How does two-weapon fighting work when using an off-hand triple dagger?

Question

The triple dagger (Arms and Equipment Guide 6, 10) (10 gp; 1 lb.) is—with some minor adjustments due to the Dungeons and Dragons 3.5 revision—a light exotic melee weapon that deals 1d4 points of damage and has a critical of 19–20/×2. In addition, it has this untouched description:

This weapon is used in the off hand as a means to disarm an opponent—you hold it as you would a shield, not another weapon, and so do not take penalties for fighting with two weapons. When using a triple dagger, you get a +3 circumstance bonus on your opposed attack roll when attempting to disarm an opponent (including the roll to keep from being disarmed if you fail to disarm your opponent). The triple dagger could also be used as a normal dagger, if desired, but if used in the off hand, all normal penalties for fighting with two weapons apply.

Emphasis mine. Is that boldfaced text misunderstanding how two-weapon fighting works? (That is, a creature is two-weapon fighting when it attacks with two separate weapons not when it merely wields them.) Or is that boldfaced text saying that, when the triple dagger occupies the same position a shield would, the creature can two-weapon fight using the triple dagger as its off-hand weapon and make all its two-weapon fighting attacks without suffering any two-weapon fighting penalties? Or is there another way of reading this weapon's description?

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Note: While from a Dungeons and Dragons, Third Edition source, the triple dagger is, so far as I'm aware, never updated to Dungeons and Dragons 3.5. Hence the version presented here is post- 3.5 revision game-legal. Tags reflect both this weapon's provenance and the potential of the asker to use the weapon in a 3.5 campaign. While I'd prefer a rules-as-written answer, because the 3.5 revision explicitly permits the DM to make minor adjustments to unrevised 3e material, other answers that hew closely to the rules are fine.

Answer 1

Given that there is this passage:

The triple dagger could also be used as a normal dagger, if desired, but if used in the off hand, all normal penalties for fighting with two weapons apply.

I would think that the real emphasis is that the triple dagger has two distinct usage modes, one carrying a penalty to attack rolls, and the other not.

The first mode, codified by:

This weapon is used in the off hand as a means to disarm an opponent—you hold it as you would a shield, not another weapon, and so do not take penalties for fighting with two weapons. When using a triple dagger, you get a +3 circumstance bonus on your opposed attack roll when attempting to disarm an opponent (including the roll to keep from being disarmed if you fail to disarm your opponent).

is that you need to hold the triple dagger in your off-hand, and are considered using it, albeit with no penalty since you are not attacking with it, to gain the +3 circumstance bonus to disarm.

The second mode, codified by the last sentence, is that the weapon can be use as a regular dagger, to attack.

And, critically, the weapon cannot be used in both modes simultaneously: it either behaves "as a shield" and grant a bonus to Disarm with no penalty on attack rolls OR behaves "as a dagger" and be subject to all regular rules.

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The triple dagger is an Exotic Weapon, and as such requires a feat - Exotic Weapon Proficiency (Triple Dagger) - to use it without penalties.

According to the Exotic Weapon Proficiency:

A character who uses a weapon with which he or she is not proficient takes a -4 penalty on attack rolls.

Of note, this is not "A character who attacks", and therefore it seems logical that the penalty applies both for attacking and for obtaining the +3 Circumstance bonus to Disarm. It would also seem logical that the penalty does not apply for merely holding the Triple Dagger without making use of it.

There is also the question of the action cost of switching modes between simple blade mode and triple blade mode. For a proficient user, it seems to be a Free Action; it is unclear how much time it would cost a non-proficient user, however seeing as they would already suffer a -4 penalty to attack rolls, using either a Free or Swift action seems enough.

These details should be agreed upon with the DM ahead of time. And the discussion would be a good time to bring up the fact that since a spellcaster does not need a feat to use a new spell, maybe the poor fighter should not need a feat to use a new weapon either.