diff --git a/allways/__init__.py b/allways/__init__.py
index 9522109..8d9040a 100644
--- a/allways/__init__.py
+++ b/allways/__init__.py
@@ -1,3 +1,3 @@
-__version__ = '1.0.6'
+__version__ = '1.0.7'
 version_split = __version__.split('.')
 __spec_version__ = (1000 * int(version_split[0])) + (10 * int(version_split[1])) + (1 * int(version_split[2]))
diff --git a/allways/chains.py b/allways/chains.py
index 56dc645..d30d816 100644
--- a/allways/chains.py
+++ b/allways/chains.py
@@ -21,6 +21,9 @@ class ChainDefinition:
     env_prefix: str  # .env variable prefix (e.g. 'BTC' -> BTC_RPC_URL)
     seconds_per_block: int = 12  # Average block time on this chain
     min_confirmations: int = 1  # Minimum confirmations before accepting a transaction
+    # Smallest amount that can actually exist/move on-chain, in native units
+    # (BTC dust floor, TAO existential deposit). 1 = no floor.
+    min_onchain_amount: int = 1
 
 
 # ─── Supported Chains ────────────────────────────────────
@@ -32,6 +35,8 @@ class ChainDefinition:
     env_prefix='BTC',
     seconds_per_block=600,
     min_confirmations=2,
+    # 1000 sat, not the bare 546 P2PKH dust line: margin vs higher dustrelayfee / wallet quirks, and a tighter executable-rate ceiling.
+    min_onchain_amount=1000,
 )
 CHAIN_TAO = ChainDefinition(
     id='tao',
@@ -41,6 +46,8 @@ class ChainDefinition:
     env_prefix='TAO',
     seconds_per_block=12,
     min_confirmations=6,
+    # Existential deposit: accounts below this are reaped.
+    min_onchain_amount=500,
 )
 
 SUPPORTED_CHAINS = {
diff --git a/allways/utils/rate.py b/allways/utils/rate.py
index 38f3af6..42ea538 100644
--- a/allways/utils/rate.py
+++ b/allways/utils/rate.py
@@ -127,19 +127,20 @@ def is_executable_rate(
     min_swap_rao: int,
     max_swap_rao: int,
 ) -> bool:
-    """True iff the rate is integer-routable in its declared direction.
+    """True iff the rate is fundably routable in its declared direction.
 
-    Crown-eligibility gate against sentinel rates that no user can route:
+    Crown-eligibility gate against rates that no user can route. Routable means
+    a source >= the source chain's ``min_onchain_amount`` (dust / existential
+    deposit) maps a TAO leg into ``[min_swap_rao, max_swap_rao]`` — a rate whose
+    only in-bounds source is sub-dust (e.g. 1 sat -> 0.5 TAO at 5e7 TAO/BTC) is
+    unfundable, so unexecutable.
 
-    * BTC→TAO: high-side sentinels (``1e10``, ``1.797e308`` TAO/BTC) — the
-      smallest positive sat already maps above ``max_swap_rao``, so no
-      positive integer source produces an in-bounds TAO leg.
-    * TAO→BTC: low-side sentinels (``1e-8`` TAO/BTC) — the TAO leg IS the
-      source amount, so it trivially fits any bounds, but the destination
-      payout implied by the rate is absurd. Catch this by the symmetric
-      check on the inverse rate: if treating ``1/rate`` as a BTC→TAO rate
-      has no integer-routable source either, the original rate is at an
-      extreme of the executable spectrum and a sentinel by symmetry.
+    * BTC→TAO: high-side rates — even the smallest fundable sat maps above
+      ``max_swap_rao``, so no fundable source produces an in-bounds TAO leg.
+    * TAO→BTC: low-side rates — the TAO leg IS the source, so it trivially fits
+      any bounds, but the destination payout is absurd. Caught by the symmetric
+      check on ``1/rate``: if the inverse direction has no fundable source, the
+      original rate is at an extreme of the executable spectrum.
 
     A bound at ``0`` is the contract's "unset" sentinel and disables that
     side; both at 0 → permissive (no on-chain bounds yet).
@@ -151,15 +152,18 @@ def is_executable_rate(
 
     def _has_integer_routable_source(forward_rate: float, src_chain: str) -> bool:
         # For a "src → tao" direction at ``forward_rate`` (tao per src), is
-        # there a positive integer src amount whose TAO leg lands in bounds?
-        src_decimals = get_chain(src_chain).decimals
-        decimal_factor = 10 ** (get_chain('tao').decimals - src_decimals)
+        # there an src amount that is fundable on-chain (>= the chain's
+        # min_onchain_amount) whose TAO leg lands in bounds?
+        src = get_chain(src_chain)
+        decimal_factor = 10 ** (get_chain('tao').decimals - src.decimals)
         denom = forward_rate * decimal_factor
         if not math.isfinite(denom) or denom <= 0:
             # rate × decimal_factor overflowed (e.g. 1.797e308 × 10) → smallest
             # positive integer source already maps above any finite max bound.
             return False
-        min_source = max(1, math.ceil(max(1, min_swap_rao) / denom))
+        # Floor at the source chain's dust/existential minimum: a rate whose only
+        # in-bounds source is below it (e.g. 1 sat) is unfundable, so unexecutable.
+        min_source = max(src.min_onchain_amount, math.ceil(max(1, min_swap_rao) / denom))
         if max_swap_rao <= 0:
             return True
         max_source = math.floor(max_swap_rao / denom)
diff --git a/pyproject.toml b/pyproject.toml
index 1991816..7bbe497 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "allways"
-version = "1.0.6"
+version = "1.0.7"
 description = "Allways - Universal Transaction Layer: Trustless cross-chain swaps on Bittensor Subnet 7"
 license = "MIT"
 requires-python = ">=3.10,<3.15"
diff --git a/tests/test_rate.py b/tests/test_rate.py
index 372e195..4682551 100644
--- a/tests/test_rate.py
+++ b/tests/test_rate.py
@@ -2,6 +2,7 @@
 
 from decimal import Decimal
 
+from allways.chains import get_chain
 from allways.constants import BTC_TO_SAT, RATE_PRECISION, TAO_TO_RAO
 from allways.utils.rate import apply_fee_deduction, calculate_to_amount, is_executable_rate, normalize_rate
 
@@ -326,30 +327,38 @@ def test_tao_to_btc_lowball_rate_rejected(self):
         max_swap on the TAO leg, so the original rate is sentinel-low."""
         assert is_executable_rate(1e-8, 'tao', 'btc', self.MIN, self.MAX) is False
 
-    def test_boundary_rate_executable_at_one_sat(self):
-        """At max_swap/10 = 50_000_000 rao per sat, the smallest integer sat
-        produces exactly max_swap — should be executable."""
-        rate = self.MAX / 10  # TAO leg at 1 sat == max_swap
-        assert is_executable_rate(rate, 'btc', 'tao', self.MIN, self.MAX) is True
+    DUST = get_chain('btc').min_onchain_amount  # smallest fundable BTC source
 
-    def test_just_past_boundary_rate_rejected(self):
-        """A rate that maps 1 sat just above max_swap → no executable sat."""
-        rate = (self.MAX / 10) * 1.0001
+    def test_sub_dust_boundary_rate_rejected(self):
+        """At max_swap/10, the only in-bounds source is 1 sat — below the BTC
+        dust floor, so unfundable. Rejected (the crown-squat rate)."""
+        rate = self.MAX / 10  # TAO leg at 1 sat == max_swap; 1 sat < dust
         assert is_executable_rate(rate, 'btc', 'tao', self.MIN, self.MAX) is False
 
-    def test_tao_to_btc_boundary_rate_executable_at_one_sat(self):
-        """Symmetric boundary: at inverse=max_swap/10 (i.e. r = 10/max_swap),
-        treating 1/r as btc→tao maps 1 sat to exactly max_swap on the TAO leg.
-        Just executable."""
-        rate = 10 / self.MAX  # 1/r * 10 == max_swap; 1 sat at inverse hits max
-        assert is_executable_rate(rate, 'tao', 'btc', self.MIN, self.MAX) is True
+    def test_dust_floor_boundary_rate_executable(self):
+        """At the rate where the dust floor maps exactly to max_swap, the
+        smallest fundable source is in-bounds — just executable."""
+        rate = self.MAX / (10 * self.DUST)  # DUST sat → max_swap on the TAO leg
+        assert is_executable_rate(rate, 'btc', 'tao', self.MIN, self.MAX) is True
 
-    def test_tao_to_btc_just_past_boundary_rate_rejected(self):
-        """One ULP below the boundary: the inverse rate's 1 sat overshoots
-        max_swap, so no integer source routes by symmetry."""
-        rate = (10 / self.MAX) * 0.9999
+    def test_just_past_dust_floor_boundary_rejected(self):
+        """Just above the boundary, even the dust floor overshoots max_swap →
+        no fundable source routes."""
+        rate = (self.MAX / (10 * self.DUST)) * 1.0001
+        assert is_executable_rate(rate, 'btc', 'tao', self.MIN, self.MAX) is False
+
+    def test_tao_to_btc_sub_dust_boundary_rate_rejected(self):
+        """Symmetric: r = 10/max_swap maps 1 sat (sub-dust) to max_swap on the
+        inverse leg — rejected (the swap-1670 tao→btc crown-squat rate)."""
+        rate = 10 / self.MAX
         assert is_executable_rate(rate, 'tao', 'btc', self.MIN, self.MAX) is False
 
+    def test_tao_to_btc_dust_floor_boundary_executable(self):
+        """Symmetric boundary at the dust floor: the dust-clearing inverse
+        source maps in-bounds — just executable."""
+        rate = (10 * self.DUST) / self.MAX
+        assert is_executable_rate(rate, 'tao', 'btc', self.MIN, self.MAX) is True
+
     def test_tao_to_btc_sentinel_unset_bounds_still_permissive(self):
         """Unset bounds disable the gate in both directions — keeps the
         legacy "no on-chain bounds yet" path permissive."""
diff --git a/uv.lock b/uv.lock
index 7a3cfd0..f6427db 100644
--- a/uv.lock
+++ b/uv.lock
@@ -164,7 +164,7 @@ wheels = [
 
 [[package]]
 name = "allways"
-version = "1.0.6"
+version = "1.0.7"
 source = { editable = "." }
 dependencies = [
     { name = "base58" },