drivers-and-app-handlers SKILL.md skillB
drivers-and-app-handlers from tmhsdigital/blender-developer-tools is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add tmhsdigital/blender-developer-tools/drivers-and-app-handlers@git:20261007.4636c25Pins git:20261007.4636c25 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- B, 16 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- tmhsdigital/blender-developer-tools
- Path
skills/drivers-and-app-handlers/SKILL.md- Versions recorded
- 11
- Latest version
- git:20261007.4636c25, committed Oct 7, 2026
- First version recorded
- Jun 13, 2026
- Size
- 19,206 bytes
- Repository stars
- 17
- License
- a license file GitHub does not identify
Drive properties from expressions with the Driver API (driver_add, driver_namespace for custom Python functions) and react to events with bpy.app.handlers (load_post, save_pre, frame_change_post, depsgraph_update_post, exit_pre in 5.1+). Use when the user wants one property to follow another, runs code on load, save, frame change or exit, or has a driver failing with NameError or the Python security block, including drivers that die after reopening a file.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Drivers and Application Handlers ## Trigger Use this skill when the user: - Wants property A to follow property B with some math (driver) - Asks about `driver_add`, `FCurve.driver`, `driver.expression`, `driver_namespace` - Wants to run code on file save, file load, frame change, depsgraph update, or process exit - Mentions `bpy.app.handlers`, `save_pre`, `load_post`, `depsgraph_update_post`, `exit_pre` - Has a driver expression that fails security checks because it tries to call a Python function This skill bundles two related "reactive" patterns. They show up together often (a driver that calls a function registered on a handler), so they share one skill. ## Part 1: Drivers ### What a driver is A driver replaces a static animation curve with a real-time-evaluated expression. It is attached to one property (the **target**) and reads zero or more other properties (the **variables**), then evaluates a string expression to compute the target's value on each frame. Concretely: an `FCurve` whose `.driver` field is set is a driver. The animation system evaluates `driver.expression` instead of sampling the curve. ### The Driver API ```python import bpy …
Read the whole file at its exact version.
How to install
mdr add tmhsdigital/blender-developer-tools/drivers-and-app-handlers@sha256:bb24a95491975481The line at the top of this page pins the label git:20261007.4636c25, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_mommqg4w3tm2qk2g)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 11 versions of this file, between Jun 13, 2026 and Oct 7, 2026, about one every 12 days. Its first recorded version is graded A and its latest B.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261007.4636c25 latest | 2026-10-07 | 4636c25 | 19,206 B | B | view · diff |
| git:20261005.f80411b | 2026-10-05 | f80411b | 16,581 B | B | view · diff |
| git:20261005.5e0299c | 2026-10-05 | 5e0299c | 15,679 B | A | view · diff |
| git:20261005.b612f3a | 2026-10-05 | b612f3a | 15,478 B | A | view · diff |
| git:20261005.e1d8310 | 2026-10-05 | e1d8310 | 15,241 B | A | view · diff |
| git:20261005.ae57f0d | 2026-10-05 | ae57f0d | 13,664 B | A | view · diff |
| git:20260910.bb5a2df | 2026-09-10 | bb5a2df | 13,433 B | A | view · diff |
| git:20260619.f21a7d4 | 2026-06-19 | f21a7d4 | 13,087 B | A | view · diff |
| git:20260618.5f6cbdf | 2026-06-18 | 5f6cbdf | 12,774 B | A | view · diff |
| git:20260618.c39032d | 2026-06-18 | c39032d | 12,518 B | A | view · diff |
| git:20260613.e6324e5 | 2026-06-13 | e6324e5 | 11,375 B | A | view |
Audit of the latest version
- fail: No script tag (matched: <script)
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (19206 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
Starting a new one? Use a template for SKILL.md on mdpantry, which passes every one of these checks and says what to change in it.
Source
tmhsdigital/blender-developer-tools · 17 stars · license a license file GitHub does not identify · pushed 2026-10-18 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_mommqg4w3tm2qk2g GET https://markdownregistry.com/api/v1/resolve?ref=tmhsdigital/blender-developer-tools/drivers-and-app-handlers GET https://markdownregistry.com/api/v1/blob/bb24a954919754810ff09cc2bf628bd0de6b1aaed32eee1c6655ead03205476d
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.