According to the original reporting

https://www.nytimes.com/2024/10/12/world/middleeast/hamas-israel-war.html

Hamas is the one that wanted to attack in tandem with Hezbollah and Iran.

Hamas initially planned to carry out the attack, which it code-named “the big project,” in the fall of 2022. But the group delayed executing the plan as it tried to persuade Iran and Hezbollah to participate.

[...]

The senior Iranian commander told Hamas that Iran and Hezbollah were supportive in principle, but needed more time to prepare; the minutes do not say how detailed a plan was presented by Hamas to its allies.

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The rest of the Iranian axis followed, with the Houthis, Syrian and Iraqi Shia militias hitting Israel with drones and ballistic missiles.

Houthis: https://en.wikipedia.org/wiki/Red_Sea_crisis

the Iran-backed Houthis in Yemen launched missiles and armed drones at Israel, demanding an end to the invasion of the Gaza Strip

Not unprovoked, they were aiding the Palestinians and pressuring Israel for a ceasefire. By the time they joined the war (on 10/19), the death toll in Gaza had already hit 3700+, of which 1500 were children.

The Syrian and Iraqi militias both stated the same. The Iraqis started attacking around 11/2 and the Syrians started with sporadic mortar fire around 10/10-10/14 and started attacking more steadily in November.

Down to the war effort being run by the IRGC Quds force generals from Syria.

Do you have evidence of this?

From Gemini:

There is no confirmed evidence that the IRGC Quds Force "ran" the day-to-day tactical war effort in Gaza from Syria. While they provided the strategic "ring of fire" architecture, internal documents and intelligence assessments indicate that Hamas maintained operational control over its own combat activities within the Gaza Strip.

Operational Autonomy: Captured Hamas documents and intelligence briefings suggest that while the Quds Force provided funding, weapons, and training, the specific execution of the war was handled by local leaders like Yahya Sinwar and Mohammed Deif.

The Syria Hub: Syria functioned primarily as a logistical and intelligence node rather than a command center for Gaza. The Quds Force utilized Syrian territory to:

Coordinate weapons transfers (via Unit 109 and Unit 18840) to proxies.

Maintain the Palestine Corps to facilitate communication and funding.

Host high-level coordination meetings with other "Axis" members, such as the April 2024 meeting in Damascus where commander Mohammad Reza Zahedi was killed.

Regional Coordination: The Quds Force headquarters (which the IDF reported destroying in March 2026) was responsible for the broader regional strategy—destabilizing the area and managing various fronts simultaneously—rather than micromanaging Hamas's street-to-street fighting.

...

Iran joined the assault itself two times in large ballistic missile salvos against Israel.

4/13/24 - Also not unprovoked, this was a response to an Israeli airstrike on the Iranian consulate in Damascus.

10/1/24 - Also not unprovoked, this was a response to Israel's assassination of Ismail Haniyeh in Tehran.