Unity Ml Agents Dynamic Object Observation With Null Safety

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 04e912cff54b · 14 Oct 2026Report an issue or request a re-scan

• PublisherECNU-ICALK GitHub organizationOwner of the repository this skill is read from
• Source folderECNU-ICALK/AutoSkill/SkillBank/ConvSkill/english_gpt4_8_GLM4.7/unity-ml-agents-dynamic-object-observation-with-null-safetyThe exact folder we audited
• LicenceNot declaredAs the repository states it
• Commit pinned for this verdict04e912cff54bA new audit runs when the source changes
• Repository statusNot archivedLast push 157 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Implement the CollectObservations method for a Unity ML-Agent to track the agent's position and a list of dynamic objects (like food) relative to the agent, ensuring null checks prevent errors when objects are destroyed.

---
id: "ad853a65-aba7-4cdd-9305-e4093a5b90fa"
name: "Unity ML-Agents Dynamic Object Observation with Null Safety"
description: "Implement the CollectObservations method for a Unity ML-Agent to track the agent's position and a list of dynamic objects (like food) relative to the agent, ensuring null checks prevent errors when objects are destroyed."
version: "0.1.0"
tags:
  - "Unity"
  - "ML-Agents"
  - "Observations"
  - "C#"
  - "2D"
triggers:
  - "collect the position of the player and food as an observation"
  - "Unity ML-Agents observation for food list"
  - "handle eaten food in CollectObservations"
  - "add food positions relative to player"
---

# Unity ML-Agents Dynamic Object Observation with Null Safety

Implement the CollectObservations method for a Unity ML-Agent to track the agent's position and a list of dynamic objects (like food) relative to the agent, ensuring null checks prevent errors when objects are destroyed.

## Prompt

# Role & Objective
You are a Unity ML-Agents developer specializing in 2D environments. Your task is to implement the `CollectObservations` method for an Agent that needs to track its own position and the positions of a list of dynamic objects (e.g., food items) managed by a parent area (e.g., TrainingArea).

# Operational Rules & Constraints
1. **Agent Position**: Add the agent's position (usually `transform.localPosition`) to the sensor.
2. **Target List Iteration**: Retrieve the list of target GameObjects from the parent area (e.g., `trainingArea.GetFoodInstances()`).
3. **Relative Position Calculation**: For each target in the list, calculate the position relative to the agent (`target.transform.localPosition - transform.localPosition`).
4. **Null Safety**: Before accessing the target's transform, check if the GameObject is null. This is critical because targets may be eaten/destroyed during the episode.
5. **Default Value for Nulls**: If a target is null, add a default observation (e.g., `Vector3.zero`) to the sensor to maintain consistent observation space dimensions and prevent runtime errors.
6. **Sensor Usage**: Use the provided `VectorSensor` to add observations.

# Anti-Patterns
- Do not access `transform` on a null GameObject.
- Do not skip observations for null items unless the observation space size is dynamic; usually, a placeholder value is preferred to keep the observation vector size constant.
- Do not use world positions if the agent relies on local coordinates for training stability, unless specified otherwise.

## Triggers

- collect the position of the player and food as an observation
- Unity ML-Agents observation for food list
- handle eaten food in CollectObservations
- add food positions relative to player

Excerpt, first 2,718 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/ECNU-ICALK/AutoSkill
git -C AutoSkill checkout 04e912cff54b

Works in

1. 2026-10-14
   ✓SAFE B 89 / 100

   first audit · source 04e912cff54b

Questions about Unity Ml Agents Dynamic Object Observation With Null Safety

• github.com/ECNU-ICALK/AutoSkill/tree/main/SkillBank/ConvSkill/en — the audited source at commit 04e912cff54b and every finding aboveObserved · 14 Oct 2026

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