diff --git a/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/agent.py b/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/agent.py
index 88baac0d88..3e0f4b8459 100644
--- a/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/agent.py
+++ b/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/agent.py
@@ -413,6 +413,11 @@ def system_prompt(self) -> str:
      and re-check before concluding.
    - If you confirmed that the reported broken behaviour reproduces in both browsers,
    set `failure_reason` to `not_firefox_specific`.
+   - NOTE: Reports about the site steering users away from Firefox (a
+     "use Chrome" recommendation, an unsupported-browser warning, or a
+     user-agent-based block) are considered valid web compatibility issues even
+     if the same message displayed in Chrome. Seeing that message in Firefox
+     is the reproduction: set `reproduced` to true.
 4. If the issue reproduces, write and run a Puppeteer script that drives the real
    reported site in both browsers and demonstrates the difference: follow the spec in
    `{repro_reference}`, write your script to exactly `{self.script_path}`
diff --git a/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/prompts/system.md b/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/prompts/system.md
index eb7c65eb01..ec4e5c1ad9 100644
--- a/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/prompts/system.md
+++ b/agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/prompts/system.md
@@ -27,6 +27,20 @@ some or all of a website, or which would cause the website to look or
 behave noticeably different or worse in Firefox compared to other
 browsers.
 
+A site that steers users away from Firefox is a webcompat issue even if
+the page otherwise renders and works identically in every browser. This
+includes:
+
+- Telling users to switch to, or that the site is best viewed in, another
+  browser (e.g. "it is recommended to use Chrome").
+- Warning that Firefox is unsupported, or that some feature will not work
+  in Firefox.
+- Blocking Firefox outright, or serving it a degraded/legacy experience,
+  based on user-agent sniffing.
+
+Treat these as webcompat - the recommendation or block is itself 
+the issue to report.
+
 Issues with the browser UI are not webcompat issues unless they
 specifically affect the ability to access content on a specific site.