Level: Assassin 1, Sorcerer 0, Wizard 0
Components: S
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One portal
Saving Throw: Will negates (object)
Spell Resistance: Yes (object)
The door squeaks slightly as you force it. You pause and wave your finger in a pattern along the opening and it silences.
This simple cantrip negates the sound of opening and closing a single portal (door, window, gate, drawer, chest lid, or the like). Even the squeakiest door opens without a sound when under the effect of this spell. Silent portal covers only the normal means of opening and closing the targeted portal. Breaking a window or kicking in a door still makes noise, but opening a door that is loosely hanging by its hinges does not (since this is the normal way a door would be opened). Portals composed of magical energy are not affected by this spell.
In the case of magic or even intelligent portals, spell resistance and a Will save (DC 10 + caster’s ability modifier + other modifiers as appropriate) apply.
Source: Spell Compendium, page 190.