[eric] prompt: reading the web starts with WebSearch/WebFetch and only escalates to the browser when they come back thin

backend/apps/settings/models.py

@@ -33,8 +33,10 @@ DEFAULT_SYSTEM_PROMPT = (
     "4. **Unsure which server.** `MCPList` for a cheap survey, or "
     '`MCPSearch("<what you need>")` to rank servers by relevance. Do this before '
     "MCPActivate, never via ToolSearch.\n"
-    "5. **No tool fits.** WebSearch / WebFetch for information. BrowserAgent only for "
-    "visual interaction, form filling, or sites with no API path.\n\n"
+    "5. **Reading the web.** WebSearch / WebFetch first, always: they are far faster than "
+    "driving a browser and they cover ordinary pages. Escalate to BrowserAgent only once "
+    "they have actually come back thin or blocked (login wall, paywall, JS-only page), or "
+    "when the task needs visual interaction or form filling.\n\n"
     "### Choosing among similar names\n"
     "A matching name is a hypothesis, not an answer. Before calling, read the description "
     "and the required parameters, and confirm three things: it performs the action you "

backend/apps/settings/store.py

@@ -50,8 +50,19 @@ P_LEGACY_DEFAULT_SYSTEM_PROMPT = (
     "If you genuinely need clarification on something ambiguous, use the "
     "AskUserQuestion tool. Never ask questions inline in plain text.\n"
 )
+# The 820cf578-era revision, which differs from the current default only in ladder step 5 (it framed
+# the web tools as "No tool fits" so agents reached for the browser first). Derived, not duplicated.
+P_LEGACY_LADDER_V1 = DEFAULT_SYSTEM_PROMPT.replace(
+    "5. **Reading the web.** WebSearch / WebFetch first, always: they are far faster than "
+    "driving a browser and they cover ordinary pages. Escalate to BrowserAgent only once "
+    "they have actually come back thin or blocked (login wall, paywall, JS-only page), or "
+    "when the task needs visual interaction or form filling.\n\n",
+    "5. **No tool fits.** WebSearch / WebFetch for information. BrowserAgent only for "
+    "visual interaction, form filling, or sites with no API path.\n\n",
+)
 P_LEGACY_DEFAULT_SYSTEM_PROMPTS = (
     P_LEGACY_DEFAULT_SYSTEM_PROMPT,
+    P_LEGACY_LADDER_V1,
     P_LEGACY_DEFAULT_SYSTEM_PROMPT.replace(
         "1. Connected MCP tools; fastest and most reliable. To reach an integration you "
         "don't already see, use MCPSearch then MCPActivate; never ToolSearch for it.\n",

backend/tests/test_default_prompt_migration.py

@@ -0,0 +1,52 @@
+"""Shipping a new default system prompt has to carry the old one with it.
+
+The default persists into settings.json, so bumping the constant alone leaves every existing install
+on the old text forever: they never see the change, and "Reset to default" compares against something
+that no longer exists. Each legacy revision is derived from the current default with a `replace`, and
+a `replace` whose anchor has drifted silently returns the string unchanged, which turns the whole
+migration into a no-op that nothing would notice. These pin both halves.
+"""
+
+from backend.apps.settings.models import DEFAULT_SYSTEM_PROMPT
+from backend.apps.settings.store import (
+    P_LEGACY_DEFAULT_SYSTEM_PROMPT,
+    P_LEGACY_DEFAULT_SYSTEM_PROMPTS,
+    P_LEGACY_LADDER_V1,
+)
+
+
+def test_every_legacy_revision_actually_differs_from_the_current_default():
+    """A derived revision equal to the default means its anchor text drifted and the replace did
+    nothing, so users on that revision would never be migrated off it."""
+    for i, legacy in enumerate(P_LEGACY_DEFAULT_SYSTEM_PROMPTS):
+        assert legacy != DEFAULT_SYSTEM_PROMPT, (
+            f"legacy revision {i} is byte-identical to the current default, so its derivation "
+            "silently no-opped, most likely because the anchor string it replaces was edited"
+        )
+
+
+def test_the_shipped_revisions_are_all_tracked():
+    assert P_LEGACY_DEFAULT_SYSTEM_PROMPT in P_LEGACY_DEFAULT_SYSTEM_PROMPTS
+    assert P_LEGACY_LADDER_V1 in P_LEGACY_DEFAULT_SYSTEM_PROMPTS
+    assert len(set(P_LEGACY_DEFAULT_SYSTEM_PROMPTS)) == len(P_LEGACY_DEFAULT_SYSTEM_PROMPTS), (
+        "duplicate legacy revisions mean one of the derivations collapsed onto another"
+    )
+
+
+def test_the_web_ladder_tells_the_agent_to_try_the_cheap_tools_first():
+    """Eric's ask, and the reason the ladder step was rewritten: an agent given a plain reading task
+    was driving a browser instead of searching, which is far slower. The old wording filed the web
+    tools under 'No tool fits', which reads as a last resort."""
+    assert "WebSearch / WebFetch first" in DEFAULT_SYSTEM_PROMPT
+    assert "No tool fits." not in DEFAULT_SYSTEM_PROMPT, "the last-resort framing is back"
+    ladder = DEFAULT_SYSTEM_PROMPT[DEFAULT_SYSTEM_PROMPT.index("5. **Reading the web.**"):]
+    web_at = ladder.index("WebSearch")
+    browser_at = ladder.index("BrowserAgent")
+    assert web_at < browser_at, "the browser must not be named before the cheap tools"
+    assert "Escalate to BrowserAgent only" in DEFAULT_SYSTEM_PROMPT, "the fallback must stay conditional"
+
+
+def test_a_user_customized_prompt_is_never_mistaken_for_a_default():
+    """The migration is a verbatim match, so an edited prompt must never collide with a shipped one."""
+    customized = DEFAULT_SYSTEM_PROMPT + "\nAlways answer in French.\n"
+    assert customized not in P_LEGACY_DEFAULT_SYSTEM_PROMPTS