standing reminder to *reach for the bridge in the first place* instead of
+spending subscription tokens on work a cheaper worker could do. The trigger is an environment signal
+— the `bridged` MCP tools being connected (e.g. a `BRIDGED_MCP_URL` marker in the primary's env).
+When that property is set, this instance is a **bridge primary** and should delegate by default.
+
+The decision the directive encodes:
+
+```mermaid
+flowchart TD
+    T["a task arrives"] --> Q{"bridge available?<br/>(BRIDGED_MCP_URL set /<br/>bridged MCP connected)"}
+    Q -->|"no"| SELF["do it on the primary"]
+    Q -->|"yes"| J{"needs YOUR judgment,<br/>or bulk / mechanical / parallel?"}
+    J -->|"judgment / interactive"| SELF
+    J -->|"bulk / mechanical / parallel"| DEL["bridge_send → worker"]
+    classDef self fill:#2f855a,stroke:#22543d,color:#ffffff;
+    classDef del fill:#2b6cb0,stroke:#1a365d,color:#ffffff;
+    class SELF self
+    class DEL del
+```
+
+*Figure: an env property (bridge available) flips the default from "do it myself" to "delegate unless
+it needs my judgment."*
+
+Suggested snippet to drop into the primary's `CLAUDE.md`:
+
+```markdown
+## Delegating off-subscription work (claude-bridge)
+
+If the `bridged` MCP tools are connected (env marker `BRIDGED_MCP_URL` is set), you are a **bridge
+primary** on a metered subscription. Default to pushing work that does not need your own judgment to
+a cheaper worker instead of spending subscription tokens on it:
+
+- **Delegate** bulk, mechanical, or parallelizable work — test writing, log triage, wide-area or
+  per-file reviews, codegen/refactors behind a clear spec — with
+  `bridge_send(to: <role@profile>, kind: <verb.noun>, body: {...})`. Fan several out and reduce.
+- **Keep on the primary** the conversation with the user, final judgment, merge/commit decisions,
+  and anything that needs your on-subscription model's reasoning.
+- **Never set `ANTHROPIC_BASE_URL` yourself.** Routing to an off-subscription model is the worker's
+  job (its ccs profile carries it); you stay env-clean — that boundary is the whole point of the bridge.
+
+Rule of thumb: if you could hand the task to a junior with a written brief, `bridge_send` it.
+```
+
+This is a *suggestion*, not wiring: `bridged` never edits the primary's `CLAUDE.md` (that would cross
+the subscription boundary in the wrong direction). The operator pastes it; the env property is what
+makes the reminder fire only in sessions where a bridge actually exists.
+
 ## More use cases (catalogue)
 
 Same machinery, different `kind`/lifecycle: